SpotShadow.cpp revision b79a3e301a8d89b9e1b1f6f3d7fd6aa56610a6f0
17b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/* 27b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Copyright (C) 2014 The Android Open Source Project 37b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 47b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Licensed under the Apache License, Version 2.0 (the "License"); 57b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * you may not use this file except in compliance with the License. 67b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * You may obtain a copy of the License at 77b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 87b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * http://www.apache.org/licenses/LICENSE-2.0 97b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Unless required by applicable law or agreed to in writing, software 117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * distributed under the License is distributed on an "AS IS" BASIS, 127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * See the License for the specific language governing permissions and 147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * limitations under the License. 157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#define LOG_TAG "OpenGLRenderer" 187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#define SHADOW_SHRINK_SCALE 0.1f 207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#include <math.h> 22f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui#include <stdlib.h> 237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#include <utils/Log.h> 247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2563d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui#include "ShadowTessellator.h" 267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#include "SpotShadow.h" 277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#include "Vertex.h" 287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuinamespace android { 307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuinamespace uirenderer { 317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 32726118b35240957710d4d85fb5747e2ba8b934f7Chris Craikstatic const double EPSILON = 1e-7; 33726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 34726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik/** 35726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * Calculate the angle between and x and a y coordinate. 36726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * The atan2 range from -PI to PI. 37726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik */ 38b79a3e301a8d89b9e1b1f6f3d7fd6aa56610a6f0Chris Craikstatic float angle(const Vector2& point, const Vector2& center) { 39726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik return atan2(point.y - center.y, point.x - center.x); 40726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik} 41726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 43726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * Calculate the intersection of a ray with the line segment defined by two points. 447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 45726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * Returns a negative value in error conditions. 46726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 47726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * @param rayOrigin The start of the ray 48726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * @param dx The x vector of the ray 49726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * @param dy The y vector of the ray 50726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * @param p1 The first point defining the line segment 51726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * @param p2 The second point defining the line segment 52726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * @return The distance along the ray if it intersects with the line segment, negative if otherwise 537b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 54b79a3e301a8d89b9e1b1f6f3d7fd6aa56610a6f0Chris Craikstatic float rayIntersectPoints(const Vector2& rayOrigin, float dx, float dy, 55726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik const Vector2& p1, const Vector2& p2) { 56726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik // The math below is derived from solving this formula, basically the 57726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik // intersection point should stay on both the ray and the edge of (p1, p2). 58726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik // solve([p1x+t*(p2x-p1x)=dx*t2+px,p1y+t*(p2y-p1y)=dy*t2+py],[t,t2]); 59726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 60726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik double divisor = (dx * (p1.y - p2.y) + dy * p2.x - dy * p1.x); 61726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik if (divisor == 0) return -1.0f; // error, invalid divisor 62726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 63726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik#if DEBUG_SHADOW 64726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik double interpVal = (dx * (p1.y - rayOrigin.y) + dy * rayOrigin.x - dy * p1.x) / divisor; 65726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik if (interpVal < 0 || interpVal > 1) return -1.0f; // error, doesn't intersect between points 66726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik#endif 67726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 68726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik double distance = (p1.x * (rayOrigin.y - p2.y) + p2.x * (p1.y - rayOrigin.y) + 69726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik rayOrigin.x * (p2.y - p1.y)) / divisor; 70726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 71726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik return distance; // may be negative in error cases 727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Sort points by their X coordinates 767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param points the points as a Vector2 array. 787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param pointsLength the number of vertices of the polygon. 797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::xsort(Vector2* points, int pointsLength) { 817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui quicksortX(points, 0, pointsLength - 1); 827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * compute the convex hull of a collection of Points 867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param points the points as a Vector2 array. 887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param pointsLength the number of vertices of the polygon. 897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param retPoly pre allocated array of floats to put the vertices 907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return the number of points in the polygon 0 if no intersection 917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuiint SpotShadow::hull(Vector2* points, int pointsLength, Vector2* retPoly) { 937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui xsort(points, pointsLength); 947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int n = pointsLength; 957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 lUpper[n]; 967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpper[0] = points[0]; 977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpper[1] = points[1]; 987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int lUpperSize = 2; 1007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 2; i < n; i++) { 1027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpper[lUpperSize] = points[i]; 1037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpperSize++; 1047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 105f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui while (lUpperSize > 2 && !ccw( 106f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui lUpper[lUpperSize - 3].x, lUpper[lUpperSize - 3].y, 107f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui lUpper[lUpperSize - 2].x, lUpper[lUpperSize - 2].y, 108f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui lUpper[lUpperSize - 1].x, lUpper[lUpperSize - 1].y)) { 1097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Remove the middle point of the three last 1107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpper[lUpperSize - 2].x = lUpper[lUpperSize - 1].x; 1117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpper[lUpperSize - 2].y = lUpper[lUpperSize - 1].y; 1127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpperSize--; 1137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 lLower[n]; 1177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lLower[0] = points[n - 1]; 1187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lLower[1] = points[n - 2]; 1197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int lLowerSize = 2; 1217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = n - 3; i >= 0; i--) { 1237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lLower[lLowerSize] = points[i]; 1247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lLowerSize++; 1257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 126f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui while (lLowerSize > 2 && !ccw( 127f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui lLower[lLowerSize - 3].x, lLower[lLowerSize - 3].y, 128f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui lLower[lLowerSize - 2].x, lLower[lLowerSize - 2].y, 129f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui lLower[lLowerSize - 1].x, lLower[lLowerSize - 1].y)) { 1307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Remove the middle point of the three last 1317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lLower[lLowerSize - 2] = lLower[lLowerSize - 1]; 1327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lLowerSize--; 1337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 136726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik // output points in CW ordering 137726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik const int total = lUpperSize + lLowerSize - 2; 138726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik int outIndex = total - 1; 1397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < lUpperSize; i++) { 140726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik retPoly[outIndex] = lUpper[i]; 141726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik outIndex--; 1427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 1; i < lLowerSize - 1; i++) { 145726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik retPoly[outIndex] = lLower[i]; 146726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik outIndex--; 1477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // TODO: Add test harness which verify that all the points are inside the hull. 149726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik return total; 1507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 1517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 153f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui * Test whether the 3 points form a counter clockwise turn. 1547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 1557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return true if a right hand turn 1567b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 157f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghuibool SpotShadow::ccw(double ax, double ay, double bx, double by, 1587b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double cx, double cy) { 1597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return (bx - ax) * (cy - ay) - (by - ay) * (cx - ax) > EPSILON; 1607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 1617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 1637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Calculates the intersection of poly1 with poly2 and put in poly2. 1647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 1657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 1667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly1 The 1st polygon, as a Vector2 array. 1677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly1Length The number of vertices of 1st polygon. 1687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly2 The 2nd and output polygon, as a Vector2 array. 1697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly2Length The number of vertices of 2nd polygon. 1707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return number of vertices in output polygon as poly2. 1717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 1727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuiint SpotShadow::intersection(Vector2* poly1, int poly1Length, 1737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2* poly2, int poly2Length) { 1747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui makeClockwise(poly1, poly1Length); 1757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui makeClockwise(poly2, poly2Length); 176f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 1777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 poly[poly1Length * poly2Length + 2]; 1787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int count = 0; 1797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int pcount = 0; 1807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // If one vertex from one polygon sits inside another polygon, add it and 1827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // count them. 1837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < poly1Length; i++) { 1847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (testPointInsidePolygon(poly1[i], poly2, poly2Length)) { 1857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly[count] = poly1[i]; 1867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui count++; 1877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui pcount++; 1887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int insidePoly2 = pcount; 1937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < poly2Length; i++) { 1947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (testPointInsidePolygon(poly2[i], poly1, poly1Length)) { 1957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly[count] = poly2[i]; 1967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui count++; 1977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int insidePoly1 = count - insidePoly2; 2017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // If all vertices from poly1 are inside poly2, then just return poly1. 2027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (insidePoly2 == poly1Length) { 2037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui memcpy(poly2, poly1, poly1Length * sizeof(Vector2)); 2047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return poly1Length; 2057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // If all vertices from poly2 are inside poly1, then just return poly2. 2087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (insidePoly1 == poly2Length) { 2097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return poly2Length; 2107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Since neither polygon fully contain the other one, we need to add all the 2137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // intersection points. 2147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 intersection; 2157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < poly2Length; i++) { 2167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int j = 0; j < poly1Length; j++) { 2177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int poly2LineStart = i; 2187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int poly2LineEnd = ((i + 1) % poly2Length); 2197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int poly1LineStart = j; 2207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int poly1LineEnd = ((j + 1) % poly1Length); 2217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui bool found = lineIntersection( 2227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly2[poly2LineStart].x, poly2[poly2LineStart].y, 2237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly2[poly2LineEnd].x, poly2[poly2LineEnd].y, 2247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly1[poly1LineStart].x, poly1[poly1LineStart].y, 2257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly1[poly1LineEnd].x, poly1[poly1LineEnd].y, 2267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui intersection); 2277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (found) { 2287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly[count].x = intersection.x; 2297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly[count].y = intersection.y; 2307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui count++; 2317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } else { 2327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 delta = poly2[i] - poly1[j]; 233f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui if (delta.lengthSquared() < EPSILON) { 2347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly[count] = poly2[i]; 2357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui count++; 2367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (count == 0) { 2427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return 0; 2437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Sort the result polygon around the center. 2467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 center(0.0f, 0.0f); 2477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < count; i++) { 2487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui center += poly[i]; 2497b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui center /= count; 2517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui sort(poly, count, center); 2527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 253f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui#if DEBUG_SHADOW 254f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui // Since poly2 is overwritten as the result, we need to save a copy to do 255f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui // our verification. 256f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui Vector2 oldPoly2[poly2Length]; 257f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui int oldPoly2Length = poly2Length; 258f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui memcpy(oldPoly2, poly2, sizeof(Vector2) * poly2Length); 259f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui#endif 2607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 261f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui // Filter the result out from poly and put it into poly2. 2627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly2[0] = poly[0]; 263f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui int lastOutputIndex = 0; 2647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 1; i < count; i++) { 265f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui Vector2 delta = poly[i] - poly2[lastOutputIndex]; 266f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui if (delta.lengthSquared() >= EPSILON) { 267f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui poly2[++lastOutputIndex] = poly[i]; 268f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } else { 269f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui // If the vertices are too close, pick the inner one, because the 270f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui // inner one is more likely to be an intersection point. 271f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui Vector2 delta1 = poly[i] - center; 272f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui Vector2 delta2 = poly2[lastOutputIndex] - center; 273f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui if (delta1.lengthSquared() < delta2.lengthSquared()) { 274f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui poly2[lastOutputIndex] = poly[i]; 275f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 2767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 278f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui int resultLength = lastOutputIndex + 1; 279f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 280f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui#if DEBUG_SHADOW 281f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui testConvex(poly2, resultLength, "intersection"); 282f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui testConvex(poly1, poly1Length, "input poly1"); 283f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui testConvex(oldPoly2, oldPoly2Length, "input poly2"); 284f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 285f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui testIntersection(poly1, poly1Length, oldPoly2, oldPoly2Length, poly2, resultLength); 286f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui#endif 2877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return resultLength; 2897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 2907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 2927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Sort points about a center point 2937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 2947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly The in and out polyogon as a Vector2 array. 2957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param polyLength The number of vertices of the polygon. 2967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param center the center ctr[0] = x , ctr[1] = y to sort around. 2977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 2987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::sort(Vector2* poly, int polyLength, const Vector2& center) { 2997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui quicksortCirc(poly, 0, polyLength - 1, center); 3007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 3017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 3037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Swap points pointed to by i and j 3047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 3057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::swap(Vector2* points, int i, int j) { 3067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 temp = points[i]; 3077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui points[i] = points[j]; 3087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui points[j] = temp; 3097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 3107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 3127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * quick sort implementation about the center. 3137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 3147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::quicksortCirc(Vector2* points, int low, int high, 3157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui const Vector2& center) { 3167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int i = low, j = high; 3177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int p = low + (high - low) / 2; 3187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float pivot = angle(points[p], center); 3197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui while (i <= j) { 320726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik while (angle(points[i], center) > pivot) { 3217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui i++; 3227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 323726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik while (angle(points[j], center) < pivot) { 3247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui j--; 3257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (i <= j) { 3287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui swap(points, i, j); 3297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui i++; 3307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui j--; 3317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (low < j) quicksortCirc(points, low, j, center); 3347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (i < high) quicksortCirc(points, i, high, center); 3357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 3367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 3387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Sort points by x axis 3397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 3407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param points points to sort 3417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param low start index 3427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param high end index 3437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 3447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::quicksortX(Vector2* points, int low, int high) { 3457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int i = low, j = high; 3467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int p = low + (high - low) / 2; 3477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float pivot = points[p].x; 3487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui while (i <= j) { 3497b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui while (points[i].x < pivot) { 3507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui i++; 3517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui while (points[j].x > pivot) { 3537b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui j--; 3547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3567b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (i <= j) { 3577b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui swap(points, i, j); 3587b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui i++; 3597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui j--; 3607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (low < j) quicksortX(points, low, j); 3637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (i < high) quicksortX(points, i, high); 3647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 3657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 3677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Test whether a point is inside the polygon. 3687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 3697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param testPoint the point to test 3707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly the polygon 3717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return true if the testPoint is inside the poly. 3727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 3737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuibool SpotShadow::testPointInsidePolygon(const Vector2 testPoint, 3747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui const Vector2* poly, int len) { 3757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui bool c = false; 3767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double testx = testPoint.x; 3777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double testy = testPoint.y; 3787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0, j = len - 1; i < len; j = i++) { 3797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double startX = poly[j].x; 3807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double startY = poly[j].y; 3817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double endX = poly[i].x; 3827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double endY = poly[i].y; 3837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (((endY > testy) != (startY > testy)) && 3857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui (testx < (startX - endX) * (testy - endY) 3867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui / (startY - endY) + endX)) { 3877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui c = !c; 3887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return c; 3917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 3927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 3947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Make the polygon turn clockwise. 3957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 3967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param polygon the polygon as a Vector2 array. 3977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param len the number of points of the polygon 3987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 3997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::makeClockwise(Vector2* polygon, int len) { 4007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (polygon == 0 || len == 0) { 4017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return; 4027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 4037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (!isClockwise(polygon, len)) { 4047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui reverse(polygon, len); 4057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 4067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 4077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 4097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Test whether the polygon is order in clockwise. 4107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 4117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param polygon the polygon as a Vector2 array 4127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param len the number of points of the polygon 4137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 4147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuibool SpotShadow::isClockwise(Vector2* polygon, int len) { 4157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double sum = 0; 4167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double p1x = polygon[len - 1].x; 4177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double p1y = polygon[len - 1].y; 4187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < len; i++) { 4197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double p2x = polygon[i].x; 4217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double p2y = polygon[i].y; 4227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui sum += p1x * p2y - p2x * p1y; 4237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui p1x = p2x; 4247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui p1y = p2y; 4257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 4267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return sum < 0; 4277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 4287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 4307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Reverse the polygon 4317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 4327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param polygon the polygon as a Vector2 array 4337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param len the number of points of the polygon 4347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 4357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::reverse(Vector2* polygon, int len) { 4367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int n = len / 2; 4377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < n; i++) { 4387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 tmp = polygon[i]; 4397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int k = len - 1 - i; 4407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui polygon[i] = polygon[k]; 4417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui polygon[k] = tmp; 4427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 4437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 4447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 4467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Intersects two lines in parametric form. This function is called in a tight 4477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * loop, and we need double precision to get things right. 4487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 4497b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param x1 the x coordinate point 1 of line 1 4507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param y1 the y coordinate point 1 of line 1 4517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param x2 the x coordinate point 2 of line 1 4527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param y2 the y coordinate point 2 of line 1 4537b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param x3 the x coordinate point 1 of line 2 4547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param y3 the y coordinate point 1 of line 2 4557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param x4 the x coordinate point 2 of line 2 4567b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param y4 the y coordinate point 2 of line 2 4577b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param ret the x,y location of the intersection 4587b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return true if it found an intersection 4597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 4607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuiinline bool SpotShadow::lineIntersection(double x1, double y1, double x2, double y2, 4617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double x3, double y3, double x4, double y4, Vector2& ret) { 4627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double d = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4); 4637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (d == 0.0) return false; 4647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double dx = (x1 * y2 - y1 * x2); 4667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double dy = (x3 * y4 - y3 * x4); 4677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double x = (dx * (x3 - x4) - (x1 - x2) * dy) / d; 4687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double y = (dx * (y3 - y4) - (y1 - y2) * dy) / d; 4697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // The intersection should be in the middle of the point 1 and point 2, 4717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // likewise point 3 and point 4. 4727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (((x - x1) * (x - x2) > EPSILON) 4737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui || ((x - x3) * (x - x4) > EPSILON) 4747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui || ((y - y1) * (y - y2) > EPSILON) 4757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui || ((y - y3) * (y - y4) > EPSILON)) { 4767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Not interesected 4777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return false; 4787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 4797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ret.x = x; 4807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ret.y = y; 4817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return true; 4827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 4847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 4867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Compute a horizontal circular polygon about point (x , y , height) of radius 4877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * (size) 4887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 4897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param points number of the points of the output polygon. 4907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param lightCenter the center of the light. 4917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param size the light size. 4927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param ret result polygon. 4937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 4947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::computeLightPolygon(int points, const Vector3& lightCenter, 4957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float size, Vector3* ret) { 4967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // TODO: Caching all the sin / cos values and store them in a look up table. 4977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < points; i++) { 4987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double angle = 2 * i * M_PI / points; 499726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik ret[i].x = cosf(angle) * size + lightCenter.x; 500726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik ret[i].y = sinf(angle) * size + lightCenter.y; 5017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ret[i].z = lightCenter.z; 5027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 5047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 5067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* Generate the shadow from a spot light. 5077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* 5087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param poly x,y,z vertexes of a convex polygon that occludes the light source 5097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param polyLength number of vertexes of the occluding polygon 5107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param lightCenter the center of the light 5117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param lightSize the radius of the light source 5127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param lightVertexCount the vertex counter for the light polygon 5137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param shadowTriangleStrip return an (x,y,alpha) triangle strip representing the shadow. Return 5147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* empty strip if error. 5157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* 5167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui*/ 5177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::createSpotShadow(const Vector3* poly, int polyLength, 5187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui const Vector3& lightCenter, float lightSize, int lightVertexCount, 51963d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui VertexBuffer& retStrips) { 5207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector3 light[lightVertexCount * 3]; 5217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui computeLightPolygon(lightVertexCount, lightCenter, lightSize, light); 52263d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui computeSpotShadow(light, lightVertexCount, lightCenter, poly, polyLength, 52363d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui retStrips); 5247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 5257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 5277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Generate the shadow spot light of shape lightPoly and a object poly 5287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 5297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param lightPoly x,y,z vertex of a convex polygon that is the light source 5307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param lightPolyLength number of vertexes of the light source polygon 5317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly x,y,z vertexes of a convex polygon that occludes the light source 5327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param polyLength number of vertexes of the occluding polygon 5337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param shadowTriangleStrip return an (x,y,alpha) triangle strip representing the shadow. Return 5347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * empty strip if error. 5357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 5367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::computeSpotShadow(const Vector3* lightPoly, int lightPolyLength, 5377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui const Vector3& lightCenter, const Vector3* poly, int polyLength, 53863d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui VertexBuffer& shadowTriangleStrip) { 5397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Point clouds for all the shadowed vertices 5407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 shadowRegion[lightPolyLength * polyLength]; 5417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Shadow polygon from one point light. 5427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 outline[polyLength]; 5437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 umbraMem[polyLength * lightPolyLength]; 5447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2* umbra = umbraMem; 5457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int umbraLength = 0; 5477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Validate input, receiver is always at z = 0 plane. 5497b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui bool inputPolyPositionValid = true; 5507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < polyLength; i++) { 5517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (poly[i].z <= 0.00001) { 5527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui inputPolyPositionValid = false; 553b79a3e301a8d89b9e1b1f6f3d7fd6aa56610a6f0Chris Craik ALOGW("polygon below the surface"); 5547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui break; 5557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5567b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (poly[i].z >= lightPoly[0].z) { 5577b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui inputPolyPositionValid = false; 558b79a3e301a8d89b9e1b1f6f3d7fd6aa56610a6f0Chris Craik ALOGW("polygon above the light"); 5597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui break; 5607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // If the caster's position is invalid, don't draw anything. 5647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (!inputPolyPositionValid) { 5657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return; 5667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Calculate the umbra polygon based on intersections of all outlines 5697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int k = 0; 5707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int j = 0; j < lightPolyLength; j++) { 5717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int m = 0; 5727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < polyLength; i++) { 5737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float t = lightPoly[j].z - poly[i].z; 5747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (t == 0) { 5757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return; 5767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui t = lightPoly[j].z / t; 5787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float x = lightPoly[j].x - t * (lightPoly[j].x - poly[i].x); 5797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float y = lightPoly[j].y - t * (lightPoly[j].y - poly[i].y); 5807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 newPoint = Vector2(x, y); 5827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui shadowRegion[k] = newPoint; 5837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui outline[m] = newPoint; 5847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui k++; 5867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui m++; 5877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // For the first light polygon's vertex, use the outline as the umbra. 5907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Later on, use the intersection of the outline and existing umbra. 5917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (umbraLength == 0) { 5927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < polyLength; i++) { 5937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui umbra[i] = outline[i]; 5947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui umbraLength = polyLength; 5967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } else { 5977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int col = ((j * 255) / lightPolyLength); 5987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui umbraLength = intersection(outline, polyLength, umbra, umbraLength); 5997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (umbraLength == 0) { 6007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui break; 6017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Generate the penumbra area using the hull of all shadow regions. 6067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int shadowRegionLength = k; 6077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 penumbra[k]; 6087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int penumbraLength = hull(shadowRegion, shadowRegionLength, penumbra); 6097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6105176c974f1d9af833b7584e895fcba61e6e7427aztenghui Vector2 fakeUmbra[polyLength]; 6117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (umbraLength < 3) { 6125176c974f1d9af833b7584e895fcba61e6e7427aztenghui // If there is no real umbra, make a fake one. 6137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < polyLength; i++) { 6147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float t = lightCenter.z - poly[i].z; 6157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (t == 0) { 6167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return; 6177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui t = lightCenter.z / t; 6197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float x = lightCenter.x - t * (lightCenter.x - poly[i].x); 6207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float y = lightCenter.y - t * (lightCenter.y - poly[i].y); 6217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6225176c974f1d9af833b7584e895fcba61e6e7427aztenghui fakeUmbra[i].x = x; 6235176c974f1d9af833b7584e895fcba61e6e7427aztenghui fakeUmbra[i].y = y; 6247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Shrink the centroid's shadow by 10%. 6277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // TODO: Study the magic number of 10%. 62863d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui Vector2 shadowCentroid = 62963d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui ShadowTessellator::centroid2d(fakeUmbra, polyLength); 6307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < polyLength; i++) { 6315176c974f1d9af833b7584e895fcba61e6e7427aztenghui fakeUmbra[i] = shadowCentroid * (1.0f - SHADOW_SHRINK_SCALE) + 6325176c974f1d9af833b7584e895fcba61e6e7427aztenghui fakeUmbra[i] * SHADOW_SHRINK_SCALE; 6337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#if DEBUG_SHADOW 6357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ALOGD("No real umbra make a fake one, centroid2d = %f , %f", 6367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui shadowCentroid.x, shadowCentroid.y); 6377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#endif 6387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Set the fake umbra, whose size is the same as the original polygon. 6395176c974f1d9af833b7584e895fcba61e6e7427aztenghui umbra = fakeUmbra; 6407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui umbraLength = polyLength; 6417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui generateTriangleStrip(penumbra, penumbraLength, umbra, umbraLength, 64463d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui shadowTriangleStrip); 6457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 6467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 648726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * Converts a polygon specified with CW vertices into an array of distance-from-centroid values. 649726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * 650726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * Returns false in error conditions 651726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * 652726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * @param poly Array of vertices. Note that these *must* be CW. 653726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * @param polyLength The number of vertices in the polygon. 654726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * @param polyCentroid The centroid of the polygon, from which rays will be cast 655726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * @param rayDist The output array for the calculated distances, must be SHADOW_RAY_COUNT in size 656726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik */ 657726118b35240957710d4d85fb5747e2ba8b934f7Chris Craikbool convertPolyToRayDist(const Vector2* poly, int polyLength, const Vector2& polyCentroid, 658726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik float* rayDist) { 659726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik const int rays = SHADOW_RAY_COUNT; 660726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik const float step = M_PI * 2 / rays; 661726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 662726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik const Vector2* lastVertex = &(poly[polyLength - 1]); 663726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik float startAngle = angle(*lastVertex, polyCentroid); 664726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 665726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik // Start with the ray that's closest to and less than startAngle 666726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik int rayIndex = floor((startAngle - EPSILON) / step); 667726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik rayIndex = (rayIndex + rays) % rays; // ensure positive 668726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 669726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik for (int polyIndex = 0; polyIndex < polyLength; polyIndex++) { 670726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik /* 671726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * For a given pair of vertices on the polygon, poly[i-1] and poly[i], the rays that 672726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * intersect these will be those that are between the two angles from the centroid that the 673726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * vertices define. 674726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * 675726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * Because the polygon vertices are stored clockwise, the closest ray with an angle 676726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * *smaller* than that defined by angle(poly[i], centroid) will be the first ray that does 677726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik * not intersect with poly[i-1], poly[i]. 678726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik */ 679726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik float currentAngle = angle(poly[polyIndex], polyCentroid); 680726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 681726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik // find first ray that will not intersect the line segment poly[i-1] & poly[i] 682726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik int firstRayIndexOnNextSegment = floor((currentAngle - EPSILON) / step); 683726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik firstRayIndexOnNextSegment = (firstRayIndexOnNextSegment + rays) % rays; // ensure positive 684726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 685726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik // Iterate through all rays that intersect with poly[i-1], poly[i] line segment. 686726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik // This may be 0 rays. 687726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik while (rayIndex != firstRayIndexOnNextSegment) { 688726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik float distanceToIntersect = rayIntersectPoints(polyCentroid, 689726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik cos(rayIndex * step), 690726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik sin(rayIndex * step), 691726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik *lastVertex, poly[polyIndex]); 692726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik if (distanceToIntersect < 0) return false; // error case, abort 693726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 694726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik rayDist[rayIndex] = distanceToIntersect; 695726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 696726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik rayIndex = (rayIndex - 1 + rays) % rays; 697726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik } 698726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik lastVertex = &poly[polyIndex]; 699726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik } 700726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 701726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik return true; 702726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik} 703726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 704726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik/** 7057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Generate a triangle strip given two convex polygons 7067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 7077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param penumbra The outer polygon x,y vertexes 7087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param penumbraLength The number of vertexes in the outer polygon 7097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param umbra The inner outer polygon x,y vertexes 7107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param umbraLength The number of vertexes in the inner polygon 7117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param shadowTriangleStrip return an (x,y,alpha) triangle strip representing the shadow. Return 7127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * empty strip if error. 7137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui**/ 7147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::generateTriangleStrip(const Vector2* penumbra, int penumbraLength, 71563d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui const Vector2* umbra, int umbraLength, VertexBuffer& shadowTriangleStrip) { 71663d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui const int rays = SHADOW_RAY_COUNT; 7177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 718726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik const int size = 2 * rays; 719726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik const float step = M_PI * 2 / rays; 7207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Centroid of the umbra. 72163d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui Vector2 centroid = ShadowTessellator::centroid2d(umbra, umbraLength); 7227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#if DEBUG_SHADOW 7237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ALOGD("centroid2d = %f , %f", centroid.x, centroid.y); 7247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#endif 7257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Intersection to the penumbra. 7267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float penumbraDistPerRay[rays]; 7277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Intersection to the umbra. 7287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float umbraDistPerRay[rays]; 7297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 730726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik // convert CW polygons to ray distance encoding, aborting on conversion failure 731726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik if (!convertPolyToRayDist(umbra, umbraLength, centroid, umbraDistPerRay)) return; 732726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik if (!convertPolyToRayDist(penumbra, penumbraLength, centroid, penumbraDistPerRay)) return; 7337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 734726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik AlphaVertex* shadowVertices = shadowTriangleStrip.alloc<AlphaVertex>(getStripSize(rays)); 7357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 73663d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui // Calculate the vertices (x, y, alpha) in the shadow area. 737726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik for (int rayIndex = 0; rayIndex < rays; rayIndex++) { 738726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik float dx = cosf(step * rayIndex); 739726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik float dy = sinf(step * rayIndex); 740726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 741726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik // outer ring 742726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik float currentDist = penumbraDistPerRay[rayIndex]; 743726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik AlphaVertex::set(&shadowVertices[rayIndex], 744726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik dx * currentDist + centroid.x, dy * currentDist + centroid.y, 0.0f); 745726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik 746726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik // inner ring 747726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik float deltaDist = umbraDistPerRay[rayIndex] - penumbraDistPerRay[rayIndex]; 748726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik currentDist += deltaDist; 749726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik AlphaVertex::set(&shadowVertices[rays + rayIndex], 750726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik dx * currentDist + centroid.x, dy * currentDist + centroid.y, 1.0f); 7517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 75263d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui // The centroid is in the umbra area, so the opacity is considered as 1.0. 753726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik AlphaVertex::set(&shadowVertices[SHADOW_VERTEX_COUNT - 1], centroid.x, centroid.y, 1.0f); 7547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#if DEBUG_SHADOW 7557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < currentIndex; i++) { 75663d41abb40b3ce40d8b9bccb1cf186e8158a3687ztenghui ALOGD("spot shadow value: i %d, (x:%f, y:%f, a:%f)", i, shadowVertices[i].x, 7577b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui shadowVertices[i].y, shadowVertices[i].alpha); 7587b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 7597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#endif 7607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 7617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 7637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * This is only for experimental purpose. 7647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * After intersections are calculated, we could smooth the polygon if needed. 7657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * So far, we don't think it is more appealing yet. 7667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 7677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param level The level of smoothness. 7687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param rays The total number of rays. 7697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param rayDist (In and Out) The distance for each ray. 7707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 7717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 7727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::smoothPolygon(int level, int rays, float* rayDist) { 7737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int k = 0; k < level; k++) { 7747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < rays; i++) { 7757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float p1 = rayDist[(rays - 1 + i) % rays]; 7767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float p2 = rayDist[i]; 7777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float p3 = rayDist[(i + 1) % rays]; 7787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui rayDist[i] = (p1 + p2 * 2 + p3) / 4; 7797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 7807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 7817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 7827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 7847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Calculate the number of vertex we will create given a number of rays and layers 7857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 7867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param rays number of points around the polygons you want 7877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param layers number of layers of triangle strips you need 7887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return number of vertex (multiply by 3 for number of floats) 7897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 790726118b35240957710d4d85fb5747e2ba8b934f7Chris Craikint SpotShadow::getStripSize(int rays) { 791726118b35240957710d4d85fb5747e2ba8b934f7Chris Craik return (2 + rays + (2 * (rays + 1))); 7927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 7937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 794f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui#if DEBUG_SHADOW 795f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 796f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui#define TEST_POINT_NUMBER 128 797f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 798f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui/** 799f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui * Calculate the bounds for generating random test points. 800f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui */ 801f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghuivoid SpotShadow::updateBound(const Vector2 inVector, Vector2& lowerBound, 802f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui Vector2& upperBound ) { 803f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui if (inVector.x < lowerBound.x) { 804f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui lowerBound.x = inVector.x; 805f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 806f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 807f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui if (inVector.y < lowerBound.y) { 808f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui lowerBound.y = inVector.y; 809f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 810f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 811f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui if (inVector.x > upperBound.x) { 812f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui upperBound.x = inVector.x; 813f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 814f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 815f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui if (inVector.y > upperBound.y) { 816f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui upperBound.y = inVector.y; 817f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 818f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui} 819f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 820f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui/** 821f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui * For debug purpose, when things go wrong, dump the whole polygon data. 822f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui */ 823f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghuistatic void dumpPolygon(const Vector2* poly, int polyLength, const char* polyName) { 824f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui for (int i = 0; i < polyLength; i++) { 825f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui ALOGD("polygon %s i %d x %f y %f", polyName, i, poly[i].x, poly[i].y); 826f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 827f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui} 828f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 829f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui/** 830f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui * Test whether the polygon is convex. 831f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui */ 832f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghuibool SpotShadow::testConvex(const Vector2* polygon, int polygonLength, 833f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui const char* name) { 834f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui bool isConvex = true; 835f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui for (int i = 0; i < polygonLength; i++) { 836f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui Vector2 start = polygon[i]; 837f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui Vector2 middle = polygon[(i + 1) % polygonLength]; 838f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui Vector2 end = polygon[(i + 2) % polygonLength]; 839f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 840f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui double delta = (double(middle.x) - start.x) * (double(end.y) - start.y) - 841f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui (double(middle.y) - start.y) * (double(end.x) - start.x); 842f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui bool isCCWOrCoLinear = (delta >= EPSILON); 843f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 844f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui if (isCCWOrCoLinear) { 845f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui ALOGE("(Error Type 2): polygon (%s) is not a convex b/c start (x %f, y %f)," 846f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui "middle (x %f, y %f) and end (x %f, y %f) , delta is %f !!!", 847f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui name, start.x, start.y, middle.x, middle.y, end.x, end.y, delta); 848f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui isConvex = false; 849f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui break; 850f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 851f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 852f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui return isConvex; 853f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui} 854f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 855f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui/** 856f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui * Test whether or not the polygon (intersection) is within the 2 input polygons. 857f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui * Using Marte Carlo method, we generate a random point, and if it is inside the 858f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui * intersection, then it must be inside both source polygons. 859f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui */ 860f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghuivoid SpotShadow::testIntersection(const Vector2* poly1, int poly1Length, 861f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui const Vector2* poly2, int poly2Length, 862f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui const Vector2* intersection, int intersectionLength) { 863f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui // Find the min and max of x and y. 864f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui Vector2 lowerBound(FLT_MAX, FLT_MAX); 865f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui Vector2 upperBound(-FLT_MAX, -FLT_MAX); 866f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui for (int i = 0; i < poly1Length; i++) { 867f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui updateBound(poly1[i], lowerBound, upperBound); 868f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 869f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui for (int i = 0; i < poly2Length; i++) { 870f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui updateBound(poly2[i], lowerBound, upperBound); 871f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 872f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 873f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui bool dumpPoly = false; 874f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui for (int k = 0; k < TEST_POINT_NUMBER; k++) { 875f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui // Generate a random point between minX, minY and maxX, maxY. 876f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui double randomX = rand() / double(RAND_MAX); 877f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui double randomY = rand() / double(RAND_MAX); 878f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 879f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui Vector2 testPoint; 880f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui testPoint.x = lowerBound.x + randomX * (upperBound.x - lowerBound.x); 881f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui testPoint.y = lowerBound.y + randomY * (upperBound.y - lowerBound.y); 882f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 883f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui // If the random point is in both poly 1 and 2, then it must be intersection. 884f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui if (testPointInsidePolygon(testPoint, intersection, intersectionLength)) { 885f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui if (!testPointInsidePolygon(testPoint, poly1, poly1Length)) { 886f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui dumpPoly = true; 887f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui ALOGE("(Error Type 1): one point (%f, %f) in the intersection is" 888f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui " not in the poly1", 889f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui testPoint.x, testPoint.y); 890f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 891f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 892f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui if (!testPointInsidePolygon(testPoint, poly2, poly2Length)) { 893f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui dumpPoly = true; 894f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui ALOGE("(Error Type 1): one point (%f, %f) in the intersection is" 895f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui " not in the poly2", 896f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui testPoint.x, testPoint.y); 897f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 898f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 899f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 900f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 901f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui if (dumpPoly) { 902f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui dumpPolygon(intersection, intersectionLength, "intersection"); 903f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui for (int i = 1; i < intersectionLength; i++) { 904f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui Vector2 delta = intersection[i] - intersection[i - 1]; 905f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui ALOGD("Intersetion i, %d Vs i-1 is delta %f", i, delta.lengthSquared()); 906f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 907f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 908f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui dumpPolygon(poly1, poly1Length, "poly 1"); 909f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui dumpPolygon(poly2, poly2Length, "poly 2"); 910f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui } 911f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui} 912f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui#endif 913f5ca8b4cb178008472e67fa0ae6a3e3fa75d7952ztenghui 9147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui}; // namespace uirenderer 9157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui}; // namespace android 916