SpotShadow.cpp revision 7b4516e7ea552ad08d6e7277d311ef11bd8f12e8
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> 227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#include <utils/Log.h> 237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#include "SpotShadow.h" 257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#include "Vertex.h" 267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuinamespace android { 287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuinamespace uirenderer { 297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Calculate the intersection of a ray with a polygon. 327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * It assumes the ray originates inside the polygon. 337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly The polygon, which is represented in a Vector2 array. 357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param polyLength The length of caster's polygon in terms of number of 367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * vertices. 377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param point the start of the ray 387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param dx the x vector of the ray 397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param dy the y vector of the ray 407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return the distance along the ray if it intersects with the polygon FP_NAN if otherwise 417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuifloat SpotShadow::rayIntersectPoly(const Vector2* poly, int polyLength, 437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui const Vector2& point, float dx, float dy) { 447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double px = point.x; 457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double py = point.y; 467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int p1 = polyLength - 1; 477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int p2 = 0; p2 < polyLength; p2++) { 487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double p1x = poly[p1].x; 497b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double p1y = poly[p1].y; 507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double p2x = poly[p2].x; 517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double p2y = poly[p2].y; 527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // The math below is derived from solving this formula, basically the 537b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // intersection point should stay on both the ray and the edge of (p1, p2). 547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // solve([p1x+t*(p2x-p1x)=dx*t2+px,p1y+t*(p2y-p1y)=dy*t2+py],[t,t2]); 557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double div = (dx * (p1y - p2y) + dy * p2x - dy * p1x); 567b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (div != 0) { 577b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double t = (dx * (p1y - py) + dy * px - dy * p1x) / (div); 587b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (t >= 0 && t <= 1) { 597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double t2 = (p1x * (py - p2y) + p2x * (p1y - py) + 607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui px * (p2y - p1y)) / div; 617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (t2 > 0) { 627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return (float)t2; 637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui p1 = p2; 677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return FP_NAN; 697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Calculate the centroid of a 2d polygon. 737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly The polygon, which is represented in a Vector2 array. 757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param polyLength The length of the polygon in terms of number of vertices. 767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return the centroid of the polygon. 777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuiVector2 SpotShadow::centroid2d(const Vector2* poly, int polyLength) { 797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double sumx = 0; 807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double sumy = 0; 817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int p1 = polyLength - 1; 827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double area = 0; 837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int p2 = 0; p2 < polyLength; p2++) { 847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double x1 = poly[p1].x; 857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double y1 = poly[p1].y; 867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double x2 = poly[p2].x; 877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double y2 = poly[p2].y; 887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double a = (x1 * y2 - x2 * y1); 897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui sumx += (x1 + x2) * a; 907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui sumy += (y1 + y2) * a; 917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui area += a; 927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui p1 = p2; 937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double centroidx = sumx / (3 * area); 967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double centroidy = sumy / (3 * area); 977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return Vector2((float)centroidx, (float)centroidy); 987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 1017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Sort points by their X coordinates 1027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 1037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param points the points as a Vector2 array. 1047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param pointsLength the number of vertices of the polygon. 1057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 1067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::xsort(Vector2* points, int pointsLength) { 1077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui quicksortX(points, 0, pointsLength - 1); 1087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 1097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 1117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * compute the convex hull of a collection of Points 1127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 1137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param points the points as a Vector2 array. 1147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param pointsLength the number of vertices of the polygon. 1157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param retPoly pre allocated array of floats to put the vertices 1167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return the number of points in the polygon 0 if no intersection 1177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 1187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuiint SpotShadow::hull(Vector2* points, int pointsLength, Vector2* retPoly) { 1197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui xsort(points, pointsLength); 1207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int n = pointsLength; 1217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 lUpper[n]; 1227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpper[0] = points[0]; 1237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpper[1] = points[1]; 1247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int lUpperSize = 2; 1267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 2; i < n; i++) { 1287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpper[lUpperSize] = points[i]; 1297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpperSize++; 1307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui while (lUpperSize > 2 && !rightTurn( 1327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui (double)lUpper[lUpperSize - 3].x, (double)lUpper[lUpperSize - 3].y, 1337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui (double)lUpper[lUpperSize - 2].x, (double)lUpper[lUpperSize - 2].y, 1347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui (double)lUpper[lUpperSize - 1].x, (double)lUpper[lUpperSize - 1].y)) { 1357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Remove the middle point of the three last 1367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpper[lUpperSize - 2].x = lUpper[lUpperSize - 1].x; 1377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpper[lUpperSize - 2].y = lUpper[lUpperSize - 1].y; 1387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lUpperSize--; 1397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 lLower[n]; 1437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lLower[0] = points[n - 1]; 1447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lLower[1] = points[n - 2]; 1457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int lLowerSize = 2; 1477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = n - 3; i >= 0; i--) { 1497b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lLower[lLowerSize] = points[i]; 1507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lLowerSize++; 1517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui while (lLowerSize > 2 && !rightTurn( 1537b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui (double)lLower[lLowerSize - 3].x, (double)lLower[lLowerSize - 3].y, 1547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui (double)lLower[lLowerSize - 2].x, (double)lLower[lLowerSize - 2].y, 1557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui (double)lLower[lLowerSize - 1].x, (double)lLower[lLowerSize - 1].y)) { 1567b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Remove the middle point of the three last 1577b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lLower[lLowerSize - 2] = lLower[lLowerSize - 1]; 1587b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui lLowerSize--; 1597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int count = 0; 1627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < lUpperSize; i++) { 1647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui retPoly[count] = lUpper[i]; 1657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui count++; 1667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 1; i < lLowerSize - 1; i++) { 1697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui retPoly[count] = lLower[i]; 1707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui count++; 1717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 1727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // TODO: Add test harness which verify that all the points are inside the hull. 1737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return count; 1747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 1757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 1777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Test whether the 3 points form a right hand turn 1787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 1797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param ax the x coordinate of point a 1807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param ay the y coordinate of point a 1817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param bx the x coordinate of point b 1827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param by the y coordinate of point b 1837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param cx the x coordinate of point c 1847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param cy the y coordinate of point c 1857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return true if a right hand turn 1867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 1877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuibool SpotShadow::rightTurn(double ax, double ay, double bx, double by, 1887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double cx, double cy) { 1897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return (bx - ax) * (cy - ay) - (by - ay) * (cx - ax) > EPSILON; 1907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 1917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 1927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 1937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Calculates the intersection of poly1 with poly2 and put in poly2. 1947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 1957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 1967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly1 The 1st polygon, as a Vector2 array. 1977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly1Length The number of vertices of 1st polygon. 1987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly2 The 2nd and output polygon, as a Vector2 array. 1997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly2Length The number of vertices of 2nd polygon. 2007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return number of vertices in output polygon as poly2. 2017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 2027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuiint SpotShadow::intersection(Vector2* poly1, int poly1Length, 2037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2* poly2, int poly2Length) { 2047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui makeClockwise(poly1, poly1Length); 2057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui makeClockwise(poly2, poly2Length); 2067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 poly[poly1Length * poly2Length + 2]; 2077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int count = 0; 2087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int pcount = 0; 2097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // If one vertex from one polygon sits inside another polygon, add it and 2117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // count them. 2127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < poly1Length; i++) { 2137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (testPointInsidePolygon(poly1[i], poly2, poly2Length)) { 2147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly[count] = poly1[i]; 2157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui count++; 2167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui pcount++; 2177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int insidePoly2 = pcount; 2227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < poly2Length; i++) { 2237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (testPointInsidePolygon(poly2[i], poly1, poly1Length)) { 2247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly[count] = poly2[i]; 2257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui count++; 2267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int insidePoly1 = count - insidePoly2; 2307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // If all vertices from poly1 are inside poly2, then just return poly1. 2317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (insidePoly2 == poly1Length) { 2327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui memcpy(poly2, poly1, poly1Length * sizeof(Vector2)); 2337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return poly1Length; 2347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // If all vertices from poly2 are inside poly1, then just return poly2. 2377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (insidePoly1 == poly2Length) { 2387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return poly2Length; 2397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Since neither polygon fully contain the other one, we need to add all the 2427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // intersection points. 2437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 intersection; 2447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < poly2Length; i++) { 2457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int j = 0; j < poly1Length; j++) { 2467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int poly2LineStart = i; 2477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int poly2LineEnd = ((i + 1) % poly2Length); 2487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int poly1LineStart = j; 2497b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int poly1LineEnd = ((j + 1) % poly1Length); 2507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui bool found = lineIntersection( 2517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly2[poly2LineStart].x, poly2[poly2LineStart].y, 2527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly2[poly2LineEnd].x, poly2[poly2LineEnd].y, 2537b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly1[poly1LineStart].x, poly1[poly1LineStart].y, 2547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly1[poly1LineEnd].x, poly1[poly1LineEnd].y, 2557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui intersection); 2567b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (found) { 2577b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly[count].x = intersection.x; 2587b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly[count].y = intersection.y; 2597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui count++; 2607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } else { 2617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 delta = poly2[i] - poly1[j]; 2627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (delta.lengthSquared() < 0.01) { 2637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly[count] = poly2[i]; 2647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui count++; 2657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (count == 0) { 2717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return 0; 2727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Sort the result polygon around the center. 2757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 center(0.0f, 0.0f); 2767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < count; i++) { 2777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui center += poly[i]; 2787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui center /= count; 2807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui sort(poly, count, center); 2817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // TODO: Verify the intersection works correctly, like any random point 2837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // inside both poly1 and poly2 should be inside the intersection, and the 2847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // result intersection polygon is convex. 2857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Merge the vertices if they are too close. 2877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly2[0] = poly[0]; 2887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int resultLength = 1; 2897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 1; i < count; i++) { 2907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 delta = poly[i] - poly[i - 1]; 2917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (delta.lengthSquared() >= 0.01) { 2927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly2[resultLength] = poly[i]; 2937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui resultLength++; 2947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 2967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 2977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return resultLength; 2987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 2997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 3017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Sort points about a center point 3027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 3037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly The in and out polyogon as a Vector2 array. 3047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param polyLength The number of vertices of the polygon. 3057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param center the center ctr[0] = x , ctr[1] = y to sort around. 3067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 3077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::sort(Vector2* poly, int polyLength, const Vector2& center) { 3087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui quicksortCirc(poly, 0, polyLength - 1, center); 3097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 3107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 3127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Calculate the angle between and x and a y coordinate 3137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 3147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuifloat SpotShadow::angle(const Vector2& point, const Vector2& center) { 3157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return -(float)atan2(point.x - center.x, point.y - center.y); 3167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 3177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 3197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Swap points pointed to by i and j 3207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 3217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::swap(Vector2* points, int i, int j) { 3227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 temp = points[i]; 3237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui points[i] = points[j]; 3247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui points[j] = temp; 3257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 3267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 3287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * quick sort implementation about the center. 3297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 3307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::quicksortCirc(Vector2* points, int low, int high, 3317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui const Vector2& center) { 3327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int i = low, j = high; 3337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int p = low + (high - low) / 2; 3347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float pivot = angle(points[p], center); 3357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui while (i <= j) { 3367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui while (angle(points[i], center) < pivot) { 3377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui i++; 3387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui while (angle(points[j], center) > pivot) { 3407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui j--; 3417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (i <= j) { 3447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui swap(points, i, j); 3457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui i++; 3467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui j--; 3477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3497b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (low < j) quicksortCirc(points, low, j, center); 3507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (i < high) quicksortCirc(points, i, high, center); 3517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 3527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3537b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 3547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Sort points by x axis 3557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 3567b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param points points to sort 3577b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param low start index 3587b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param high end index 3597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 3607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::quicksortX(Vector2* points, int low, int high) { 3617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int i = low, j = high; 3627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int p = low + (high - low) / 2; 3637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float pivot = points[p].x; 3647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui while (i <= j) { 3657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui while (points[i].x < pivot) { 3667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui i++; 3677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui while (points[j].x > pivot) { 3697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui j--; 3707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (i <= j) { 3737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui swap(points, i, j); 3747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui i++; 3757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui j--; 3767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 3787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (low < j) quicksortX(points, low, j); 3797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (i < high) quicksortX(points, i, high); 3807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 3817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 3827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 3837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Test whether a point is inside the polygon. 3847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 3857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param testPoint the point to test 3867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly the polygon 3877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return true if the testPoint is inside the poly. 3887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 3897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuibool SpotShadow::testPointInsidePolygon(const Vector2 testPoint, 3907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui const Vector2* poly, int len) { 3917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui bool c = false; 3927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double testx = testPoint.x; 3937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double testy = testPoint.y; 3947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0, j = len - 1; i < len; j = i++) { 3957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double startX = poly[j].x; 3967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double startY = poly[j].y; 3977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double endX = poly[i].x; 3987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double endY = poly[i].y; 3997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (((endY > testy) != (startY > testy)) && 4017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui (testx < (startX - endX) * (testy - endY) 4027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui / (startY - endY) + endX)) { 4037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui c = !c; 4047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 4057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 4067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return c; 4077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 4087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 4107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Make the polygon turn clockwise. 4117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 4127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param polygon the polygon as a Vector2 array. 4137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param len the number of points of the polygon 4147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 4157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::makeClockwise(Vector2* polygon, int len) { 4167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (polygon == 0 || len == 0) { 4177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return; 4187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 4197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (!isClockwise(polygon, len)) { 4207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui reverse(polygon, len); 4217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 4227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 4237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 4257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Test whether the polygon is order in clockwise. 4267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 4277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param polygon the polygon as a Vector2 array 4287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param len the number of points of the polygon 4297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 4307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuibool SpotShadow::isClockwise(Vector2* polygon, int len) { 4317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double sum = 0; 4327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double p1x = polygon[len - 1].x; 4337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double p1y = polygon[len - 1].y; 4347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < len; i++) { 4357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double p2x = polygon[i].x; 4377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double p2y = polygon[i].y; 4387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui sum += p1x * p2y - p2x * p1y; 4397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui p1x = p2x; 4407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui p1y = p2y; 4417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 4427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return sum < 0; 4437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 4447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 4467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Reverse the polygon 4477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 4487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param polygon the polygon as a Vector2 array 4497b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param len the number of points of the polygon 4507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 4517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::reverse(Vector2* polygon, int len) { 4527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int n = len / 2; 4537b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < n; i++) { 4547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 tmp = polygon[i]; 4557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int k = len - 1 - i; 4567b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui polygon[i] = polygon[k]; 4577b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui polygon[k] = tmp; 4587b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 4597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 4607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 4627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Intersects two lines in parametric form. This function is called in a tight 4637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * loop, and we need double precision to get things right. 4647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 4657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param x1 the x coordinate point 1 of line 1 4667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param y1 the y coordinate point 1 of line 1 4677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param x2 the x coordinate point 2 of line 1 4687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param y2 the y coordinate point 2 of line 1 4697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param x3 the x coordinate point 1 of line 2 4707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param y3 the y coordinate point 1 of line 2 4717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param x4 the x coordinate point 2 of line 2 4727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param y4 the y coordinate point 2 of line 2 4737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param ret the x,y location of the intersection 4747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return true if it found an intersection 4757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 4767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuiinline bool SpotShadow::lineIntersection(double x1, double y1, double x2, double y2, 4777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double x3, double y3, double x4, double y4, Vector2& ret) { 4787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double d = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4); 4797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (d == 0.0) return false; 4807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double dx = (x1 * y2 - y1 * x2); 4827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double dy = (x3 * y4 - y3 * x4); 4837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double x = (dx * (x3 - x4) - (x1 - x2) * dy) / d; 4847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double y = (dx * (y3 - y4) - (y1 - y2) * dy) / d; 4857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // The intersection should be in the middle of the point 1 and point 2, 4877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // likewise point 3 and point 4. 4887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (((x - x1) * (x - x2) > EPSILON) 4897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui || ((x - x3) * (x - x4) > EPSILON) 4907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui || ((y - y1) * (y - y2) > EPSILON) 4917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui || ((y - y3) * (y - y4) > EPSILON)) { 4927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Not interesected 4937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return false; 4947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 4957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ret.x = x; 4967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ret.y = y; 4977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return true; 4987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 4997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 5007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 5027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Compute a horizontal circular polygon about point (x , y , height) of radius 5037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * (size) 5047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 5057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param points number of the points of the output polygon. 5067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param lightCenter the center of the light. 5077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param size the light size. 5087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param ret result polygon. 5097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 5107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::computeLightPolygon(int points, const Vector3& lightCenter, 5117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float size, Vector3* ret) { 5127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // TODO: Caching all the sin / cos values and store them in a look up table. 5137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < points; i++) { 5147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui double angle = 2 * i * M_PI / points; 5157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ret[i].x = sinf(angle) * size + lightCenter.x; 5167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ret[i].y = cosf(angle) * size + lightCenter.y; 5177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ret[i].z = lightCenter.z; 5187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 5207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 5227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* Generate the shadow from a spot light. 5237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* 5247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param poly x,y,z vertexes of a convex polygon that occludes the light source 5257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param polyLength number of vertexes of the occluding polygon 5267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param lightCenter the center of the light 5277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param lightSize the radius of the light source 5287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param lightVertexCount the vertex counter for the light polygon 5297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param rays the number of vertexes to create along the edges of the shadow 5307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param layers the number of layers of triangles strips to create 5317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param strength the "darkness" of the shadow 5327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* @param shadowTriangleStrip return an (x,y,alpha) triangle strip representing the shadow. Return 5337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* empty strip if error. 5347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui* 5357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui*/ 5367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::createSpotShadow(const Vector3* poly, int polyLength, 5377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui const Vector3& lightCenter, float lightSize, int lightVertexCount, 5387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int rays, int layers, float strength, VertexBuffer& retStrips) { 5397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector3 light[lightVertexCount * 3]; 5407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui computeLightPolygon(lightVertexCount, lightCenter, lightSize, light); 5417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui computeSpotShadow(light, lightVertexCount, lightCenter, 5427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui poly, polyLength, rays, layers, strength, retStrips); 5437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 5447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 5467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Generate the shadow spot light of shape lightPoly and a object poly 5477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 5487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param lightPoly x,y,z vertex of a convex polygon that is the light source 5497b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param lightPolyLength number of vertexes of the light source polygon 5507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param poly x,y,z vertexes of a convex polygon that occludes the light source 5517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param polyLength number of vertexes of the occluding polygon 5527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param rays the number of vertexes to create along the edges of the shadow 5537b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param layers the number of layers of triangles strips to create 5547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param strength the "darkness" of the shadow 5557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param shadowTriangleStrip return an (x,y,alpha) triangle strip representing the shadow. Return 5567b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * empty strip if error. 5577b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 5587b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::computeSpotShadow(const Vector3* lightPoly, int lightPolyLength, 5597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui const Vector3& lightCenter, const Vector3* poly, int polyLength, 5607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int rays, int layers, float strength, VertexBuffer& shadowTriangleStrip) { 5617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Point clouds for all the shadowed vertices 5627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 shadowRegion[lightPolyLength * polyLength]; 5637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Shadow polygon from one point light. 5647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 outline[polyLength]; 5657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 umbraMem[polyLength * lightPolyLength]; 5667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2* umbra = umbraMem; 5677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int umbraLength = 0; 5697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Validate input, receiver is always at z = 0 plane. 5717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui bool inputPolyPositionValid = true; 5727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < polyLength; i++) { 5737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (poly[i].z <= 0.00001) { 5747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui inputPolyPositionValid = false; 5757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ALOGE("polygon below the surface"); 5767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui break; 5777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (poly[i].z >= lightPoly[0].z) { 5797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui inputPolyPositionValid = false; 5807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ALOGE("polygon above the light"); 5817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui break; 5827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // If the caster's position is invalid, don't draw anything. 5867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (!inputPolyPositionValid) { 5877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return; 5887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 5907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Calculate the umbra polygon based on intersections of all outlines 5917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int k = 0; 5927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int j = 0; j < lightPolyLength; j++) { 5937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int m = 0; 5947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < polyLength; i++) { 5957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float t = lightPoly[j].z - poly[i].z; 5967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (t == 0) { 5977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return; 5987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 5997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui t = lightPoly[j].z / t; 6007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float x = lightPoly[j].x - t * (lightPoly[j].x - poly[i].x); 6017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float y = lightPoly[j].y - t * (lightPoly[j].y - poly[i].y); 6027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 newPoint = Vector2(x, y); 6047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui shadowRegion[k] = newPoint; 6057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui outline[m] = newPoint; 6067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui k++; 6087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui m++; 6097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // For the first light polygon's vertex, use the outline as the umbra. 6127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Later on, use the intersection of the outline and existing umbra. 6137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (umbraLength == 0) { 6147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < polyLength; i++) { 6157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui umbra[i] = outline[i]; 6167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui umbraLength = polyLength; 6187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } else { 6197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int col = ((j * 255) / lightPolyLength); 6207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui umbraLength = intersection(outline, polyLength, umbra, umbraLength); 6217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (umbraLength == 0) { 6227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui break; 6237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Generate the penumbra area using the hull of all shadow regions. 6287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int shadowRegionLength = k; 6297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 penumbra[k]; 6307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int penumbraLength = hull(shadowRegion, shadowRegionLength, penumbra); 6317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // no real umbra make a fake one 6337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (umbraLength < 3) { 6347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // The shadow from the centroid of the light polygon. 6357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 centShadow[polyLength]; 6367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < polyLength; i++) { 6387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float t = lightCenter.z - poly[i].z; 6397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (t == 0) { 6407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return; 6417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui t = lightCenter.z / t; 6437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float x = lightCenter.x - t * (lightCenter.x - poly[i].x); 6447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float y = lightCenter.y - t * (lightCenter.y - poly[i].y); 6457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui centShadow[i].x = x; 6477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui centShadow[i].y = y; 6487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6497b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Shrink the centroid's shadow by 10%. 6517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // TODO: Study the magic number of 10%. 6527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 shadowCentroid = centroid2d(centShadow, polyLength); 6537b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < polyLength; i++) { 6547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui centShadow[i] = shadowCentroid * (1.0f - SHADOW_SHRINK_SCALE) + 6557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui centShadow[i] * SHADOW_SHRINK_SCALE; 6567b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6577b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#if DEBUG_SHADOW 6587b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ALOGD("No real umbra make a fake one, centroid2d = %f , %f", 6597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui shadowCentroid.x, shadowCentroid.y); 6607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#endif 6617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Set the fake umbra, whose size is the same as the original polygon. 6627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui umbra = centShadow; 6637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui umbraLength = polyLength; 6647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 6657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui generateTriangleStrip(penumbra, penumbraLength, umbra, umbraLength, 6677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui rays, layers, strength, shadowTriangleStrip); 6687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 6697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 6717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Generate a triangle strip given two convex polygons 6727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 6737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param penumbra The outer polygon x,y vertexes 6747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param penumbraLength The number of vertexes in the outer polygon 6757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param umbra The inner outer polygon x,y vertexes 6767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param umbraLength The number of vertexes in the inner polygon 6777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param rays The number of points along the polygons to create 6787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param layers The number of layers of triangle strips between the umbra and penumbra 6797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param strength The max alpha of the umbra 6807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param shadowTriangleStrip return an (x,y,alpha) triangle strip representing the shadow. Return 6817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * empty strip if error. 6827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui**/ 6837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::generateTriangleStrip(const Vector2* penumbra, int penumbraLength, 6847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui const Vector2* umbra, int umbraLength, int rays, int layers, 6857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float strength, VertexBuffer& shadowTriangleStrip) { 6867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int rings = layers + 1; 6887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int size = rays * rings; 6897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 6907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float step = M_PI * 2 / rays; 6917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Centroid of the umbra. 6927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui Vector2 centroid = centroid2d(umbra, umbraLength); 6937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#if DEBUG_SHADOW 6947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ALOGD("centroid2d = %f , %f", centroid.x, centroid.y); 6957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#endif 6967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Intersection to the penumbra. 6977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float penumbraDistPerRay[rays]; 6987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Intersection to the umbra. 6997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float umbraDistPerRay[rays]; 7007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < rays; i++) { 7027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // TODO: Setup a lookup table for all the sin/cos. 7037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float dx = sinf(step * i); 7047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float dy = cosf(step * i); 7057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui umbraDistPerRay[i] = rayIntersectPoly(umbra, umbraLength, centroid, 7067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui dx, dy); 7077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (isnan(umbraDistPerRay[i])) { 7087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ALOGE("rayIntersectPoly returns NAN"); 7097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return; 7107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 7117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui penumbraDistPerRay[i] = rayIntersectPoly(penumbra, penumbraLength, 7127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui centroid, dx, dy); 7137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if (isnan(umbraDistPerRay[i])) { 7147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ALOGE("rayIntersectPoly returns NAN"); 7157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return; 7167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 7177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 7187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int stripSize = getStripSize(rays, layers); 7207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui AlphaVertex* shadowVertices = shadowTriangleStrip.alloc<AlphaVertex>(stripSize); 7217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int currentIndex = 0; 7227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Calculate the vertex values in the penumbra area. 7237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int r = 0; r < layers; r++) { 7247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int firstInEachLayer = currentIndex; 7257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < rays; i++) { 7267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float dx = sinf(step * i); 7277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float dy = cosf(step * i); 7287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int j = r; j < (r + 2); j++) { 7307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float layerRatio = j / (float)(rings - 1); 7317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float deltaDist = layerRatio * (umbraDistPerRay[i] - penumbraDistPerRay[i]); 7327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float currentDist = penumbraDistPerRay[i] + deltaDist; 7337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float op = calculateOpacity(layerRatio, deltaDist); 7347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui AlphaVertex::set(&shadowVertices[currentIndex], 7357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui dx * currentDist + centroid.x, 7367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui dy * currentDist + centroid.y, 7377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui layerRatio * op * strength); 7387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui currentIndex++; 7397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 7407b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 7417b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7427b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Duplicate the vertices from one layer to another one to make triangle 7437b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // strip. 7447b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui shadowVertices[currentIndex++] = shadowVertices[firstInEachLayer]; 7457b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui firstInEachLayer++; 7467b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui shadowVertices[currentIndex++] = shadowVertices[firstInEachLayer]; 7477b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 7487b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7497b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int lastInPenumbra = currentIndex - 1; 7507b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui shadowVertices[currentIndex++] = shadowVertices[lastInPenumbra]; 7517b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7527b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Preallocate the vertices (index as [firstInUmbra - 1]) for jumping from 7537b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // the penumbra to umbra. 7547b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui currentIndex++; 7557b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int firstInUmbra = currentIndex; 7567b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7577b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // traverse the umbra area in a zig zag pattern for strips. 7587b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int k = 0; k < rays; k++) { 7597b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui int i = k / 2; 7607b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui if ((k & 1) == 1) { 7617b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui i = rays - i - 1; 7627b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 7637b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float dx = sinf(step * i); 7647b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float dy = cosf(step * i); 7657b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7667b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float ratio = 1.0; 7677b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float deltaDist = ratio * (umbraDistPerRay[i] - penumbraDistPerRay[i]); 7687b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float currentDist = penumbraDistPerRay[i] + deltaDist; 7697b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float op = calculateOpacity(ratio, deltaDist); 7707b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui AlphaVertex::set(&shadowVertices[currentIndex], 7717b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui dx * currentDist + centroid.x, dy * currentDist + centroid.y, 7727b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ratio * op * strength); 7737b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui currentIndex++; 7747b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7757b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 7767b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7777b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // Back fill the one vertex for jumping from penumbra to umbra. 7787b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui shadowVertices[firstInUmbra - 1] = shadowVertices[firstInUmbra]; 7797b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7807b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#if DEBUG_SHADOW 7817b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < currentIndex; i++) { 7827b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui ALOGD("shadow value: i %d, (x:%f, y:%f, a:%f)", i, shadowVertices[i].x, 7837b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui shadowVertices[i].y, shadowVertices[i].alpha); 7847b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 7857b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui#endif 7867b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 7877b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 7887b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 7897b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * This is only for experimental purpose. 7907b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * After intersections are calculated, we could smooth the polygon if needed. 7917b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * So far, we don't think it is more appealing yet. 7927b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 7937b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param level The level of smoothness. 7947b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param rays The total number of rays. 7957b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param rayDist (In and Out) The distance for each ray. 7967b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 7977b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 7987b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuivoid SpotShadow::smoothPolygon(int level, int rays, float* rayDist) { 7997b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int k = 0; k < level; k++) { 8007b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui for (int i = 0; i < rays; i++) { 8017b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float p1 = rayDist[(rays - 1 + i) % rays]; 8027b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float p2 = rayDist[i]; 8037b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float p3 = rayDist[(i + 1) % rays]; 8047b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui rayDist[i] = (p1 + p2 * 2 + p3) / 4; 8057b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 8067b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui } 8077b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 8087b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 8097b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 8107b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Calculate the opacity according to the distance and falloff ratio. 8117b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 8127b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param distRatio The distance ratio of current sample between umbra and 8137b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * penumbra area. 8147b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param deltaDist The distance between current sample to the penumbra area. 8157b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return The opacity according to the distance between umbra and penumbra. 8167b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 8177b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuifloat SpotShadow::calculateOpacity(float distRatio, float deltaDist) { 8187b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui // TODO: Experiment on the opacity calculation. 8197b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui float falloffRatio = 1 + deltaDist * deltaDist; 8207b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return (distRatio + 1 - 1 / falloffRatio) / 2; 8217b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 8227b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 8237b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui/** 8247b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * Calculate the number of vertex we will create given a number of rays and layers 8257b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * 8267b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param rays number of points around the polygons you want 8277b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @param layers number of layers of triangle strips you need 8287b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui * @return number of vertex (multiply by 3 for number of floats) 8297b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui */ 8307b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghuiint SpotShadow::getStripSize(int rays, int layers) { 8317b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui return (2 + rays + ((layers) * 2 * (rays + 1))); 8327b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui} 8337b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 8347b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui}; // namespace uirenderer 8357b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui}; // namespace android 8367b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 8377b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 8387b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 8397b4516e7ea552ad08d6e7277d311ef11bd8f12e8ztenghui 840