1/* 2 * Copyright (C) 2013 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#define LOG_TAG "OpenGLRenderer" 18#define ATRACE_TAG ATRACE_TAG_VIEW 19 20#include <math.h> 21#include <utils/Log.h> 22#include <utils/Trace.h> 23 24#include "AmbientShadow.h" 25#include "Caches.h" 26#include "ShadowTessellator.h" 27#include "SpotShadow.h" 28 29namespace android { 30namespace uirenderer { 31 32void ShadowTessellator::tessellateAmbientShadow(bool isCasterOpaque, 33 const Vector3* casterPolygon, int casterVertexCount, 34 const Vector3& centroid3d, const Rect& casterBounds, 35 const Rect& localClip, float maxZ, VertexBuffer& shadowVertexBuffer) { 36 ATRACE_CALL(); 37 38 // A bunch of parameters to tweak the shadow. 39 // TODO: Allow some of these changable by debug settings or APIs. 40 float heightFactor = 1.0f / 128; 41 const float geomFactor = 64; 42 43 Caches& caches = Caches::getInstance(); 44 if (CC_UNLIKELY(caches.propertyAmbientRatio > 0.0f)) { 45 heightFactor *= caches.propertyAmbientRatio; 46 } 47 48 Rect ambientShadowBounds(casterBounds); 49 ambientShadowBounds.outset(maxZ * geomFactor * heightFactor); 50 51 if (!localClip.intersects(ambientShadowBounds)) { 52#if DEBUG_SHADOW 53 ALOGD("Ambient shadow is out of clip rect!"); 54#endif 55 return; 56 } 57 58 AmbientShadow::createAmbientShadow(isCasterOpaque, casterPolygon, 59 casterVertexCount, centroid3d, heightFactor, geomFactor, 60 shadowVertexBuffer); 61} 62 63void ShadowTessellator::tessellateSpotShadow(bool isCasterOpaque, 64 const Vector3* casterPolygon, int casterVertexCount, const Vector3& casterCentroid, 65 const mat4& receiverTransform, const Vector3& lightCenter, int lightRadius, 66 const Rect& casterBounds, const Rect& localClip, VertexBuffer& shadowVertexBuffer) { 67 ATRACE_CALL(); 68 69 Caches& caches = Caches::getInstance(); 70 71 Vector3 adjustedLightCenter(lightCenter); 72 if (CC_UNLIKELY(caches.propertyLightPosY > 0)) { 73 adjustedLightCenter.y = - caches.propertyLightPosY; // negated since this shifts up 74 } 75 if (CC_UNLIKELY(caches.propertyLightPosZ > 0)) { 76 adjustedLightCenter.z = caches.propertyLightPosZ; 77 } 78 79#if DEBUG_SHADOW 80 ALOGD("light center %f %f %f", 81 adjustedLightCenter.x, adjustedLightCenter.y, adjustedLightCenter.z); 82#endif 83 84 // light position (because it's in local space) needs to compensate for receiver transform 85 // TODO: should apply to light orientation, not just position 86 Matrix4 reverseReceiverTransform; 87 reverseReceiverTransform.loadInverse(receiverTransform); 88 reverseReceiverTransform.mapPoint3d(adjustedLightCenter); 89 90 const int lightVertexCount = 8; 91 if (CC_UNLIKELY(caches.propertyLightDiameter > 0)) { 92 lightRadius = caches.propertyLightDiameter; 93 } 94 95 // Now light and caster are both in local space, we will check whether 96 // the shadow is within the clip area. 97 Rect lightRect = Rect(adjustedLightCenter.x - lightRadius, adjustedLightCenter.y - lightRadius, 98 adjustedLightCenter.x + lightRadius, adjustedLightCenter.y + lightRadius); 99 lightRect.unionWith(localClip); 100 if (!lightRect.intersects(casterBounds)) { 101#if DEBUG_SHADOW 102 ALOGD("Spot shadow is out of clip rect!"); 103#endif 104 return; 105 } 106 107 SpotShadow::createSpotShadow(isCasterOpaque, adjustedLightCenter, lightRadius, 108 casterPolygon, casterVertexCount, casterCentroid, shadowVertexBuffer); 109 110#if DEBUG_SHADOW 111 if(shadowVertexBuffer.getVertexCount() <= 0) { 112 ALOGD("Spot shadow generation failed %d", shadowVertexBuffer.getVertexCount()); 113 } 114#endif 115} 116 117void ShadowTessellator::generateShadowIndices(uint16_t* shadowIndices) { 118 int currentIndex = 0; 119 const int rays = SHADOW_RAY_COUNT; 120 // For the penumbra area. 121 for (int layer = 0; layer < 2; layer ++) { 122 int baseIndex = layer * rays; 123 for (int i = 0; i < rays; i++) { 124 shadowIndices[currentIndex++] = i + baseIndex; 125 shadowIndices[currentIndex++] = rays + i + baseIndex; 126 } 127 // To close the loop, back to the ray 0. 128 shadowIndices[currentIndex++] = 0 + baseIndex; 129 // Note this is the same as the first index of next layer loop. 130 shadowIndices[currentIndex++] = rays + baseIndex; 131 } 132 133#if DEBUG_SHADOW 134 if (currentIndex != MAX_SHADOW_INDEX_COUNT) { 135 ALOGW("vertex index count is wrong. current %d, expected %d", 136 currentIndex, MAX_SHADOW_INDEX_COUNT); 137 } 138 for (int i = 0; i < MAX_SHADOW_INDEX_COUNT; i++) { 139 ALOGD("vertex index is (%d, %d)", i, shadowIndices[i]); 140 } 141#endif 142} 143 144/** 145 * Calculate the centroid of a 2d polygon. 146 * 147 * @param poly The polygon, which is represented in a Vector2 array. 148 * @param polyLength The length of the polygon in terms of number of vertices. 149 * @return the centroid of the polygon. 150 */ 151Vector2 ShadowTessellator::centroid2d(const Vector2* poly, int polyLength) { 152 double sumx = 0; 153 double sumy = 0; 154 int p1 = polyLength - 1; 155 double area = 0; 156 for (int p2 = 0; p2 < polyLength; p2++) { 157 double x1 = poly[p1].x; 158 double y1 = poly[p1].y; 159 double x2 = poly[p2].x; 160 double y2 = poly[p2].y; 161 double a = (x1 * y2 - x2 * y1); 162 sumx += (x1 + x2) * a; 163 sumy += (y1 + y2) * a; 164 area += a; 165 p1 = p2; 166 } 167 168 Vector2 centroid = poly[0]; 169 if (area != 0) { 170 centroid = (Vector2){static_cast<float>(sumx / (3 * area)), 171 static_cast<float>(sumy / (3 * area))}; 172 } else { 173 ALOGW("Area is 0 while computing centroid!"); 174 } 175 return centroid; 176} 177 178// Make sure p1 -> p2 is going CW around the poly. 179Vector2 ShadowTessellator::calculateNormal(const Vector2& p1, const Vector2& p2) { 180 Vector2 result = p2 - p1; 181 if (result.x != 0 || result.y != 0) { 182 result.normalize(); 183 // Calculate the normal , which is CCW 90 rotate to the delta. 184 float tempy = result.y; 185 result.y = result.x; 186 result.x = -tempy; 187 } 188 return result; 189} 190/** 191 * Test whether the polygon is order in clockwise. 192 * 193 * @param polygon the polygon as a Vector2 array 194 * @param len the number of points of the polygon 195 */ 196bool ShadowTessellator::isClockwise(const Vector2* polygon, int len) { 197 if (len < 2 || polygon == NULL) { 198 return true; 199 } 200 double sum = 0; 201 double p1x = polygon[len - 1].x; 202 double p1y = polygon[len - 1].y; 203 for (int i = 0; i < len; i++) { 204 205 double p2x = polygon[i].x; 206 double p2y = polygon[i].y; 207 sum += p1x * p2y - p2x * p1y; 208 p1x = p2x; 209 p1y = p2y; 210 } 211 return sum < 0; 212} 213 214bool ShadowTessellator::isClockwisePath(const SkPath& path) { 215 SkPath::Iter iter(path, false); 216 SkPoint pts[4]; 217 SkPath::Verb v; 218 219 Vector<Vector2> arrayForDirection; 220 while (SkPath::kDone_Verb != (v = iter.next(pts))) { 221 switch (v) { 222 case SkPath::kMove_Verb: 223 arrayForDirection.add((Vector2){pts[0].x(), pts[0].y()}); 224 break; 225 case SkPath::kLine_Verb: 226 arrayForDirection.add((Vector2){pts[1].x(), pts[1].y()}); 227 break; 228 case SkPath::kQuad_Verb: 229 arrayForDirection.add((Vector2){pts[1].x(), pts[1].y()}); 230 arrayForDirection.add((Vector2){pts[2].x(), pts[2].y()}); 231 break; 232 case SkPath::kCubic_Verb: 233 arrayForDirection.add((Vector2){pts[1].x(), pts[1].y()}); 234 arrayForDirection.add((Vector2){pts[2].x(), pts[2].y()}); 235 arrayForDirection.add((Vector2){pts[3].x(), pts[3].y()}); 236 break; 237 default: 238 break; 239 } 240 } 241 242 return isClockwise(arrayForDirection.array(), arrayForDirection.size()); 243} 244 245void ShadowTessellator::reverseVertexArray(Vertex* polygon, int len) { 246 int n = len / 2; 247 for (int i = 0; i < n; i++) { 248 Vertex tmp = polygon[i]; 249 int k = len - 1 - i; 250 polygon[i] = polygon[k]; 251 polygon[k] = tmp; 252 } 253} 254 255int ShadowTessellator::getExtraVertexNumber(const Vector2& vector1, 256 const Vector2& vector2, float divisor) { 257 // When there is no distance difference, there is no need for extra vertices. 258 if (vector1.lengthSquared() == 0 || vector2.lengthSquared() == 0) { 259 return 0; 260 } 261 // The formula is : 262 // extraNumber = floor(acos(dot(n1, n2)) / (M_PI / EXTRA_VERTEX_PER_PI)) 263 // The value ranges for each step are: 264 // dot( ) --- [-1, 1] 265 // acos( ) --- [0, M_PI] 266 // floor(...) --- [0, EXTRA_VERTEX_PER_PI] 267 float dotProduct = vector1.dot(vector2); 268 // TODO: Use look up table for the dotProduct to extraVerticesNumber 269 // computation, if needed. 270 float angle = acosf(dotProduct); 271 return (int) floor(angle / divisor); 272} 273 274void ShadowTessellator::checkOverflow(int used, int total, const char* bufferName) { 275 LOG_ALWAYS_FATAL_IF(used > total, "Error: %s overflow!!! used %d, total %d", 276 bufferName, used, total); 277} 278 279}; // namespace uirenderer 280}; // namespace android 281