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#include <utils/Vector.h> 24#include <utils/MathUtils.h> 25 26#include "AmbientShadow.h" 27#include "Properties.h" 28#include "ShadowTessellator.h" 29#include "SpotShadow.h" 30#include "Vector.h" 31 32namespace android { 33namespace uirenderer { 34 35void ShadowTessellator::tessellateAmbientShadow(bool isCasterOpaque, 36 const Vector3* casterPolygon, int casterVertexCount, 37 const Vector3& centroid3d, const Rect& casterBounds, 38 const Rect& localClip, float maxZ, VertexBuffer& shadowVertexBuffer) { 39 ATRACE_CALL(); 40 41 // A bunch of parameters to tweak the shadow. 42 // TODO: Allow some of these changable by debug settings or APIs. 43 float heightFactor = 1.0f / 128; 44 const float geomFactor = 64; 45 46 if (CC_UNLIKELY(Properties::overrideAmbientRatio > 0.0f)) { 47 heightFactor *= Properties::overrideAmbientRatio; 48 } 49 50 Rect ambientShadowBounds(casterBounds); 51 ambientShadowBounds.outset(maxZ * geomFactor * heightFactor); 52 53 if (!localClip.intersects(ambientShadowBounds)) { 54#if DEBUG_SHADOW 55 ALOGD("Ambient shadow is out of clip rect!"); 56#endif 57 return; 58 } 59 60 AmbientShadow::createAmbientShadow(isCasterOpaque, casterPolygon, 61 casterVertexCount, centroid3d, heightFactor, geomFactor, 62 shadowVertexBuffer); 63} 64 65void ShadowTessellator::tessellateSpotShadow(bool isCasterOpaque, 66 const Vector3* casterPolygon, int casterVertexCount, const Vector3& casterCentroid, 67 const mat4& receiverTransform, const Vector3& lightCenter, int lightRadius, 68 const Rect& casterBounds, const Rect& localClip, VertexBuffer& shadowVertexBuffer) { 69 ATRACE_CALL(); 70 71 Vector3 adjustedLightCenter(lightCenter); 72 if (CC_UNLIKELY(Properties::overrideLightPosY > 0)) { 73 adjustedLightCenter.y = - Properties::overrideLightPosY; // negated since this shifts up 74 } 75 if (CC_UNLIKELY(Properties::overrideLightPosZ > 0)) { 76 adjustedLightCenter.z = Properties::overrideLightPosZ; 77 } 78 79#if DEBUG_SHADOW 80 ALOGD("light center %f %f %f %d", 81 adjustedLightCenter.x, adjustedLightCenter.y, adjustedLightCenter.z, lightRadius); 82#endif 83 if (isnan(adjustedLightCenter.x) 84 || isnan(adjustedLightCenter.y) 85 || isnan(adjustedLightCenter.z)) { 86 return; 87 } 88 89 // light position (because it's in local space) needs to compensate for receiver transform 90 // TODO: should apply to light orientation, not just position 91 Matrix4 reverseReceiverTransform; 92 reverseReceiverTransform.loadInverse(receiverTransform); 93 reverseReceiverTransform.mapPoint3d(adjustedLightCenter); 94 95 if (CC_UNLIKELY(Properties::overrideLightRadius > 0)) { 96 lightRadius = Properties::overrideLightRadius; 97 } 98 99 // Now light and caster are both in local space, we will check whether 100 // the shadow is within the clip area. 101 Rect lightRect = Rect(adjustedLightCenter.x - lightRadius, adjustedLightCenter.y - lightRadius, 102 adjustedLightCenter.x + lightRadius, adjustedLightCenter.y + lightRadius); 103 lightRect.unionWith(localClip); 104 if (!lightRect.intersects(casterBounds)) { 105#if DEBUG_SHADOW 106 ALOGD("Spot shadow is out of clip rect!"); 107#endif 108 return; 109 } 110 111 SpotShadow::createSpotShadow(isCasterOpaque, adjustedLightCenter, lightRadius, 112 casterPolygon, casterVertexCount, casterCentroid, shadowVertexBuffer); 113 114#if DEBUG_SHADOW 115 if(shadowVertexBuffer.getVertexCount() <= 0) { 116 ALOGD("Spot shadow generation failed %d", shadowVertexBuffer.getVertexCount()); 117 } 118#endif 119} 120 121/** 122 * Calculate the centroid of a 2d polygon. 123 * 124 * @param poly The polygon, which is represented in a Vector2 array. 125 * @param polyLength The length of the polygon in terms of number of vertices. 126 * @return the centroid of the polygon. 127 */ 128Vector2 ShadowTessellator::centroid2d(const Vector2* poly, int polyLength) { 129 double sumx = 0; 130 double sumy = 0; 131 int p1 = polyLength - 1; 132 double area = 0; 133 for (int p2 = 0; p2 < polyLength; p2++) { 134 double x1 = poly[p1].x; 135 double y1 = poly[p1].y; 136 double x2 = poly[p2].x; 137 double y2 = poly[p2].y; 138 double a = (x1 * y2 - x2 * y1); 139 sumx += (x1 + x2) * a; 140 sumy += (y1 + y2) * a; 141 area += a; 142 p1 = p2; 143 } 144 145 Vector2 centroid = poly[0]; 146 if (area != 0) { 147 centroid = (Vector2){static_cast<float>(sumx / (3 * area)), 148 static_cast<float>(sumy / (3 * area))}; 149 } else { 150 ALOGW("Area is 0 while computing centroid!"); 151 } 152 return centroid; 153} 154 155// Make sure p1 -> p2 is going CW around the poly. 156Vector2 ShadowTessellator::calculateNormal(const Vector2& p1, const Vector2& p2) { 157 Vector2 result = p2 - p1; 158 if (result.x != 0 || result.y != 0) { 159 result.normalize(); 160 // Calculate the normal , which is CCW 90 rotate to the delta. 161 float tempy = result.y; 162 result.y = result.x; 163 result.x = -tempy; 164 } 165 return result; 166} 167 168int ShadowTessellator::getExtraVertexNumber(const Vector2& vector1, 169 const Vector2& vector2, float divisor) { 170 // When there is no distance difference, there is no need for extra vertices. 171 if (vector1.lengthSquared() == 0 || vector2.lengthSquared() == 0) { 172 return 0; 173 } 174 // The formula is : 175 // extraNumber = floor(acos(dot(n1, n2)) / (M_PI / EXTRA_VERTEX_PER_PI)) 176 // The value ranges for each step are: 177 // dot( ) --- [-1, 1] 178 // acos( ) --- [0, M_PI] 179 // floor(...) --- [0, EXTRA_VERTEX_PER_PI] 180 float dotProduct = vector1.dot(vector2); 181 // make sure that dotProduct value is in acsof input range [-1, 1] 182 dotProduct = MathUtils::clamp(dotProduct, -1.0f, 1.0f); 183 // TODO: Use look up table for the dotProduct to extraVerticesNumber 184 // computation, if needed. 185 float angle = acosf(dotProduct); 186 return (int) floor(angle / divisor); 187} 188 189void ShadowTessellator::checkOverflow(int used, int total, const char* bufferName) { 190 LOG_ALWAYS_FATAL_IF(used > total, "Error: %s overflow!!! used %d, total %d", 191 bufferName, used, total); 192} 193 194}; // namespace uirenderer 195}; // namespace android 196