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 #include <math.h>
18 #include <utils/Log.h>
19 #include <utils/Trace.h>
20 #include <utils/MathUtils.h>
21
22 #include "AmbientShadow.h"
23 #include "Properties.h"
24 #include "ShadowTessellator.h"
25 #include "SpotShadow.h"
26 #include "Vector.h"
27
28 namespace android {
29 namespace uirenderer {
30
tessellateAmbientShadow(bool isCasterOpaque,const Vector3 * casterPolygon,int casterVertexCount,const Vector3 & centroid3d,const Rect & casterBounds,const Rect & localClip,float maxZ,VertexBuffer & shadowVertexBuffer)31 void ShadowTessellator::tessellateAmbientShadow(bool isCasterOpaque,
32 const Vector3* casterPolygon, int casterVertexCount,
33 const Vector3& centroid3d, const Rect& casterBounds,
34 const Rect& localClip, float maxZ, VertexBuffer& shadowVertexBuffer) {
35 ATRACE_CALL();
36
37 // A bunch of parameters to tweak the shadow.
38 // TODO: Allow some of these changable by debug settings or APIs.
39 float heightFactor = 1.0f / 128;
40 const float geomFactor = 64;
41
42 if (CC_UNLIKELY(Properties::overrideAmbientRatio > 0.0f)) {
43 heightFactor *= Properties::overrideAmbientRatio;
44 }
45
46 Rect ambientShadowBounds(casterBounds);
47 ambientShadowBounds.outset(maxZ * geomFactor * heightFactor);
48
49 if (!localClip.intersects(ambientShadowBounds)) {
50 #if DEBUG_SHADOW
51 ALOGD("Ambient shadow is out of clip rect!");
52 #endif
53 return;
54 }
55
56 AmbientShadow::createAmbientShadow(isCasterOpaque, casterPolygon,
57 casterVertexCount, centroid3d, heightFactor, geomFactor,
58 shadowVertexBuffer);
59 }
60
tessellateSpotShadow(bool isCasterOpaque,const Vector3 * casterPolygon,int casterVertexCount,const Vector3 & casterCentroid,const mat4 & receiverTransform,const Vector3 & lightCenter,int lightRadius,const Rect & casterBounds,const Rect & localClip,VertexBuffer & shadowVertexBuffer)61 void ShadowTessellator::tessellateSpotShadow(bool isCasterOpaque,
62 const Vector3* casterPolygon, int casterVertexCount, const Vector3& casterCentroid,
63 const mat4& receiverTransform, const Vector3& lightCenter, int lightRadius,
64 const Rect& casterBounds, const Rect& localClip, VertexBuffer& shadowVertexBuffer) {
65 ATRACE_CALL();
66
67 Vector3 adjustedLightCenter(lightCenter);
68 if (CC_UNLIKELY(Properties::overrideLightPosY > 0)) {
69 adjustedLightCenter.y = - Properties::overrideLightPosY; // negated since this shifts up
70 }
71 if (CC_UNLIKELY(Properties::overrideLightPosZ > 0)) {
72 adjustedLightCenter.z = Properties::overrideLightPosZ;
73 }
74
75 #if DEBUG_SHADOW
76 ALOGD("light center %f %f %f %d",
77 adjustedLightCenter.x, adjustedLightCenter.y, adjustedLightCenter.z, lightRadius);
78 #endif
79 if (isnan(adjustedLightCenter.x)
80 || isnan(adjustedLightCenter.y)
81 || isnan(adjustedLightCenter.z)) {
82 return;
83 }
84
85 // light position (because it's in local space) needs to compensate for receiver transform
86 // TODO: should apply to light orientation, not just position
87 Matrix4 reverseReceiverTransform;
88 reverseReceiverTransform.loadInverse(receiverTransform);
89 reverseReceiverTransform.mapPoint3d(adjustedLightCenter);
90
91 if (CC_UNLIKELY(Properties::overrideLightRadius > 0)) {
92 lightRadius = Properties::overrideLightRadius;
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
117 /**
118 * Calculate the centroid of a 2d polygon.
119 *
120 * @param poly The polygon, which is represented in a Vector2 array.
121 * @param polyLength The length of the polygon in terms of number of vertices.
122 * @return the centroid of the polygon.
123 */
centroid2d(const Vector2 * poly,int polyLength)124 Vector2 ShadowTessellator::centroid2d(const Vector2* poly, int polyLength) {
125 double sumx = 0;
126 double sumy = 0;
127 int p1 = polyLength - 1;
128 double area = 0;
129 for (int p2 = 0; p2 < polyLength; p2++) {
130 double x1 = poly[p1].x;
131 double y1 = poly[p1].y;
132 double x2 = poly[p2].x;
133 double y2 = poly[p2].y;
134 double a = (x1 * y2 - x2 * y1);
135 sumx += (x1 + x2) * a;
136 sumy += (y1 + y2) * a;
137 area += a;
138 p1 = p2;
139 }
140
141 Vector2 centroid = poly[0];
142 if (area != 0) {
143 centroid = (Vector2){static_cast<float>(sumx / (3 * area)),
144 static_cast<float>(sumy / (3 * area))};
145 } else {
146 ALOGW("Area is 0 while computing centroid!");
147 }
148 return centroid;
149 }
150
151 // Make sure p1 -> p2 is going CW around the poly.
calculateNormal(const Vector2 & p1,const Vector2 & p2)152 Vector2 ShadowTessellator::calculateNormal(const Vector2& p1, const Vector2& p2) {
153 Vector2 result = p2 - p1;
154 if (result.x != 0 || result.y != 0) {
155 result.normalize();
156 // Calculate the normal , which is CCW 90 rotate to the delta.
157 float tempy = result.y;
158 result.y = result.x;
159 result.x = -tempy;
160 }
161 return result;
162 }
163
getExtraVertexNumber(const Vector2 & vector1,const Vector2 & vector2,float divisor)164 int ShadowTessellator::getExtraVertexNumber(const Vector2& vector1,
165 const Vector2& vector2, float divisor) {
166 // When there is no distance difference, there is no need for extra vertices.
167 if (vector1.lengthSquared() == 0 || vector2.lengthSquared() == 0) {
168 return 0;
169 }
170 // The formula is :
171 // extraNumber = floor(acos(dot(n1, n2)) / (M_PI / EXTRA_VERTEX_PER_PI))
172 // The value ranges for each step are:
173 // dot( ) --- [-1, 1]
174 // acos( ) --- [0, M_PI]
175 // floor(...) --- [0, EXTRA_VERTEX_PER_PI]
176 float dotProduct = vector1.dot(vector2);
177 // make sure that dotProduct value is in acsof input range [-1, 1]
178 dotProduct = MathUtils::clamp(dotProduct, -1.0f, 1.0f);
179 // TODO: Use look up table for the dotProduct to extraVerticesNumber
180 // computation, if needed.
181 float angle = acosf(dotProduct);
182 return (int) floor(angle / divisor);
183 }
184
checkOverflow(int used,int total,const char * bufferName)185 void ShadowTessellator::checkOverflow(int used, int total, const char* bufferName) {
186 LOG_ALWAYS_FATAL_IF(used > total, "Error: %s overflow!!! used %d, total %d",
187 bufferName, used, total);
188 }
189
190 }; // namespace uirenderer
191 }; // namespace android
192