1 2 /* 3 * Copyright (C) 2013 The Android Open Source Project 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 #ifndef ANDROID_HWUI_SHADOW_TESSELLATOR_H 19 #define ANDROID_HWUI_SHADOW_TESSELLATOR_H 20 21 #include <SkPath.h> 22 23 #include "Debug.h" 24 #include "Matrix.h" 25 26 namespace android { 27 namespace uirenderer { 28 29 class VertexBuffer; 30 31 // All SHADOW_* are used to define all the geometry property of shadows. 32 // Use a simplified example to illustrate the geometry setup here. 33 // Assuming we use 6 rays and only 1 layer, Then we will have 2 hexagons, which 34 // are 0 to 5 and 6 to 11. The area between them will be the penumbra area, and 35 // the area inside the 2nd hexagon is the umbra. 36 // Ambient shadow is using only 1 layer for opaque caster, otherwise, spot 37 // shadow and ambient shadow are using 2 layers. 38 // Triange strip indices for penumbra area: (0, 6, 1, 7, 2, 8, 3, 9, 4, 10, 5, 11, 0, 6) 39 // 0 40 // 41 // 5 6 1 42 // 11 7 43 // 44 // 10 8 45 // 4 9 2 46 // 47 // 3 48 49 // The total number of rays starting from the centroid of shadow area, in order 50 // to generate the shadow geometry. 51 #define SHADOW_RAY_COUNT 128 52 53 // The total number of all the vertices representing the shadow. 54 // For the case we only have 1 layer, then we will just fill only 2/3 of it. 55 #define SHADOW_VERTEX_COUNT (3 * SHADOW_RAY_COUNT) 56 57 // The total number of indices used for drawing the shadow geometry as triangle strips. 58 // Depending on the mode we are drawing, we can have 1 layer or 2 layers. 59 // Therefore, we only build the longer index buffer. 60 #define TWO_POLY_RING_SHADOW_INDEX_COUNT (4 * (SHADOW_RAY_COUNT + 1)) 61 #define ONE_POLY_RING_SHADOW_INDEX_COUNT (2 * (SHADOW_RAY_COUNT + 1)) 62 63 #define MAX_SHADOW_INDEX_COUNT TWO_POLY_RING_SHADOW_INDEX_COUNT 64 65 #define SHADOW_MIN_CASTER_Z 0.001f 66 67 #define MINIMAL_DELTA_THETA (M_PI / 180 / 1000) 68 69 class ShadowTessellator { 70 public: 71 static void tessellateAmbientShadow(bool isCasterOpaque, const Vector3* casterPolygon, 72 int casterVertexCount, const Vector3& centroid3d, 73 const Rect& casterBounds, const Rect& localClip, float maxZ, 74 VertexBuffer& shadowVertexBuffer); 75 76 static void tessellateSpotShadow(bool isCasterOpaque, const Vector3* casterPolygon, 77 int casterVertexCount, const Vector3& casterCentroid, 78 const mat4& receiverTransform, const Vector3& lightCenter, 79 int lightRadius, const Rect& casterBounds, 80 const Rect& localClip, VertexBuffer& shadowVertexBuffer); 81 82 static Vector2 centroid2d(const Vector2* poly, int polyLength); 83 84 static Vector2 calculateNormal(const Vector2& p1, const Vector2& p2); 85 86 static int getExtraVertexNumber(const Vector2& vector1, const Vector2& vector2, float divisor); 87 88 static void checkOverflow(int used, int total, const char* bufferName); 89 }; // ShadowTessellator 90 91 }; // namespace uirenderer 92 }; // namespace android 93 94 #endif // ANDROID_HWUI_SHADOW_TESSELLATOR_H 95
