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 26namespace android { 27namespace uirenderer { 28 29class 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 69class ShadowTessellator { 70public: 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