AmbientShadow.h revision 63d41abb40b3ce40d8b9bccb1cf186e8158a3687 
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_AMBIENT_SHADOW_H
19#define ANDROID_HWUI_AMBIENT_SHADOW_H
20
21#include "Debug.h"
22#include "Vector.h"
23#include "VertexBuffer.h"
24
25namespace android {
26namespace uirenderer {
27
28/**
29 * AmbientShadow is used to calculate the ambient shadow value around a polygon.
30 *
31 * TODO: calculateIntersection() now is O(N*M), where N is the number of
32 * polygon's vertics and M is the number of rays. In fact, by staring tracing
33 * the vertex from the previous intersection, the algorithm can be O(N + M);
34 */
35class AmbientShadow {
36public:
37    static void createAmbientShadow(const Vector3* poly, int polyLength,
38            const Vector3& centroid3d, float heightFactor, float geomFactor,
39            VertexBuffer& shadowVertexBuffer);
40
41private:
42    static void calculateRayDirections(int rays, Vector2* dir);
43
44    static void calculateIntersection(const Vector3* poly, int nbVertices,
45            const Vector3& start, const Vector2& dir, int& outEdgeIndex,
46            float& outEdgeFraction, float& outRayDist);
47
48    static void calculateNormal(int rays, int currentRayIndex, const Vector2* dir,
49            const float* rayDist, Vector2& normal);
50}; // AmbientShadow
51
52}; // namespace uirenderer
53}; // namespace android
54
55#endif // ANDROID_HWUI_AMBIENT_SHADOW_H
56