ShadowTessellator.cpp revision 55bfb4e728fe1db619af5d2c287f4abe711b3343 
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
19#include <math.h>
20#include <utils/Log.h>
21
22#include "AmbientShadow.h"
23#include "ShadowTessellator.h"
24
25namespace android {
26namespace uirenderer {
27
28// TODO: Support path as the input of the polygon instead of the rect's width
29// and height.
30void ShadowTessellator::tessellateAmbientShadow(float width, float height,
31        const mat4& casterTransform, VertexBuffer& shadowVertexBuffer) {
32
33    Vector3 pivot(width / 2, height / 2, 0.0f);
34    casterTransform.mapPoint3d(pivot);
35
36    // TODO: The zScaleFactor need to be mapped to the screen.
37    float zScaleFactor = 0.5;
38    Rect blockRect(pivot.x - width * zScaleFactor, pivot.y - height * zScaleFactor,
39            pivot.x + width * zScaleFactor, pivot.y + height * zScaleFactor);
40
41    // Generate the caster's polygon from the rect.
42    // TODO: support arbitrary polygon, and the z value need to be computed
43    // according to the transformation for each vertex.
44    const int vertexCount = 4;
45    Vector3 polygon[vertexCount];
46    polygon[0].x = blockRect.left;
47    polygon[0].y = blockRect.top;
48    polygon[0].z = pivot.z;
49    polygon[1].x = blockRect.right;
50    polygon[1].y = blockRect.top;
51    polygon[1].z = pivot.z;
52    polygon[2].x = blockRect.right;
53    polygon[2].y = blockRect.bottom;
54    polygon[2].z = pivot.z;
55    polygon[3].x = blockRect.left;
56    polygon[3].y = blockRect.bottom;
57    polygon[3].z = pivot.z;
58
59    // A bunch of parameters to tweak the shadow.
60    // TODO: Allow some of these changable by debug settings or APIs.
61    const int rays = 120;
62    const int layers = 2;
63    const float strength = 0.5;
64    const float heightFactor = 120;
65    const float geomFactor = 60;
66
67    AmbientShadow::createAmbientShadow(polygon, vertexCount, rays, layers, strength,
68            heightFactor, geomFactor, shadowVertexBuffer);
69
70}
71
72}; // namespace uirenderer
73}; // namespace android
74