VertexBuffer.h revision c93e45cf045f41aea95f856173e4043d988a5a5c 
1/*
2 * Copyright (C) 2012 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#ifndef ANDROID_HWUI_VERTEX_BUFFER_H
18#define ANDROID_HWUI_VERTEX_BUFFER_H
19
20
21namespace android {
22namespace uirenderer {
23
24class VertexBuffer {
25public:
26    enum Mode {
27        kStandard = 0,
28        kOnePolyRingShadow = 1,
29        kTwoPolyRingShadow = 2
30    };
31
32    VertexBuffer()
33            : mBuffer(0)
34            , mVertexCount(0)
35            , mByteCount(0)
36            , mMode(kStandard)
37            , mCleanupMethod(NULL)
38    {}
39
40    ~VertexBuffer() {
41        if (mCleanupMethod) mCleanupMethod(mBuffer);
42    }
43
44    /**
45       This should be the only method used by the Tessellator. Subsequent calls to
46       alloc will allocate space within the first allocation (useful if you want to
47       eventually allocate multiple regions within a single VertexBuffer, such as
48       with PathTessellator::tessellateLines())
49     */
50    template <class TYPE>
51    TYPE* alloc(int vertexCount) {
52        if (mVertexCount) {
53            TYPE* reallocBuffer = (TYPE*)mReallocBuffer;
54            // already have allocated the buffer, re-allocate space within
55            if (mReallocBuffer != mBuffer) {
56                // not first re-allocation, leave space for degenerate triangles to separate strips
57                reallocBuffer += 2;
58            }
59            mReallocBuffer = reallocBuffer + vertexCount;
60            return reallocBuffer;
61        }
62        mVertexCount = vertexCount;
63        mByteCount = mVertexCount * sizeof(TYPE);
64        mReallocBuffer = mBuffer = (void*)new TYPE[vertexCount];
65        memset(mBuffer, 0, sizeof(TYPE) * vertexCount);
66
67        mCleanupMethod = &(cleanup<TYPE>);
68
69        return (TYPE*)mBuffer;
70    }
71
72    template <class TYPE>
73    void copyInto(const VertexBuffer& srcBuffer, float xOffset, float yOffset) {
74        int verticesToCopy = srcBuffer.getVertexCount();
75
76        TYPE* dst = alloc<TYPE>(verticesToCopy);
77        TYPE* src = (TYPE*)srcBuffer.getBuffer();
78
79        for (int i = 0; i < verticesToCopy; i++) {
80            TYPE::copyWithOffset(&dst[i], src[i], xOffset, yOffset);
81        }
82    }
83
84    /**
85     * Brute force bounds computation, used only if the producer of this
86     * vertex buffer can't determine bounds more simply/efficiently
87     */
88    template <class TYPE>
89    void computeBounds() {
90        if (!mVertexCount) {
91            mBounds.setEmpty();
92            return;
93        }
94        TYPE* current = (TYPE*)mBuffer;
95        TYPE* end = current + mVertexCount;
96        mBounds.set(current->x, current->y, current->x, current->y);
97        for (; current < end; current++) {
98            mBounds.expandToCoverVertex(current->x, current->y);
99        }
100    }
101
102    const void* getBuffer() const { return mBuffer; }
103    const Rect& getBounds() const { return mBounds; }
104    unsigned int getVertexCount() const { return mVertexCount; }
105    unsigned int getSize() const { return mByteCount; }
106    Mode getMode() const { return mMode; }
107
108    void setBounds(Rect bounds) { mBounds = bounds; }
109    void setMode(Mode mode) { mMode = mode; }
110
111    template <class TYPE>
112    void createDegenerateSeparators(int allocSize) {
113        TYPE* end = (TYPE*)mBuffer + mVertexCount;
114        for (TYPE* degen = (TYPE*)mBuffer + allocSize; degen < end; degen += 2 + allocSize) {
115            memcpy(degen, degen - 1, sizeof(TYPE));
116            memcpy(degen + 1, degen + 2, sizeof(TYPE));
117        }
118    }
119
120private:
121    template <class TYPE>
122    static void cleanup(void* buffer) {
123        delete[] (TYPE*)buffer;
124    }
125
126    Rect mBounds;
127    void* mBuffer;
128    unsigned int mVertexCount;
129    unsigned int mByteCount;
130    Mode mMode;
131
132    void* mReallocBuffer; // used for multi-allocation
133
134    void (*mCleanupMethod)(void*);
135};
136
137}; // namespace uirenderer
138}; // namespace android
139
140#endif // ANDROID_HWUI_VERTEX_BUFFER_H
141