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_STENCIL_H
18#define ANDROID_HWUI_STENCIL_H
19
20#ifndef LOG_TAG
21    #define LOG_TAG "OpenGLRenderer"
22#endif
23
24#include <GLES2/gl2.h>
25
26#include <cutils/compiler.h>
27
28namespace android {
29namespace uirenderer {
30
31///////////////////////////////////////////////////////////////////////////////
32// Stencil buffer management
33///////////////////////////////////////////////////////////////////////////////
34
35class ANDROID_API Stencil {
36public:
37    Stencil();
38
39    /**
40     * Returns the desired size for the stencil buffer. If the returned value
41     * is 0, then no stencil buffer is required.
42     */
43    ANDROID_API static uint8_t getStencilSize();
44
45    /**
46     * Returns the smallest stencil format accepted by render buffers.
47     */
48    static GLenum getSmallestStencilFormat();
49
50    /**
51     * Clears the stencil buffer.
52     */
53    void clear();
54
55    /**
56     * Enables stencil test. When the stencil test is enabled the stencil
57     * buffer is not written into.
58     */
59    void enableTest();
60
61    /**
62     * Enables stencil write. When stencil write is enabled, the stencil
63     * test always succeeds and the value 0x1 is written in the stencil
64     * buffer for each fragment.
65     */
66    void enableWrite();
67
68    /**
69     * The test passes only when equal to the specified value.
70     */
71    void enableDebugTest(GLint value, bool greater = false);
72
73    /**
74     * Used for debugging. The stencil test always passes and increments.
75     */
76    void enableDebugWrite();
77
78    /**
79     * Disables stencil test and write.
80     */
81    void disable();
82
83    /**
84     * Indicates whether either test or write is enabled.
85     */
86    bool isEnabled() {
87        return mState != kDisabled;
88    }
89
90    /**
91     * Indicates whether testing only is enabled.
92     */
93    bool isTestEnabled() {
94        return mState == kTest;
95    }
96
97private:
98    void enable();
99
100    enum StencilState {
101        kDisabled,
102        kTest,
103        kWrite
104    };
105
106    StencilState mState;
107
108}; // class Stencil
109
110}; // namespace uirenderer
111}; // namespace android
112
113#endif // ANDROID_HWUI_STENCIL_H
114