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 #include "renderstate/Stencil.h"
18
19 #include "Caches.h"
20 #include "Debug.h"
21 #include "Extensions.h"
22 #include "Properties.h"
23
24 #include <GLES2/gl2ext.h>
25
26 namespace android {
27 namespace uirenderer {
28
29 #if DEBUG_STENCIL
30 #define STENCIL_WRITE_VALUE 0xff
31 #define STENCIL_MASK_VALUE 0xff
32 #else
33 #define STENCIL_WRITE_VALUE 0x1
34 #define STENCIL_MASK_VALUE 0x1
35 #endif
36
getStencilSize()37 uint8_t Stencil::getStencilSize() {
38 return STENCIL_BUFFER_SIZE;
39 }
40
41 /**
42 * This method will return either GL_STENCIL_INDEX4_OES if supported,
43 * GL_STENCIL_INDEX8 if not.
44 *
45 * Layers can't use a single bit stencil because multi-rect ClipArea needs a high enough
46 * stencil resolution to represent the summation of multiple intersecting rect geometries.
47 */
getLayerStencilFormat()48 GLenum Stencil::getLayerStencilFormat() {
49 #if !DEBUG_STENCIL
50 const Extensions& extensions = DeviceInfo::get()->extensions();
51 if (extensions.has4BitStencil()) {
52 return GL_STENCIL_INDEX4_OES;
53 }
54 #endif
55 return GL_STENCIL_INDEX8;
56 }
57
clear()58 void Stencil::clear() {
59 glStencilMask(0xff);
60 glClearStencil(0);
61 glClear(GL_STENCIL_BUFFER_BIT);
62
63 if (mState == StencilState::Test) {
64 // reset to test state, with immutable stencil
65 glStencilMask(0);
66 }
67 }
68
enableTest(int incrementThreshold)69 void Stencil::enableTest(int incrementThreshold) {
70 if (mState != StencilState::Test) {
71 enable();
72 if (incrementThreshold > 0) {
73 glStencilFunc(GL_EQUAL, incrementThreshold, 0xff);
74 } else {
75 glStencilFunc(GL_EQUAL, STENCIL_WRITE_VALUE, STENCIL_MASK_VALUE);
76 }
77 // We only want to test, let's keep everything
78 glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
79 glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
80 glStencilMask(0);
81 mState = StencilState::Test;
82 }
83 }
84
enableWrite(int incrementThreshold)85 void Stencil::enableWrite(int incrementThreshold) {
86 if (mState != StencilState::Write) {
87 enable();
88 if (incrementThreshold > 0) {
89 glStencilFunc(GL_ALWAYS, 1, 0xff);
90 // The test always passes so the first two values are meaningless
91 glStencilOp(GL_INCR, GL_INCR, GL_INCR);
92 } else {
93 glStencilFunc(GL_ALWAYS, STENCIL_WRITE_VALUE, STENCIL_MASK_VALUE);
94 // The test always passes so the first two values are meaningless
95 glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
96 }
97 glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
98 glStencilMask(0xff);
99 mState = StencilState::Write;
100 }
101 }
102
enableDebugTest(GLint value,bool greater)103 void Stencil::enableDebugTest(GLint value, bool greater) {
104 enable();
105 glStencilFunc(greater ? GL_LESS : GL_EQUAL, value, 0xffffffff);
106 // We only want to test, let's keep everything
107 glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
108 mState = StencilState::Test;
109 glStencilMask(0);
110 }
111
enableDebugWrite()112 void Stencil::enableDebugWrite() {
113 enable();
114 glStencilFunc(GL_ALWAYS, 0x1, 0xffffffff);
115 // The test always passes so the first two values are meaningless
116 glStencilOp(GL_KEEP, GL_KEEP, GL_INCR);
117 glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
118 mState = StencilState::Write;
119 glStencilMask(0xff);
120 }
121
enable()122 void Stencil::enable() {
123 if (mState == StencilState::Disabled) {
124 glEnable(GL_STENCIL_TEST);
125 }
126 }
127
disable()128 void Stencil::disable() {
129 if (mState != StencilState::Disabled) {
130 glDisable(GL_STENCIL_TEST);
131 mState = StencilState::Disabled;
132 }
133 }
134
dump()135 void Stencil::dump() {
136 ALOGD("Stencil: state %d", mState);
137 }
138
139 }; // namespace uirenderer
140 }; // namespace android
141