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
Stencil()37 Stencil::Stencil()
38 : mState(kDisabled) {
39 }
40
getStencilSize()41 uint8_t Stencil::getStencilSize() {
42 return STENCIL_BUFFER_SIZE;
43 }
44
45 /**
46 * This method will return either GL_STENCIL_INDEX4_OES if supported,
47 * GL_STENCIL_INDEX8 if not.
48 *
49 * Layers can't use a single bit stencil because multi-rect ClipArea needs a high enough
50 * stencil resolution to represent the summation of multiple intersecting rect geometries.
51 */
getLayerStencilFormat()52 GLenum Stencil::getLayerStencilFormat() {
53 #if !DEBUG_STENCIL
54 const Extensions& extensions = Caches::getInstance().extensions();
55 if (extensions.has4BitStencil()) {
56 return GL_STENCIL_INDEX4_OES;
57 }
58 #endif
59 return GL_STENCIL_INDEX8;
60 }
61
clear()62 void Stencil::clear() {
63 glStencilMask(0xff);
64 glClearStencil(0);
65 glClear(GL_STENCIL_BUFFER_BIT);
66
67 if (mState == kTest) {
68 // reset to test state, with immutable stencil
69 glStencilMask(0);
70 }
71 }
72
enableTest(int incrementThreshold)73 void Stencil::enableTest(int incrementThreshold) {
74 if (mState != kTest) {
75 enable();
76 if (incrementThreshold > 0) {
77 glStencilFunc(GL_EQUAL, incrementThreshold, 0xff);
78 } else {
79 glStencilFunc(GL_EQUAL, STENCIL_WRITE_VALUE, STENCIL_MASK_VALUE);
80 }
81 // We only want to test, let's keep everything
82 glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
83 glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
84 glStencilMask(0);
85 mState = kTest;
86 }
87 }
88
enableWrite(int incrementThreshold)89 void Stencil::enableWrite(int incrementThreshold) {
90 if (mState != kWrite) {
91 enable();
92 if (incrementThreshold > 0) {
93 glStencilFunc(GL_ALWAYS, 1, 0xff);
94 // The test always passes so the first two values are meaningless
95 glStencilOp(GL_INCR, GL_INCR, GL_INCR);
96 } else {
97 glStencilFunc(GL_ALWAYS, STENCIL_WRITE_VALUE, STENCIL_MASK_VALUE);
98 // The test always passes so the first two values are meaningless
99 glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
100 }
101 glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
102 glStencilMask(0xff);
103 mState = kWrite;
104 }
105 }
106
enableDebugTest(GLint value,bool greater)107 void Stencil::enableDebugTest(GLint value, bool greater) {
108 enable();
109 glStencilFunc(greater ? GL_LESS : GL_EQUAL, value, 0xffffffff);
110 // We only want to test, let's keep everything
111 glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
112 mState = kTest;
113 glStencilMask(0);
114 }
115
enableDebugWrite()116 void Stencil::enableDebugWrite() {
117 enable();
118 glStencilFunc(GL_ALWAYS, 0x1, 0xffffffff);
119 // The test always passes so the first two values are meaningless
120 glStencilOp(GL_KEEP, GL_KEEP, GL_INCR);
121 glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
122 mState = kWrite;
123 glStencilMask(0xff);
124 }
125
enable()126 void Stencil::enable() {
127 if (mState == kDisabled) {
128 glEnable(GL_STENCIL_TEST);
129 }
130 }
131
disable()132 void Stencil::disable() {
133 if (mState != kDisabled) {
134 glDisable(GL_STENCIL_TEST);
135 mState = kDisabled;
136 }
137 }
138
dump()139 void Stencil::dump() {
140 ALOGD("Stencil: state %d", mState);
141 }
142
143 }; // namespace uirenderer
144 }; // namespace android
145