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1 /* | |
2 * Copyright 2016 The WebRTC project authors. All Rights Reserved. | |
3 * | |
4 * Use of this source code is governed by a BSD-style license | |
5 * that can be found in the LICENSE file in the root of the source | |
6 * tree. An additional intellectual property rights grant can be found | |
7 * in the file PATENTS. All contributing project authors may | |
8 * be found in the AUTHORS file in the root of the source tree. | |
9 */ | |
10 | |
11 #import "RTCShader.h" | |
12 | |
13 #import "RTCI420TextureCache.h" | |
14 #import "RTCShader+Private.h" | |
15 #import "WebRTC/RTCLogging.h" | |
16 #import "WebRTC/RTCVideoFrame.h" | |
17 | |
18 #include "webrtc/base/optional.h" | |
19 | |
20 // Fragment shader converts YUV values from input textures into a final RGB | |
21 // pixel. The conversion formula is from http://www.fourcc.org/fccyvrgb.php. | |
22 static const char kI420FragmentShaderSource[] = | |
23 SHADER_VERSION | |
24 "precision highp float;" | |
25 FRAGMENT_SHADER_IN " vec2 v_texcoord;\n" | |
26 "uniform lowp sampler2D s_textureY;\n" | |
27 "uniform lowp sampler2D s_textureU;\n" | |
28 "uniform lowp sampler2D s_textureV;\n" | |
29 FRAGMENT_SHADER_OUT | |
30 "void main() {\n" | |
31 " float y, u, v, r, g, b;\n" | |
32 " y = " FRAGMENT_SHADER_TEXTURE "(s_textureY, v_texcoord).r;\n" | |
33 " u = " FRAGMENT_SHADER_TEXTURE "(s_textureU, v_texcoord).r;\n" | |
34 " v = " FRAGMENT_SHADER_TEXTURE "(s_textureV, v_texcoord).r;\n" | |
35 " u = u - 0.5;\n" | |
36 " v = v - 0.5;\n" | |
37 " r = y + 1.403 * v;\n" | |
38 " g = y - 0.344 * u - 0.714 * v;\n" | |
39 " b = y + 1.770 * u;\n" | |
40 " " FRAGMENT_SHADER_COLOR " = vec4(r, g, b, 1.0);\n" | |
41 " }\n"; | |
42 | |
43 @implementation RTCI420Shader { | |
44 RTCI420TextureCache* textureCache; | |
45 // Handles for OpenGL constructs. | |
46 GLuint _i420Program; | |
47 GLuint _vertexArray; | |
48 GLuint _vertexBuffer; | |
49 GLint _ySampler; | |
50 GLint _uSampler; | |
51 GLint _vSampler; | |
52 // Store current rotation and only upload new vertex data when rotation | |
53 // changes. | |
54 rtc::Optional<RTCVideoRotation> _currentRotation; | |
55 } | |
56 | |
57 - (instancetype)initWithContext:(GlContextType *)context { | |
58 if (self = [super init]) { | |
59 textureCache = [[RTCI420TextureCache alloc] initWithContext:context]; | |
60 glPixelStorei(GL_UNPACK_ALIGNMENT, 1); | |
61 if (![self setupI420Program] || | |
62 !RTCSetupVerticesForProgram(_i420Program, &_vertexBuffer, &_vertexArray)
) { | |
63 RTCLog(@"Failed to initialize RTCI420Shader."); | |
64 self = nil; | |
65 } | |
66 } | |
67 return self; | |
68 } | |
69 | |
70 - (void)dealloc { | |
71 glDeleteProgram(_i420Program); | |
72 glDeleteBuffers(1, &_vertexBuffer); | |
73 glDeleteVertexArrays(1, &_vertexArray); | |
74 } | |
75 | |
76 - (BOOL)setupI420Program { | |
77 _i420Program = RTCCreateProgramFromFragmentSource(kI420FragmentShaderSource); | |
78 if (!_i420Program) { | |
79 return NO; | |
80 } | |
81 _ySampler = glGetUniformLocation(_i420Program, "s_textureY"); | |
82 _uSampler = glGetUniformLocation(_i420Program, "s_textureU"); | |
83 _vSampler = glGetUniformLocation(_i420Program, "s_textureV"); | |
84 | |
85 return (_ySampler >= 0 && _uSampler >= 0 && _vSampler >= 0); | |
86 } | |
87 | |
88 - (BOOL)drawFrame:(RTCVideoFrame*)frame { | |
89 glUseProgram(_i420Program); | |
90 | |
91 [textureCache uploadFrameToTextures:frame]; | |
92 | |
93 #if !TARGET_OS_IPHONE | |
94 glBindVertexArray(_vertexArray); | |
95 #endif | |
96 | |
97 glActiveTexture(GL_TEXTURE0); | |
98 glBindTexture(GL_TEXTURE_2D, textureCache.yTexture); | |
99 glUniform1i(_ySampler, 0); | |
100 | |
101 glActiveTexture(GL_TEXTURE1); | |
102 glBindTexture(GL_TEXTURE_2D, textureCache.uTexture); | |
103 glUniform1i(_uSampler, 1); | |
104 | |
105 glActiveTexture(GL_TEXTURE2); | |
106 glBindTexture(GL_TEXTURE_2D, textureCache.vTexture); | |
107 glUniform1i(_vSampler, 2); | |
108 | |
109 glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer); | |
110 if (!_currentRotation || frame.rotation != *_currentRotation) { | |
111 _currentRotation = rtc::Optional<RTCVideoRotation>(frame.rotation); | |
112 RTCSetVertexData(*_currentRotation); | |
113 } | |
114 glDrawArrays(GL_TRIANGLE_FAN, 0, 4); | |
115 | |
116 return YES; | |
117 } | |
118 | |
119 @end | |
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