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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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