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Side by Side Diff: webrtc/sdk/objc/Framework/Classes/RTCShader.mm

Issue 2862543002: Split iOS sdk in to separate targets (Closed)
Patch Set: rebase and minor fixes Created 3 years, 7 months ago
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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 #include <algorithm>
14 #include <array>
15 #include <memory>
16
17 #import "RTCShader+Private.h"
18
19 #include "webrtc/base/checks.h"
20 #include "webrtc/base/logging.h"
21
22 // Vertex shader doesn't do anything except pass coordinates through.
23 const char kRTCVertexShaderSource[] =
24 SHADER_VERSION
25 VERTEX_SHADER_IN " vec2 position;\n"
26 VERTEX_SHADER_IN " vec2 texcoord;\n"
27 VERTEX_SHADER_OUT " vec2 v_texcoord;\n"
28 "void main() {\n"
29 " gl_Position = vec4(position.x, position.y, 0.0, 1.0);\n"
30 " v_texcoord = texcoord;\n"
31 "}\n";
32
33 // Compiles a shader of the given |type| with GLSL source |source| and returns
34 // the shader handle or 0 on error.
35 GLuint RTCCreateShader(GLenum type, const GLchar *source) {
36 GLuint shader = glCreateShader(type);
37 if (!shader) {
38 return 0;
39 }
40 glShaderSource(shader, 1, &source, NULL);
41 glCompileShader(shader);
42 GLint compileStatus = GL_FALSE;
43 glGetShaderiv(shader, GL_COMPILE_STATUS, &compileStatus);
44 if (compileStatus == GL_FALSE) {
45 GLint logLength = 0;
46 // The null termination character is included in the returned log length.
47 glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &logLength);
48 if (logLength > 0) {
49 std::unique_ptr<char[]> compileLog(new char[logLength]);
50 // The returned string is null terminated.
51 glGetShaderInfoLog(shader, logLength, NULL, compileLog.get());
52 LOG(LS_ERROR) << "Shader compile error: " << compileLog.get();
53 }
54 glDeleteShader(shader);
55 shader = 0;
56 }
57 return shader;
58 }
59
60 // Links a shader program with the given vertex and fragment shaders and
61 // returns the program handle or 0 on error.
62 GLuint RTCCreateProgram(GLuint vertexShader, GLuint fragmentShader) {
63 if (vertexShader == 0 || fragmentShader == 0) {
64 return 0;
65 }
66 GLuint program = glCreateProgram();
67 if (!program) {
68 return 0;
69 }
70 glAttachShader(program, vertexShader);
71 glAttachShader(program, fragmentShader);
72 glLinkProgram(program);
73 GLint linkStatus = GL_FALSE;
74 glGetProgramiv(program, GL_LINK_STATUS, &linkStatus);
75 if (linkStatus == GL_FALSE) {
76 glDeleteProgram(program);
77 program = 0;
78 }
79 return program;
80 }
81
82 // Creates and links a shader program with the given fragment shader source and
83 // a plain vertex shader. Returns the program handle or 0 on error.
84 GLuint RTCCreateProgramFromFragmentSource(const char fragmentShaderSource[]) {
85 GLuint vertexShader = RTCCreateShader(GL_VERTEX_SHADER, kRTCVertexShaderSource );
86 RTC_CHECK(vertexShader) << "failed to create vertex shader";
87 GLuint fragmentShader =
88 RTCCreateShader(GL_FRAGMENT_SHADER, fragmentShaderSource);
89 RTC_CHECK(fragmentShader) << "failed to create fragment shader";
90 GLuint program = RTCCreateProgram(vertexShader, fragmentShader);
91 // Shaders are created only to generate program.
92 if (vertexShader) {
93 glDeleteShader(vertexShader);
94 }
95 if (fragmentShader) {
96 glDeleteShader(fragmentShader);
97 }
98 return program;
99 }
100
101 // Set vertex shader variables 'position' and 'texcoord' in |program| to use
102 // |vertexBuffer| and |vertexArray| to store the vertex data.
103 BOOL RTCSetupVerticesForProgram(GLuint program, GLuint* vertexBuffer, GLuint* ve rtexArray) {
104 GLint position = glGetAttribLocation(program, "position");
105 GLint texcoord = glGetAttribLocation(program, "texcoord");
106 if (position < 0 || texcoord < 0) {
107 return NO;
108 }
109 #if !TARGET_OS_IPHONE
110 glGenVertexArrays(1, vertexArray);
111 if (*vertexArray == 0) {
112 return NO;
113 }
114 glBindVertexArray(*vertexArray);
115 #endif
116 glGenBuffers(1, vertexBuffer);
117 if (*vertexBuffer == 0) {
118 return NO;
119 }
120 glBindBuffer(GL_ARRAY_BUFFER, *vertexBuffer);
121 glBufferData(GL_ARRAY_BUFFER, 4 * 4 * sizeof(GLfloat), NULL, GL_DYNAMIC_DRAW);
122
123 // Read position attribute with size of 2 and stride of 4 beginning at the
124 // start of the array. The last argument indicates offset of data within the
125 // vertex buffer.
126 glVertexAttribPointer(position, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat),
127 (void *)0);
128 glEnableVertexAttribArray(position);
129
130 // Read texcoord attribute from |gVertices| with size of 2 and stride of 4
131 // beginning at the first texcoord in the array. The last argument indicates
132 // offset of data within |gVertices| as supplied to the vertex buffer.
133 glVertexAttribPointer(texcoord, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat),
134 (void *)(2 * sizeof(GLfloat)));
135 glEnableVertexAttribArray(texcoord);
136
137 return YES;
138 }
139
140 // Set vertex data to the currently bound vertex buffer.
141 void RTCSetVertexData(RTCVideoRotation rotation) {
142 // When modelview and projection matrices are identity (default) the world is
143 // contained in the square around origin with unit size 2. Drawing to these
144 // coordinates is equivalent to drawing to the entire screen. The texture is
145 // stretched over that square using texture coordinates (u, v) that range
146 // from (0, 0) to (1, 1) inclusive. Texture coordinates are flipped vertically
147 // here because the incoming frame has origin in upper left hand corner but
148 // OpenGL expects origin in bottom left corner.
149 std::array<std::array<GLfloat, 2>, 4> UVCoords = {{
150 {{0, 1}}, // Lower left.
151 {{1, 1}}, // Lower right.
152 {{1, 0}}, // Upper right.
153 {{0, 0}}, // Upper left.
154 }};
155
156 // Rotate the UV coordinates.
157 int rotation_offset;
158 switch (rotation) {
159 case RTCVideoRotation_0:
160 rotation_offset = 0;
161 break;
162 case RTCVideoRotation_90:
163 rotation_offset = 1;
164 break;
165 case RTCVideoRotation_180:
166 rotation_offset = 2;
167 break;
168 case RTCVideoRotation_270:
169 rotation_offset = 3;
170 break;
171 }
172 std::rotate(UVCoords.begin(), UVCoords.begin() + rotation_offset,
173 UVCoords.end());
174
175 const GLfloat gVertices[] = {
176 // X, Y, U, V.
177 -1, -1, UVCoords[0][0], UVCoords[0][1],
178 1, -1, UVCoords[1][0], UVCoords[1][1],
179 1, 1, UVCoords[2][0], UVCoords[2][1],
180 -1, 1, UVCoords[3][0], UVCoords[3][1],
181 };
182
183 glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(gVertices), gVertices);
184 }
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