Reland of Split iOS sdk in to separate targets

webrtc/sdk/objc/Framework/Classes/Video/RTCShader.mm

Index: webrtc/sdk/objc/Framework/Classes/Video/RTCShader.mm
diff --git a/webrtc/sdk/objc/Framework/Classes/Video/RTCShader.mm b/webrtc/sdk/objc/Framework/Classes/Video/RTCShader.mm
new file mode 100644
index 0000000000000000000000000000000000000000..155a0165a13a2ca8b3ef0eaf7dff3f4abb49de46
--- /dev/null
+++ b/webrtc/sdk/objc/Framework/Classes/Video/RTCShader.mm
@@ -0,0 +1,184 @@
+/*
+ *  Copyright 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#import "RTCShader.h"
+
+#include <algorithm>
+#include <array>
+#include <memory>
+
+#import "RTCShader+Private.h"
+
+#include "webrtc/base/checks.h"
+#include "webrtc/base/logging.h"
+
+// Vertex shader doesn't do anything except pass coordinates through.
+const char kRTCVertexShaderSource[] =
+  SHADER_VERSION
+  VERTEX_SHADER_IN " vec2 position;\n"
+  VERTEX_SHADER_IN " vec2 texcoord;\n"
+  VERTEX_SHADER_OUT " vec2 v_texcoord;\n"
+  "void main() {\n"
+  "    gl_Position = vec4(position.x, position.y, 0.0, 1.0);\n"
+  "    v_texcoord = texcoord;\n"
+  "}\n";
+
+// Compiles a shader of the given |type| with GLSL source |source| and returns
+// the shader handle or 0 on error.
+GLuint RTCCreateShader(GLenum type, const GLchar *source) {
+  GLuint shader = glCreateShader(type);
+  if (!shader) {
+    return 0;
+  }
+  glShaderSource(shader, 1, &source, NULL);
+  glCompileShader(shader);
+  GLint compileStatus = GL_FALSE;
+  glGetShaderiv(shader, GL_COMPILE_STATUS, &compileStatus);
+  if (compileStatus == GL_FALSE) {
+    GLint logLength = 0;
+    // The null termination character is included in the returned log length.
+    glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &logLength);
+    if (logLength > 0) {
+      std::unique_ptr<char[]> compileLog(new char[logLength]);
+      // The returned string is null terminated.
+      glGetShaderInfoLog(shader, logLength, NULL, compileLog.get());
+      LOG(LS_ERROR) << "Shader compile error: " << compileLog.get();
+    }
+    glDeleteShader(shader);
+    shader = 0;
+  }
+  return shader;
+}
+
+// Links a shader program with the given vertex and fragment shaders and
+// returns the program handle or 0 on error.
+GLuint RTCCreateProgram(GLuint vertexShader, GLuint fragmentShader) {
+  if (vertexShader == 0 || fragmentShader == 0) {
+    return 0;
+  }
+  GLuint program = glCreateProgram();
+  if (!program) {
+    return 0;
+  }
+  glAttachShader(program, vertexShader);
+  glAttachShader(program, fragmentShader);
+  glLinkProgram(program);
+  GLint linkStatus = GL_FALSE;
+  glGetProgramiv(program, GL_LINK_STATUS, &linkStatus);
+  if (linkStatus == GL_FALSE) {
+    glDeleteProgram(program);
+    program = 0;
+  }
+  return program;
+}
+
+// Creates and links a shader program with the given fragment shader source and
+// a plain vertex shader. Returns the program handle or 0 on error.
+GLuint RTCCreateProgramFromFragmentSource(const char fragmentShaderSource[]) {
+  GLuint vertexShader = RTCCreateShader(GL_VERTEX_SHADER, kRTCVertexShaderSource);
+  RTC_CHECK(vertexShader) << "failed to create vertex shader";
+  GLuint fragmentShader =
+      RTCCreateShader(GL_FRAGMENT_SHADER, fragmentShaderSource);
+  RTC_CHECK(fragmentShader) << "failed to create fragment shader";
+  GLuint program = RTCCreateProgram(vertexShader, fragmentShader);
+  // Shaders are created only to generate program.
+  if (vertexShader) {
+    glDeleteShader(vertexShader);
+  }
+  if (fragmentShader) {
+    glDeleteShader(fragmentShader);
+  }
+  return program;
+}
+
+// Set vertex shader variables 'position' and 'texcoord' in |program| to use
+// |vertexBuffer| and |vertexArray| to store the vertex data.
+BOOL RTCSetupVerticesForProgram(GLuint program, GLuint* vertexBuffer, GLuint* vertexArray) {
+  GLint position = glGetAttribLocation(program, "position");
+  GLint texcoord = glGetAttribLocation(program, "texcoord");
+  if (position < 0 || texcoord < 0) {
+    return NO;
+  }
+#if !TARGET_OS_IPHONE
+  glGenVertexArrays(1, vertexArray);
+  if (*vertexArray == 0) {
+    return NO;
+  }
+  glBindVertexArray(*vertexArray);
+#endif
+  glGenBuffers(1, vertexBuffer);
+  if (*vertexBuffer == 0) {
+    return NO;
+  }
+  glBindBuffer(GL_ARRAY_BUFFER, *vertexBuffer);
+  glBufferData(GL_ARRAY_BUFFER, 4 * 4 * sizeof(GLfloat), NULL, GL_DYNAMIC_DRAW);
+
+  // Read position attribute with size of 2 and stride of 4 beginning at the
+  // start of the array. The last argument indicates offset of data within the
+  // vertex buffer.
+  glVertexAttribPointer(position, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat),
+                        (void *)0);
+  glEnableVertexAttribArray(position);
+
+  // Read texcoord attribute from |gVertices| with size of 2 and stride of 4
+  // beginning at the first texcoord in the array. The last argument indicates
+  // offset of data within |gVertices| as supplied to the vertex buffer.
+  glVertexAttribPointer(texcoord, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat),
+                        (void *)(2 * sizeof(GLfloat)));
+  glEnableVertexAttribArray(texcoord);
+
+  return YES;
+}
+
+// Set vertex data to the currently bound vertex buffer.
+void RTCSetVertexData(RTCVideoRotation rotation) {
+  // When modelview and projection matrices are identity (default) the world is
+  // contained in the square around origin with unit size 2. Drawing to these
+  // coordinates is equivalent to drawing to the entire screen. The texture is
+  // stretched over that square using texture coordinates (u, v) that range
+  // from (0, 0) to (1, 1) inclusive. Texture coordinates are flipped vertically
+  // here because the incoming frame has origin in upper left hand corner but
+  // OpenGL expects origin in bottom left corner.
+  std::array<std::array<GLfloat, 2>, 4> UVCoords = {{
+      {{0, 1}},  // Lower left.
+      {{1, 1}},  // Lower right.
+      {{1, 0}},  // Upper right.
+      {{0, 0}},  // Upper left.
+  }};
+
+  // Rotate the UV coordinates.
+  int rotation_offset;
+  switch (rotation) {
+    case RTCVideoRotation_0:
+      rotation_offset = 0;
+      break;
+    case RTCVideoRotation_90:
+      rotation_offset = 1;
+      break;
+    case RTCVideoRotation_180:
+      rotation_offset = 2;
+      break;
+    case RTCVideoRotation_270:
+      rotation_offset = 3;
+      break;
+  }
+  std::rotate(UVCoords.begin(), UVCoords.begin() + rotation_offset,
+              UVCoords.end());
+
+  const GLfloat gVertices[] = {
+      // X, Y, U, V.
+      -1, -1, UVCoords[0][0], UVCoords[0][1],
+       1, -1, UVCoords[1][0], UVCoords[1][1],
+       1,  1, UVCoords[2][0], UVCoords[2][1],
+      -1,  1, UVCoords[3][0], UVCoords[3][1],
+  };
+
+  glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(gVertices), gVertices);
+}