iOS render: Handle frame rotation in OpenGL

webrtc/sdk/objc/Framework/Classes/RTCNativeNV12Shader.mm

 /*
  *  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"
 
 // Native CVPixelBufferRef rendering is only supported on iPhone because it
 // depends on CVOpenGLESTextureCacheCreate.
 #if TARGET_OS_IPHONE
 
 #import <CoreVideo/CVOpenGLESTextureCache.h>
 
 #import "RTCShader+Private.h"
 #import "WebRTC/RTCVideoFrame.h"
 
 #include "webrtc/base/checks.h"
+#include "webrtc/base/optional.h"
+#include "webrtc/common_video/rotation.h"
 
 static const char kNV12FragmentShaderSource[] =
   SHADER_VERSION
   "precision mediump float;"
   FRAGMENT_SHADER_IN " vec2 v_texcoord;\n"
   "uniform lowp sampler2D s_textureY;\n"
   "uniform lowp sampler2D s_textureUV;\n"
   FRAGMENT_SHADER_OUT
   "void main() {\n"
   "    mediump float y;\n"
   "    mediump vec2 uv;\n"
   "    y = " FRAGMENT_SHADER_TEXTURE "(s_textureY, v_texcoord).r;\n"
   "    uv = " FRAGMENT_SHADER_TEXTURE "(s_textureUV, v_texcoord).ra -\n"
   "        vec2(0.5, 0.5);\n"
   "    " FRAGMENT_SHADER_COLOR " = vec4(y + 1.403 * uv.y,\n"
   "                                     y - 0.344 * uv.x - 0.714 * uv.y,\n"
   "                                     y + 1.770 * uv.x,\n"
   "                                     1.0);\n"
   "  }\n";
 
 @implementation RTCNativeNV12Shader {
   GLuint _vertexBuffer;
   GLuint _nv12Program;
   GLint _ySampler;
   GLint _uvSampler;
   CVOpenGLESTextureCacheRef _textureCache;
+  // Store current rotation and only upload new vertex data when rotation
+  // changes.
+  rtc::Optional<webrtc::VideoRotation> _currentRotation;
 }
 
 - (instancetype)initWithContext:(GlContextType *)context {
   if (self = [super init]) {
     if (![self setupNV12Program] || ![self setupTextureCacheWithContext:context] ||
         !RTCSetupVerticesForProgram(_nv12Program, &_vertexBuffer, nullptr)) {
       self = nil;
     }
   }
   return self;
@@ skipping 83 matching lines @@
 
   RTC_CHECK_EQ(static_cast<GLenum>(GL_TEXTURE_2D),
                CVOpenGLESTextureGetTarget(chromaTexture));
   glBindTexture(GL_TEXTURE_2D, CVOpenGLESTextureGetName(chromaTexture));
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 
   glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
+  if (!_currentRotation || frame.rotation != *_currentRotation) {
+    _currentRotation = rtc::Optional<webrtc::VideoRotation>(
+        static_cast<webrtc::VideoRotation>(frame.rotation));
+    RTCSetVertexData(*_currentRotation);
+  }
   glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 
   CFRelease(chromaTexture);
   CFRelease(lumaTexture);
 
   return YES;
 }
 
 @end
 #endif  // TARGET_OS_IPHONE