iOS render: Handle frame rotation in OpenGL

webrtc/sdk/objc/Framework/Classes/RTCI420Shader.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"
 
 #include <vector>
 
 #import "RTCShader+Private.h"
 #import "WebRTC/RTCVideoFrame.h"
 
+#include "webrtc/base/optional.h"
+#include "webrtc/common_video/rotation.h"
+
 // |kNumTextures| must not exceed 8, which is the limit in OpenGLES2. Two sets
 // of 3 textures are used here, one for each of the Y, U and V planes. Having
 // two sets alleviates CPU blockage in the event that the GPU is asked to render
 // to a texture that is already in use.
 static const GLsizei kNumTextureSets = 2;
 static const GLsizei kNumTexturesPerSet = 3;
 static const GLsizei kNumTextures = kNumTexturesPerSet * kNumTextureSets;
 
 // Fragment shader converts YUV values from input textures into a final RGB
 // pixel. The conversion formula is from http://www.fourcc.org/fccyvrgb.php.
@@ skipping 22 matching lines @@
   BOOL _hasUnpackRowLength;
   GLint _currentTextureSet;
   // Handles for OpenGL constructs.
   GLuint _textures[kNumTextures];
   GLuint _i420Program;
   GLuint _vertexArray;
   GLuint _vertexBuffer;
   GLint _ySampler;
   GLint _uSampler;
   GLint _vSampler;
+  // Store current rotation and only upload new vertex data when rotation
+  // changes.
+  rtc::Optional<webrtc::VideoRotation> _currentRotation;
   // Used to create a non-padded plane for GPU upload when we receive padded
   // frames.
   std::vector<uint8_t> _planeBuffer;
 }
 
 - (instancetype)initWithContext:(GlContextType *)context {
   if (self = [super init]) {
 #if TARGET_OS_IPHONE
     _hasUnpackRowLength = (context.API == kEAGLRenderingAPIOpenGLES3);
 #else
@@ skipping 42 matching lines @@
 
 - (BOOL)drawFrame:(RTCVideoFrame*)frame {
   glUseProgram(_i420Program);
   if (![self updateTextureDataForFrame:frame]) {
     return NO;
   }
 #if !TARGET_OS_IPHONE
   glBindVertexArray(_vertexArray);
 #endif
   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);
 
   return YES;
 }
 
 - (void)uploadPlane:(const uint8_t *)plane
             sampler:(GLint)sampler
              offset:(GLint)offset
               width:(size_t)width
              height:(size_t)height
@@ skipping 70 matching lines @@
              offset:textureOffset + 2
               width:frame.chromaWidth
              height:frame.chromaHeight
              stride:frame.vPitch];
 
   _currentTextureSet = (_currentTextureSet + 1) % kNumTextureSets;
   return YES;
 }
 
 @end