iOS: Add interface for injecting custom shaders

webrtc/sdk/objc/Framework/Classes/UI/RTCNSGLVideoView.m

 /*
  *  Copyright 2015 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 <Foundation/Foundation.h>
 
 #if !TARGET_OS_IPHONE
 
 #import "WebRTC/RTCNSGLVideoView.h"
 
 #import <AppKit/NSOpenGL.h>
 #import <CoreVideo/CVDisplayLink.h>
 #import <OpenGL/gl3.h>
 
-#import "RTCShader+Private.h"
+#import "RTCDefaultShader.h"
+#import "RTCI420TextureCache.h"
 #import "WebRTC/RTCLogging.h"
 #import "WebRTC/RTCVideoFrame.h"
 
 @interface RTCNSGLVideoView ()
 // |videoFrame| is set when we receive a frame from a worker thread and is read
 // from the display link callback so atomicity is required.
 @property(atomic, strong) RTCVideoFrame *videoFrame;
-@property(atomic, strong) id<RTCShader> i420Shader;
+@property(atomic, strong) RTCI420TextureCache *i420TextureCache;
 
 - (void)drawFrame;
 @end
 
 static CVReturn OnDisplayLinkFired(CVDisplayLinkRef displayLink,
                                    const CVTimeStamp *now,
                                    const CVTimeStamp *outputTime,
                                    CVOptionFlags flagsIn,
                                    CVOptionFlags *flagsOut,
                                    void *displayLinkContext) {
   RTCNSGLVideoView *view = (__bridge RTCNSGLVideoView *)displayLinkContext;
   [view drawFrame];
   return kCVReturnSuccess;
 }
 
 @implementation RTCNSGLVideoView {
   CVDisplayLinkRef _displayLink;
   RTCVideoFrame *_lastDrawnFrame;
+  id<RTCVideoViewShading> _shader;
 }
 
 @synthesize delegate = _delegate;
 @synthesize videoFrame = _videoFrame;
-@synthesize i420Shader = _i420Shader;
+@synthesize i420TextureCache = _i420TextureCache;
+
+- (instancetype)initWithFrame:(NSRect)frame pixelFormat:(NSOpenGLPixelFormat *)format {
+  return [self initWithFrame:frame pixelFormat:format shader:[[RTCDefaultShader alloc] init]];
+}
+
+- (instancetype)initWithFrame:(NSRect)frame
+                  pixelFormat:(NSOpenGLPixelFormat *)format
+                       shader:(id<RTCVideoViewShading>)shader {
+  if (self = [super initWithFrame:frame pixelFormat:format]) {
+    _shader = shader;
+  }
+  return self;
+}
 
 - (void)dealloc {
   [self teardownDisplayLink];
 }
 
 - (void)drawRect:(NSRect)rect {
   [self drawFrame];
 }
 
 - (void)reshape {
@@ skipping 15 matching lines @@
 
 - (void)prepareOpenGL {
   [super prepareOpenGL];
   [self ensureGLContext];
   glDisable(GL_DITHER);
   [self setupDisplayLink];
 }
 
 - (void)clearGLContext {
   [self ensureGLContext];
-  self.i420Shader = nil;
+  self.i420TextureCache = nil;
   [super clearGLContext];
 }
 
 #pragma mark - RTCVideoRenderer
 
 // These methods may be called on non-main thread.
 - (void)setSize:(CGSize)size {
   dispatch_async(dispatch_get_main_queue(), ^{
     [self.delegate videoView:self didChangeVideoSize:size];
   });
@@ skipping 12 matching lines @@
   }
   // This method may be called from CVDisplayLink callback which isn't on the
   // main thread so we have to lock the GL context before drawing.
   NSOpenGLContext *context = [self openGLContext];
   CGLLockContext([context CGLContextObj]);
 
   [self ensureGLContext];
   glClear(GL_COLOR_BUFFER_BIT);
 
   // Rendering native CVPixelBuffer is not supported on OS X.
+  // TODO(magjed): Add support for NV12 texture cache on OS X.
   frame = [frame newI420VideoFrame];
-  if (!self.i420Shader) {
-    self.i420Shader = [[RTCI420Shader alloc] initWithContext:context];
+  if (!self.i420TextureCache) {
+    self.i420TextureCache = [[RTCI420TextureCache alloc] initWithContext:context];
   }
-  if (self.i420Shader && [self.i420Shader drawFrame:frame]) {
+  RTCI420TextureCache *i420TextureCache = self.i420TextureCache;
+  if (i420TextureCache) {
+    [i420TextureCache uploadFrameToTextures:frame];
+    [_shader applyShadingForFrameWithRotation:frame.rotation
+                                       yPlane:i420TextureCache.yTexture
+                                       uPlane:i420TextureCache.uTexture
+                                       vPlane:i420TextureCache.vTexture];
     [context flushBuffer];
     _lastDrawnFrame = frame;
-  } else {
-    RTCLog(@"Failed to draw frame.");
   }
   CGLUnlockContext([context CGLContextObj]);
 }
 
 - (void)setupDisplayLink {
   if (_displayLink) {
     return;
   }
   // Synchronize buffer swaps with vertical refresh rate.
   GLint swapInt = 1;
@@ skipping 24 matching lines @@
   NSOpenGLContext* context = [self openGLContext];
   NSAssert(context, @"context shouldn't be nil");
   if ([NSOpenGLContext currentContext] != context) {
     [context makeCurrentContext];
   }
 }
 
 @end
 
 #endif  // !TARGET_OS_IPHONE