iOS: Add interface for injecting custom shaders

webrtc/sdk/objc/Framework/Classes/RTCEAGLVideoView.m

Index: webrtc/sdk/objc/Framework/Classes/RTCEAGLVideoView.m
diff --git a/webrtc/sdk/objc/Framework/Classes/RTCEAGLVideoView.m b/webrtc/sdk/objc/Framework/Classes/RTCEAGLVideoView.m
index 1fb03bc909e27305eee7eb41bd9f6066983f7e3e..0cccbface2122d3bb1c85eb872007610db778dc9 100644
--- a/webrtc/sdk/objc/Framework/Classes/RTCEAGLVideoView.m
+++ b/webrtc/sdk/objc/Framework/Classes/RTCEAGLVideoView.m
@@ -12,7 +12,9 @@
 
 #import <GLKit/GLKit.h>
 
-#import "RTCShader+Private.h"
+#import "RTCI420TextureCache.h"
+#import "RTCNV12TextureCache.h"
+#import "RTCDefaultShaderDelegate.h"
 #import "WebRTC/RTCLogging.h"
 #import "WebRTC/RTCVideoFrame.h"
 
@@ -97,8 +99,10 @@
   // This flag should only be set and read on the main thread (e.g. by
   // setNeedsDisplay)
   BOOL _isDirty;
-  id<RTCShader> _i420Shader;
-  id<RTCShader> _nv12Shader;
+  RTCDefaultShaderDelegate *_defaultShaderDelegate;

[daniela-webrtc, 2017/05/11 17:31:20]

I find this slightly confusing.  When is the defaultShaderDelegate used?

[magjed_webrtc, 2017/05/25 14:26:45]

I added a comment:
|_defaultShaderDelegate| is used only when no external shader is provided in the
init function, and the only purpose is to keep the shader alive by having a
strong reference. Shaders will only be accessed through |_shaderDelegate|.

+  __weak id<RTCVideoViewShaderDelegate> _shaderDelegate;
+  RTCNV12TextureCache* _nv12TextureCache;
+  RTCI420TextureCache* _i420TextureCache;
   RTCVideoFrame *_lastDrawnFrame;
 }
 
@@ -107,14 +111,28 @@
 @synthesize glkView = _glkView;
 
 - (instancetype)initWithFrame:(CGRect)frame {
+  _defaultShaderDelegate = [[RTCDefaultShaderDelegate alloc] init];
+  return [self initWithFrame:frame shaderDelegate:_defaultShaderDelegate];
+}
+
+- (instancetype)initWithCoder:(NSCoder *)aDecoder {
+  _defaultShaderDelegate = [[RTCDefaultShaderDelegate alloc] init];
+  return [self initWithCoder:aDecoder shaderDelegate:_defaultShaderDelegate];
+}
+
+- (instancetype)initWithFrame:(CGRect)frame
+               shaderDelegate:(id<RTCVideoViewShaderDelegate>)shaderDelegate {
   if (self = [super initWithFrame:frame]) {
+    _shaderDelegate = shaderDelegate;
     [self configure];
   }
   return self;
 }
 
-- (instancetype)initWithCoder:(NSCoder *)aDecoder {
+- (instancetype)initWithCoder:(NSCoder *)aDecoder
+               shaderDelegate:(id<RTCVideoViewShaderDelegate>)shaderDelegate {
   if (self = [super initWithCoder:aDecoder]) {
+    _shaderDelegate = shaderDelegate;
     [self configure];
   }
   return self;
@@ -207,22 +225,28 @@
   }
   [self ensureGLContext];
   glClear(GL_COLOR_BUFFER_BIT);
-  id<RTCShader> shader = nil;
   if (frame.nativeHandle) {
-    if (!_nv12Shader) {
-      _nv12Shader = [[RTCNativeNV12Shader alloc] initWithContext:_glContext];
+    if (!_nv12TextureCache) {
+      _nv12TextureCache = [[RTCNV12TextureCache alloc] initWithContext:_glContext];
     }
-    shader = _nv12Shader;
-  } else {
-    if (!_i420Shader) {
-      _i420Shader = [[RTCI420Shader alloc] initWithContext:_glContext];
+    if (_nv12TextureCache) {
+      [_nv12TextureCache uploadFrameToTextures:frame];
+      [_shaderDelegate videoView:self

[daniela-webrtc, 2017/05/11 17:31:20]

What if this is nil? Shouldn't the defaultDelegate be used here?

+          didReceiveFrameWithRotation:frame.rotation
+                               yPlane:_nv12TextureCache.yTexture
+                              uvPlane:_nv12TextureCache.uvTexture];
+      [_nv12TextureCache releaseTextures];
     }
-    shader = _i420Shader;
-  }
-  if (shader && [shader drawFrame:frame]) {
-    _lastDrawnFrame = frame;
   } else {
-    RTCLog(@"Failed to draw frame.");
+    if (!_i420TextureCache) {
+      _i420TextureCache = [[RTCI420TextureCache alloc] initWithContext:_glContext];
+    }
+    [_i420TextureCache uploadFrameToTextures:frame];
+    [_shaderDelegate videoView:self
+        didReceiveFrameWithRotation:frame.rotation
+                             yPlane:_i420TextureCache.yTexture
+                             uPlane:_i420TextureCache.uTexture
+                             vPlane:_i420TextureCache.vTexture];
   }
 }
 
@@ -275,8 +299,9 @@
   _timer.isPaused = YES;
   [_glkView deleteDrawable];
   [self ensureGLContext];
-  _i420Shader = nil;
-  _nv12Shader = nil;
+  _nv12TextureCache = nil;
+  _i420TextureCache = nil;
+  _defaultShaderDelegate = nil;
 }
 
 - (void)didBecomeActive {