1 files changed, 259 insertions, 0 deletions
diff --git a/webrtc/api/objc/RTCEAGLVideoView.m b/webrtc/api/objc/RTCEAGLVideoView.m
new file mode 100644
index 0000000000..e664ede455
--- /dev/null
+++ b/webrtc/api/objc/RTCEAGLVideoView.m
@@ -0,0 +1,259 @@
+/*
+ *  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 "RTCEAGLVideoView.h"
+
+#import <GLKit/GLKit.h>
+
+#import "RTCVideoFrame.h"
+#import "RTCOpenGLVideoRenderer.h"
+
+// RTCDisplayLinkTimer wraps a CADisplayLink and is set to fire every two screen
+// refreshes, which should be 30fps. We wrap the display link in order to avoid
+// a retain cycle since CADisplayLink takes a strong reference onto its target.
+// The timer is paused by default.
+@interface RTCDisplayLinkTimer : NSObject
+
+@property(nonatomic) BOOL isPaused;
+
+- (instancetype)initWithTimerHandler:(void (^)(void))timerHandler;
+- (void)invalidate;
+
+@end
+
+@implementation RTCDisplayLinkTimer {
+  CADisplayLink *_displayLink;
+  void (^_timerHandler)(void);
+}
+
+- (instancetype)initWithTimerHandler:(void (^)(void))timerHandler {
+  NSParameterAssert(timerHandler);
+  if (self = [super init]) {
+    _timerHandler = timerHandler;
+    _displayLink =
+        [CADisplayLink displayLinkWithTarget:self
+                                    selector:@selector(displayLinkDidFire:)];
+    _displayLink.paused = YES;
+    // Set to half of screen refresh, which should be 30fps.
+    [_displayLink setFrameInterval:2];
+    [_displayLink addToRunLoop:[NSRunLoop currentRunLoop]
+                       forMode:NSRunLoopCommonModes];
+  }
+  return self;
+}
+
+- (void)dealloc {
+  [self invalidate];
+}
+
+- (BOOL)isPaused {
+  return _displayLink.paused;
+}
+
+- (void)setIsPaused:(BOOL)isPaused {
+  _displayLink.paused = isPaused;
+}
+
+- (void)invalidate {
+  [_displayLink invalidate];
+}
+
+- (void)displayLinkDidFire:(CADisplayLink *)displayLink {
+  _timerHandler();
+}
+
+@end
+
+// RTCEAGLVideoView wraps a GLKView which is setup with
+// enableSetNeedsDisplay = NO for the purpose of gaining control of
+// exactly when to call -[GLKView display]. This need for extra
+// control is required to avoid triggering method calls on GLKView
+// that results in attempting to bind the underlying render buffer
+// when the drawable size would be empty which would result in the
+// error GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT. -[GLKView display] is
+// the method that will trigger the binding of the render
+// buffer. Because the standard behaviour of -[UIView setNeedsDisplay]
+// is disabled for the reasons above, the RTCEAGLVideoView maintains
+// its own |isDirty| flag.
+
+@interface RTCEAGLVideoView () <GLKViewDelegate>
+// |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(nonatomic, readonly) GLKView *glkView;
+@property(nonatomic, readonly) RTCOpenGLVideoRenderer *glRenderer;
+@end
+
+@implementation RTCEAGLVideoView {
+  RTCDisplayLinkTimer *_timer;
+  // This flag should only be set and read on the main thread (e.g. by
+  // setNeedsDisplay)
+  BOOL _isDirty;
+}
+
+@synthesize delegate = _delegate;
+@synthesize videoFrame = _videoFrame;
+@synthesize glkView = _glkView;
+@synthesize glRenderer = _glRenderer;
+
+- (instancetype)initWithFrame:(CGRect)frame {
+  if (self = [super initWithFrame:frame]) {
+    [self configure];
+  }
+  return self;
+}
+
+- (instancetype)initWithCoder:(NSCoder *)aDecoder {
+  if (self = [super initWithCoder:aDecoder]) {
+    [self configure];
+  }
+  return self;
+}
+
+- (void)configure {
+  EAGLContext *glContext =
+    [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES3];
+  if (!glContext) {
+    glContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
+  }
+  _glRenderer = [[RTCOpenGLVideoRenderer alloc] initWithContext:glContext];
+
+  // GLKView manages a framebuffer for us.
+  _glkView = [[GLKView alloc] initWithFrame:CGRectZero
+                                    context:glContext];
+  _glkView.drawableColorFormat = GLKViewDrawableColorFormatRGBA8888;
+  _glkView.drawableDepthFormat = GLKViewDrawableDepthFormatNone;
+  _glkView.drawableStencilFormat = GLKViewDrawableStencilFormatNone;
+  _glkView.drawableMultisample = GLKViewDrawableMultisampleNone;
+  _glkView.delegate = self;
+  _glkView.layer.masksToBounds = YES;
+  _glkView.enableSetNeedsDisplay = NO;
+  [self addSubview:_glkView];
+
+  // Listen to application state in order to clean up OpenGL before app goes
+  // away.
+  NSNotificationCenter *notificationCenter =
+    [NSNotificationCenter defaultCenter];
+  [notificationCenter addObserver:self
+                         selector:@selector(willResignActive)
+                             name:UIApplicationWillResignActiveNotification
+                           object:nil];
+  [notificationCenter addObserver:self
+                         selector:@selector(didBecomeActive)
+                             name:UIApplicationDidBecomeActiveNotification
+                           object:nil];
+
+  // Frames are received on a separate thread, so we poll for current frame
+  // using a refresh rate proportional to screen refresh frequency. This
+  // occurs on the main thread.
+  __weak RTCEAGLVideoView *weakSelf = self;
+  _timer = [[RTCDisplayLinkTimer alloc] initWithTimerHandler:^{
+      RTCEAGLVideoView *strongSelf = weakSelf;
+      [strongSelf displayLinkTimerDidFire];
+    }];
+  [self setupGL];
+}
+
+- (void)dealloc {
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
+  UIApplicationState appState =
+      [UIApplication sharedApplication].applicationState;
+  if (appState == UIApplicationStateActive) {
+    [self teardownGL];
+  }
+  [_timer invalidate];
+}
+
+#pragma mark - UIView
+
+- (void)setNeedsDisplay {
+  [super setNeedsDisplay];
+  _isDirty = YES;
+}
+
+- (void)setNeedsDisplayInRect:(CGRect)rect {
+  [super setNeedsDisplayInRect:rect];
+  _isDirty = YES;
+}
+
+- (void)layoutSubviews {
+  [super layoutSubviews];
+  _glkView.frame = self.bounds;
+}
+
+#pragma mark - GLKViewDelegate
+
+// This method is called when the GLKView's content is dirty and needs to be
+// redrawn. This occurs on main thread.
+- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect {
+  // The renderer will draw the frame to the framebuffer corresponding to the
+  // one used by |view|.
+  [_glRenderer drawFrame:self.videoFrame];
+}
+
+#pragma mark - RTCVideoRenderer
+
+// These methods may be called on non-main thread.
+- (void)setSize:(CGSize)size {
+  __weak RTCEAGLVideoView *weakSelf = self;
+  dispatch_async(dispatch_get_main_queue(), ^{
+    RTCEAGLVideoView *strongSelf = weakSelf;
+    [strongSelf.delegate videoView:strongSelf didChangeVideoSize:size];
+  });
+}
+
+- (void)renderFrame:(RTCVideoFrame *)frame {
+  self.videoFrame = frame;
+}
+
+#pragma mark - Private
+
+- (void)displayLinkTimerDidFire {
+  // Don't render unless video frame have changed or the view content
+  // has explicitly been marked dirty.
+  if (!_isDirty && _glRenderer.lastDrawnFrame == self.videoFrame) {
+    return;
+  }
+
+  // Always reset isDirty at this point, even if -[GLKView display]
+  // won't be called in the case the drawable size is empty.
+  _isDirty = NO;
+
+  // Only call -[GLKView display] if the drawable size is
+  // non-empty. Calling display will make the GLKView setup its
+  // render buffer if necessary, but that will fail with error
+  // GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT if size is empty.
+  if (self.bounds.size.width > 0 && self.bounds.size.height > 0) {
+    [_glkView display];
+  }
+}
+
+- (void)setupGL {
+  self.videoFrame = nil;
+  [_glRenderer setupGL];
+  _timer.isPaused = NO;
+}
+
+- (void)teardownGL {
+  self.videoFrame = nil;
+  _timer.isPaused = YES;
+  [_glkView deleteDrawable];
+  [_glRenderer teardownGL];
+}
+
+- (void)didBecomeActive {
+  [self setupGL];
+}
+
+- (void)willResignActive {
+  [self teardownGL];
+}
+
+@end