1/*
2 * libjingle
3 * Copyright 2014 Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 *  1. Redistributions of source code must retain the above copyright notice,
9 *     this list of conditions and the following disclaimer.
10 *  2. Redistributions in binary form must reproduce the above copyright notice,
11 *     this list of conditions and the following disclaimer in the documentation
12 *     and/or other materials provided with the distribution.
13 *  3. The name of the author may not be used to endorse or promote products
14 *     derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#if !defined(__has_feature) || !__has_feature(objc_arc)
29#error "This file requires ARC support."
30#endif
31
32#import "RTCNSGLVideoView.h"
33
34#import <CoreVideo/CVDisplayLink.h>
35#import <OpenGL/gl3.h>
36#import "RTCI420Frame.h"
37#import "RTCOpenGLVideoRenderer.h"
38
39@interface RTCNSGLVideoView ()
40// |i420Frame| is set when we receive a frame from a worker thread and is read
41// from the display link callback so atomicity is required.
42@property(atomic, strong) RTCI420Frame* i420Frame;
43@property(atomic, strong) RTCOpenGLVideoRenderer* glRenderer;
44- (void)drawFrame;
45@end
46
47static CVReturn OnDisplayLinkFired(CVDisplayLinkRef displayLink,
48                                   const CVTimeStamp* now,
49                                   const CVTimeStamp* outputTime,
50                                   CVOptionFlags flagsIn,
51                                   CVOptionFlags* flagsOut,
52                                   void* displayLinkContext) {
53  RTCNSGLVideoView* view = (__bridge RTCNSGLVideoView*)displayLinkContext;
54  [view drawFrame];
55  return kCVReturnSuccess;
56}
57
58@implementation RTCNSGLVideoView {
59  CVDisplayLinkRef _displayLink;
60}
61
62- (void)dealloc {
63  [self teardownDisplayLink];
64}
65
66- (void)drawRect:(NSRect)rect {
67  [self drawFrame];
68}
69
70- (void)reshape {
71  [super reshape];
72  NSRect frame = [self frame];
73  CGLLockContext([[self openGLContext] CGLContextObj]);
74  glViewport(0, 0, frame.size.width, frame.size.height);
75  CGLUnlockContext([[self openGLContext] CGLContextObj]);
76}
77
78- (void)lockFocus {
79  NSOpenGLContext* context = [self openGLContext];
80  [super lockFocus];
81  if ([context view] != self) {
82    [context setView:self];
83  }
84  [context makeCurrentContext];
85}
86
87- (void)prepareOpenGL {
88  [super prepareOpenGL];
89  if (!self.glRenderer) {
90    self.glRenderer =
91        [[RTCOpenGLVideoRenderer alloc] initWithContext:[self openGLContext]];
92  }
93  [self.glRenderer setupGL];
94  [self setupDisplayLink];
95}
96
97- (void)clearGLContext {
98  [self.glRenderer teardownGL];
99  self.glRenderer = nil;
100  [super clearGLContext];
101}
102
103#pragma mark - RTCVideoRenderer
104
105// These methods may be called on non-main thread.
106- (void)setSize:(CGSize)size {
107  dispatch_async(dispatch_get_main_queue(), ^{
108    [self.delegate videoView:self didChangeVideoSize:size];
109  });
110}
111
112- (void)renderFrame:(RTCI420Frame*)frame {
113  self.i420Frame = frame;
114}
115
116#pragma mark - Private
117
118- (void)drawFrame {
119  RTCI420Frame* i420Frame = self.i420Frame;
120  if (self.glRenderer.lastDrawnFrame != i420Frame) {
121    // This method may be called from CVDisplayLink callback which isn't on the
122    // main thread so we have to lock the GL context before drawing.
123    CGLLockContext([[self openGLContext] CGLContextObj]);
124    [self.glRenderer drawFrame:i420Frame];
125    CGLUnlockContext([[self openGLContext] CGLContextObj]);
126  }
127}
128
129- (void)setupDisplayLink {
130  if (_displayLink) {
131    return;
132  }
133  // Synchronize buffer swaps with vertical refresh rate.
134  GLint swapInt = 1;
135  [[self openGLContext] setValues:&swapInt forParameter:NSOpenGLCPSwapInterval];
136
137  // Create display link.
138  CVDisplayLinkCreateWithActiveCGDisplays(&_displayLink);
139  CVDisplayLinkSetOutputCallback(_displayLink,
140                                 &OnDisplayLinkFired,
141                                 (__bridge void*)self);
142  // Set the display link for the current renderer.
143  CGLContextObj cglContext = [[self openGLContext] CGLContextObj];
144  CGLPixelFormatObj cglPixelFormat = [[self pixelFormat] CGLPixelFormatObj];
145  CVDisplayLinkSetCurrentCGDisplayFromOpenGLContext(
146      _displayLink, cglContext, cglPixelFormat);
147  CVDisplayLinkStart(_displayLink);
148}
149
150- (void)teardownDisplayLink {
151  if (!_displayLink) {
152    return;
153  }
154  CVDisplayLinkRelease(_displayLink);
155  _displayLink = NULL;
156}
157
158@end
159