/* |
File: OpenGLPixelBufferView.m |
Abstract: The OpenGL ES view. |
Version: 2.2 |
|
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Copyright (C) 2014 Apple Inc. All Rights Reserved. |
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*/ |
|
#import "OpenGLPixelBufferView.h" |
#import <OpenGLES/EAGL.h> |
#import <QuartzCore/CAEAGLLayer.h> |
#import "ShaderUtilities.h" |
|
#if !defined(_STRINGIFY) |
#define __STRINGIFY( _x ) # _x |
#define _STRINGIFY( _x ) __STRINGIFY( _x ) |
#endif |
|
static const char * kPassThruVertex = _STRINGIFY( |
|
attribute vec4 position; |
attribute mediump vec4 texturecoordinate; |
varying mediump vec2 coordinate; |
|
void main() |
{ |
gl_Position = position; |
coordinate = texturecoordinate.xy; |
} |
|
); |
|
static const char * kPassThruFragment = _STRINGIFY( |
|
varying highp vec2 coordinate; |
uniform sampler2D videoframe; |
|
void main() |
{ |
gl_FragColor = texture2D(videoframe, coordinate); |
} |
|
); |
|
enum { |
ATTRIB_VERTEX, |
ATTRIB_TEXTUREPOSITON, |
NUM_ATTRIBUTES |
}; |
|
@interface OpenGLPixelBufferView () |
{ |
EAGLContext* _oglContext; |
CVOpenGLESTextureCacheRef _textureCache; |
GLint _width; |
GLint _height; |
GLuint _frameBufferHandle; |
GLuint _colorBufferHandle; |
GLuint _program; |
GLint _frame; |
} |
|
- (BOOL)initializeBuffers; |
- (void)reset; |
|
@end |
|
@implementation OpenGLPixelBufferView |
|
+ (Class)layerClass |
{ |
return [CAEAGLLayer class]; |
} |
|
-(id)initWithFrame:(CGRect)frame |
{ |
self = [super initWithFrame:frame]; |
if (self != nil) { |
// Use 2x scale factor on Retina displays. |
self.contentScaleFactor = [[UIScreen mainScreen] scale]; |
|
// Initialize OpenGL ES 2 |
CAEAGLLayer* eaglLayer = (CAEAGLLayer *)self.layer; |
eaglLayer.opaque = YES; |
eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys: |
[NSNumber numberWithBool:NO], kEAGLDrawablePropertyRetainedBacking, |
kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat, |
nil]; |
|
self->_oglContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2]; |
if (!self->_oglContext) { |
NSLog(@"Problem with OpenGL context."); |
[self release]; |
return nil; |
} |
} |
return self; |
} |
|
- (BOOL)initializeBuffers |
{ |
BOOL success = YES; |
|
glDisable(GL_DEPTH_TEST); |
|
glGenFramebuffers(1, &_frameBufferHandle); |
glBindFramebuffer(GL_FRAMEBUFFER, _frameBufferHandle); |
|
glGenRenderbuffers(1, &_colorBufferHandle); |
glBindRenderbuffer(GL_RENDERBUFFER, _colorBufferHandle); |
|
[_oglContext renderbufferStorage:GL_RENDERBUFFER fromDrawable:(CAEAGLLayer *)self.layer]; |
|
glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &_width); |
glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &_height); |
|
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, _colorBufferHandle); |
if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) { |
NSLog(@"Failure with framebuffer generation"); |
success = NO; |
goto bail; |
} |
|
// Create a new CVOpenGLESTexture cache |
CVReturn err = CVOpenGLESTextureCacheCreate(kCFAllocatorDefault, NULL, _oglContext, NULL, &_textureCache); |
if (err) { |
NSLog(@"Error at CVOpenGLESTextureCacheCreate %d", err); |
success = NO; |
goto bail; |
} |
|
// attributes |
GLint attribLocation[NUM_ATTRIBUTES] = { |
ATTRIB_VERTEX, ATTRIB_TEXTUREPOSITON, |
}; |
GLchar *attribName[NUM_ATTRIBUTES] = { |
"position", "texturecoordinate", |
}; |
|
glueCreateProgram(kPassThruVertex, kPassThruFragment, |
NUM_ATTRIBUTES, (const GLchar **)&attribName[0], attribLocation, |
0, 0, 0, |
&_program); |
|
if (!_program) { |
NSLog(@"Error creating the program"); |
success = NO; |
goto bail; |
} |
_frame = glueGetUniformLocation(_program, "videoframe"); |
bail: |
if (!success) { |
[self reset]; |
} |
return success; |
} |
|
- (void)reset |
{ |
EAGLContext *oldContext = [EAGLContext currentContext]; |
if (oldContext != _oglContext) { |
if (![EAGLContext setCurrentContext:_oglContext]) { |
@throw [NSException exceptionWithName:NSInternalInconsistencyException reason:@"Problem with OpenGL context" userInfo:nil]; |
return; |
} |
} |
if (_frameBufferHandle) { |
glDeleteFramebuffers(1, &_frameBufferHandle); |
_frameBufferHandle = 0; |
} |
if (_colorBufferHandle) { |
glDeleteRenderbuffers(1, &_colorBufferHandle); |
_colorBufferHandle = 0; |
} |
if (_program) { |
glDeleteProgram(_program); |
_program = 0; |
} |
if (_textureCache) { |
CFRelease(_textureCache); |
_textureCache = 0; |
} |
if (oldContext != _oglContext) { |
[EAGLContext setCurrentContext:oldContext]; |
} |
} |
|
- (void)dealloc |
{ |
[self reset]; |
[_oglContext release]; |
[super dealloc]; |
} |
|
- (void)displayPixelBuffer:(CVPixelBufferRef)pixelBuffer |
{ |
static const GLfloat squareVertices[] = { |
-1.0f, -1.0f, // bottom left |
1.0f, -1.0f, // bottom right |
-1.0f, 1.0f, // top left |
1.0f, 1.0f, // top right |
}; |
|
if (NULL == pixelBuffer) { |
@throw [NSException exceptionWithName:NSInvalidArgumentException reason:@"NULL pixel buffer" userInfo:nil]; |
return; |
} |
|
EAGLContext *oldContext = [EAGLContext currentContext]; |
if (oldContext != _oglContext) { |
if (![EAGLContext setCurrentContext:_oglContext]) { |
@throw [NSException exceptionWithName:NSInternalInconsistencyException reason:@"Problem with OpenGL context" userInfo:nil]; |
return; |
} |
} |
|
if (0 == _frameBufferHandle) { |
BOOL success = [self initializeBuffers]; |
if ( !success ) { |
NSLog(@"Problem initializing OpenGL buffers."); |
return; |
} |
} |
|
// Create a CVOpenGLESTexture from a CVPixelBufferRef |
size_t frameWidth = CVPixelBufferGetWidth(pixelBuffer); |
size_t frameHeight = CVPixelBufferGetHeight(pixelBuffer); |
CVOpenGLESTextureRef texture = NULL; |
CVReturn err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault, |
_textureCache, |
pixelBuffer, |
NULL, |
GL_TEXTURE_2D, |
GL_RGBA, |
(GLsizei)frameWidth, |
(GLsizei)frameHeight, |
GL_BGRA, |
GL_UNSIGNED_BYTE, |
0, |
&texture); |
|
|
if (!texture || err) { |
NSLog(@"CVOpenGLESTextureCacheCreateTextureFromImage failed (error: %d)", err); |
return; |
} |
|
// Set the view port to the entire view |
glBindFramebuffer(GL_FRAMEBUFFER, _frameBufferHandle); |
glViewport(0, 0, _width, _height); |
|
glUseProgram(_program); |
glActiveTexture(GL_TEXTURE0); |
glBindTexture(CVOpenGLESTextureGetTarget(texture), CVOpenGLESTextureGetName(texture)); |
glUniform1i(_frame, 0); |
|
// Set texture parameters |
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); |
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); |
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); |
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); |
|
glVertexAttribPointer(ATTRIB_VERTEX, 2, GL_FLOAT, 0, 0, squareVertices); |
glEnableVertexAttribArray(ATTRIB_VERTEX); |
|
// Preserve aspect ratio; fill layer bounds |
CGSize textureSamplingSize; |
CGSize cropScaleAmount = CGSizeMake(self.bounds.size.width / (float)frameWidth, self.bounds.size.height / (float)frameHeight); |
if ( cropScaleAmount.height > cropScaleAmount.width ) { |
textureSamplingSize.width = self.bounds.size.width / (frameWidth * cropScaleAmount.height); |
textureSamplingSize.height = 1.0; |
} |
else { |
textureSamplingSize.width = 1.0; |
textureSamplingSize.height = self.bounds.size.height / (frameHeight * cropScaleAmount.width); |
} |
|
// Perform a vertical flip by swapping the top left and the bottom left coordinate. |
// CVPixelBuffers have a top left origin and OpenGL has a bottom left origin. |
GLfloat passThroughTextureVertices[] = { |
(1.0 - textureSamplingSize.width)/2.0, (1.0 + textureSamplingSize.height)/2.0, // top left |
(1.0 + textureSamplingSize.width)/2.0, (1.0 + textureSamplingSize.height)/2.0, // top right |
(1.0 - textureSamplingSize.width)/2.0, (1.0 - textureSamplingSize.height)/2.0, // bottom left |
(1.0 + textureSamplingSize.width)/2.0, (1.0 - textureSamplingSize.height)/2.0, // bottom right |
}; |
|
glVertexAttribPointer(ATTRIB_TEXTUREPOSITON, 2, GL_FLOAT, 0, 0, passThroughTextureVertices); |
glEnableVertexAttribArray(ATTRIB_TEXTUREPOSITON); |
|
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); |
|
glBindRenderbuffer(GL_RENDERBUFFER, _colorBufferHandle); |
[_oglContext presentRenderbuffer:GL_RENDERBUFFER]; |
|
glBindTexture(CVOpenGLESTextureGetTarget(texture), 0); |
glBindTexture(GL_TEXTURE_2D, 0); |
CFRelease(texture); |
|
if (oldContext != _oglContext) { |
[EAGLContext setCurrentContext:oldContext]; |
} |
} |
|
- (void)flushPixelBufferCache |
{ |
if (_textureCache) { |
CVOpenGLESTextureCacheFlush(_textureCache, 0); |
} |
} |
|
@end |
