framework/Source/Mac/GPUImageView.m
#import "GPUImageView.h"
#import <QuartzCore/QuartzCore.h>
#import "GPUImageContext.h"
#import "GPUImageFilter.h"
#import <AVFoundation/AVFoundation.h>

#pragma mark -
#pragma mark Private methods and instance variables

@interface GPUImageView () 
{
    GPUImageFramebuffer *inputFramebufferForDisplay;

    GLProgram *displayProgram;
    GLint displayPositionAttribute, displayTextureCoordinateAttribute;
    GLint displayInputTextureUniform;
    
    CGSize inputImageSize;
    GLfloat imageVertices[8];
    GLfloat backgroundColorRed, backgroundColorGreen, backgroundColorBlue, backgroundColorAlpha;
}

// Initialization and teardown
- (void)commonInit;

// Managing the display FBOs
- (void)createDisplayFramebuffer;
- (void)destroyDisplayFramebuffer;

// Handling fill mode
- (void)recalculateViewGeometry;

@end

@implementation GPUImageView

@synthesize sizeInPixels = _sizeInPixels;
@synthesize fillMode = _fillMode;
@synthesize enabled;

#pragma mark -
#pragma mark Initialization and teardown

- (id)initWithFrame:(CGRect)frame
{
    if (!(self = [super initWithFrame:frame]))
    {
		return nil;
    }
    
    [self commonInit];
    
    return self;
}

-(id)initWithCoder:(NSCoder *)coder
{
	if (!(self = [super initWithCoder:coder])) 
    {
        return nil;
	}

    [self commonInit];

	return self;
}

- (void)commonInit;
{
    [self setOpenGLContext:[[GPUImageContext sharedImageProcessingContext] context]];

    if ([self respondsToSelector:@selector(setWantsBestResolutionOpenGLSurface:)])
    {
        [self  setWantsBestResolutionOpenGLSurface:YES];
    }
    
    inputRotation = kGPUImageNoRotation;
    self.hidden = NO;

    self.enabled = YES;
    
    runSynchronouslyOnVideoProcessingQueue(^{
        [GPUImageContext useImageProcessingContext];
        displayProgram = [[GPUImageContext sharedImageProcessingContext] programForVertexShaderString:kGPUImageVertexShaderString fragmentShaderString:kGPUImagePassthroughFragmentShaderString];

        if (!displayProgram.initialized)
        {
            [displayProgram addAttribute:@"position"];
            [displayProgram addAttribute:@"inputTextureCoordinate"];
            
            if (![displayProgram link])
            {
                NSString *progLog = [displayProgram programLog];
                NSLog(@"Program link log: %@", progLog);
                NSString *fragLog = [displayProgram fragmentShaderLog];
                NSLog(@"Fragment shader compile log: %@", fragLog);
                NSString *vertLog = [displayProgram vertexShaderLog];
                NSLog(@"Vertex shader compile log: %@", vertLog);
                displayProgram = nil;
                NSAssert(NO, @"Filter shader link failed");
            }
        }
        
        displayPositionAttribute = [displayProgram attributeIndex:@"position"];
        displayTextureCoordinateAttribute = [displayProgram attributeIndex:@"inputTextureCoordinate"];
        displayInputTextureUniform = [displayProgram uniformIndex:@"inputImageTexture"];
        
        [GPUImageContext setActiveShaderProgram:displayProgram];

        glEnableVertexAttribArray(displayPositionAttribute);
        glEnableVertexAttribArray(displayTextureCoordinateAttribute);
    
        [self setBackgroundColorRed:0.0 green:0.0 blue:0.0 alpha:1.0];
        _fillMode = kGPUImageFillModePreserveAspectRatio;
        [self createDisplayFramebuffer];
    });
    
}

- (void)dealloc
{
}

#pragma mark -
#pragma mark Managing the display FBOs

- (void)createDisplayFramebuffer;
{
    // Perhaps I'll use an FBO at some time later, but for now will render directly to the screen
    if ([self respondsToSelector:@selector(convertSizeToBacking:)])
    {
        _sizeInPixels = [self convertSizeToBacking:self.bounds.size];
    }
    else
    {
        _sizeInPixels = self.bounds.size;
    }
}

- (void)destroyDisplayFramebuffer;
{
    [self.openGLContext makeCurrentContext];
}

- (void)setDisplayFramebuffer;
{
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    glBindRenderbuffer(GL_RENDERBUFFER, 0);
    
    glViewport(0, 0, (GLint)_sizeInPixels.width, (GLint)_sizeInPixels.height);
}

- (void)presentFramebuffer;
{
    [self.openGLContext flushBuffer];
}

- (void)reshape;
{
    CGSize viewSize = self.bounds.size;
    if ([self respondsToSelector:@selector(convertSizeToBacking:)])
    {
        viewSize = [self convertSizeToBacking:self.bounds.size];
    }
    
    if ( (_sizeInPixels.width == viewSize.width) && (_sizeInPixels.height == viewSize.height) )
    {
        return;
    }
    
    _sizeInPixels = viewSize;

    [self recalculateViewGeometry];
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        [self newFrameReadyAtTime:kCMTimeInvalid atIndex:0];
    });
}

#pragma mark -
#pragma mark Handling fill mode

- (void)recalculateViewGeometry;
{
    CGFloat heightScaling, widthScaling;
    
    CGSize currentViewSize = self.sizeInPixels;

    if ((inputImageSize.width < 1.0) || (inputImageSize.height < 1.0))
    {
        return;
    }

    CGRect insetRect = AVMakeRectWithAspectRatioInsideRect(inputImageSize, CGRectMake(0.0,0.0,currentViewSize.width,currentViewSize.height));
    if ((insetRect.size.width < 1.0) || (insetRect.size.width < 1.0))
    {
        insetRect = CGRectMake(0.0,0.0,currentViewSize.width,currentViewSize.height);
    }
    
    switch(_fillMode)
    {
        case kGPUImageFillModeStretch:
        {
            widthScaling = 1.0;
            heightScaling = 1.0;
        }; break;
        case kGPUImageFillModePreserveAspectRatio:
        {
            widthScaling = insetRect.size.width / currentViewSize.width;
            heightScaling = insetRect.size.height / currentViewSize.height;
        }; break;
        case kGPUImageFillModePreserveAspectRatioAndFill:
        {
            widthScaling = currentViewSize.height / insetRect.size.height;
            heightScaling = currentViewSize.width / insetRect.size.width;
        }; break;
    }
    
    imageVertices[0] = -widthScaling;
    imageVertices[1] = -heightScaling;
    imageVertices[2] = widthScaling;
    imageVertices[3] = -heightScaling;
    imageVertices[4] = -widthScaling;
    imageVertices[5] = heightScaling;
    imageVertices[6] = widthScaling;
    imageVertices[7] = heightScaling;
}

- (void)setBackgroundColorRed:(GLfloat)redComponent green:(GLfloat)greenComponent blue:(GLfloat)blueComponent alpha:(GLfloat)alphaComponent;
{
    backgroundColorRed = redComponent;
    backgroundColorGreen = greenComponent;
    backgroundColorBlue = blueComponent;
    backgroundColorAlpha = alphaComponent;
}

+ (const GLfloat *)textureCoordinatesForRotation:(GPUImageRotationMode)rotationMode;
{
//    static const GLfloat noRotationTextureCoordinates[] = {
//        0.0f, 0.0f,
//        1.0f, 0.0f,
//        0.0f, 1.0f,
//        1.0f, 1.0f,
//    };
    
    static const GLfloat noRotationTextureCoordinates[] = {
        0.0f, 1.0f,
        1.0f, 1.0f,
        0.0f, 0.0f,
        1.0f, 0.0f,
    };

    static const GLfloat rotateRightTextureCoordinates[] = {
        1.0f, 1.0f,
        1.0f, 0.0f,
        0.0f, 1.0f,
        0.0f, 0.0f,
    };

    static const GLfloat rotateLeftTextureCoordinates[] = {
        0.0f, 0.0f,
        0.0f, 1.0f,
        1.0f, 0.0f,
        1.0f, 1.0f,
    };
        
    static const GLfloat verticalFlipTextureCoordinates[] = {
        0.0f, 0.0f,
        1.0f, 0.0f,
        0.0f, 1.0f,
        1.0f, 1.0f,
    };
    
    static const GLfloat horizontalFlipTextureCoordinates[] = {
        1.0f, 1.0f,
        0.0f, 1.0f,
        1.0f, 0.0f,
        0.0f, 0.0f,
    };
    
    static const GLfloat rotateRightVerticalFlipTextureCoordinates[] = {
        1.0f, 0.0f,
        1.0f, 1.0f,
        0.0f, 0.0f,
        0.0f, 1.0f,
    };
    
    static const GLfloat rotateRightHorizontalFlipTextureCoordinates[] = {
        1.0f, 1.0f,
        1.0f, 0.0f,
        0.0f, 1.0f,
        0.0f, 0.0f,
    };
    
    static const GLfloat rotate180TextureCoordinates[] = {
        1.0f, 0.0f,
        0.0f, 0.0f,
        1.0f, 1.0f,
        0.0f, 1.0f,
    };
    
    switch(rotationMode)
    {
        case kGPUImageNoRotation: return noRotationTextureCoordinates;
        case kGPUImageRotateLeft: return rotateLeftTextureCoordinates;
        case kGPUImageRotateRight: return rotateRightTextureCoordinates;
        case kGPUImageFlipVertical: return verticalFlipTextureCoordinates;
        case kGPUImageFlipHorizonal: return horizontalFlipTextureCoordinates;
        case kGPUImageRotateRightFlipVertical: return rotateRightVerticalFlipTextureCoordinates;
        case kGPUImageRotateRightFlipHorizontal: return rotateRightHorizontalFlipTextureCoordinates;
        case kGPUImageRotate180: return rotate180TextureCoordinates;
    }
}

#pragma mark -
#pragma mark GPUInput protocol

- (void)newFrameReadyAtTime:(CMTime)frameTime atIndex:(NSInteger)textureIndex;
{
    runSynchronouslyOnVideoProcessingQueue(^{
        [GPUImageContext setActiveShaderProgram:displayProgram];
        [self setDisplayFramebuffer];
        
        glClearColor(backgroundColorRed, backgroundColorGreen, backgroundColorBlue, backgroundColorAlpha);
        glClear(GL_COLOR_BUFFER_BIT);
        
        // Re-render onscreen, flipped to a normal orientation
        glBindFramebuffer(GL_FRAMEBUFFER, 0);
        glBindRenderbuffer(GL_RENDERBUFFER, 0);

        glActiveTexture(GL_TEXTURE4);
        glBindTexture(GL_TEXTURE_2D, [inputFramebufferForDisplay texture]);
        glUniform1i(displayInputTextureUniform, 4);

        glVertexAttribPointer(displayPositionAttribute, 2, GL_FLOAT, 0, 0, imageVertices);
        glVertexAttribPointer(displayTextureCoordinateAttribute, 2, GL_FLOAT, 0, 0, [GPUImageView textureCoordinatesForRotation:inputRotation]);

        BOOL canLockFocus = YES;
        if ([self respondsToSelector:@selector(lockFocusIfCanDraw)])
        {
            canLockFocus = [self lockFocusIfCanDraw];
        }
        else
        {
            [self lockFocus];
        }
        
        if (canLockFocus)
        {
            glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
            
            [self presentFramebuffer];
            glBindTexture(GL_TEXTURE_2D, 0);
            [self unlockFocus];
        }
        
        [inputFramebufferForDisplay unlock];
        inputFramebufferForDisplay = nil;
    });
}

- (NSInteger)nextAvailableTextureIndex;
{
    return 0;
}

- (void)setInputFramebuffer:(GPUImageFramebuffer *)newInputFramebuffer atIndex:(NSInteger)textureIndex;
{
    inputFramebufferForDisplay = newInputFramebuffer;
    [inputFramebufferForDisplay lock];
}

- (void)setInputRotation:(GPUImageRotationMode)newInputRotation atIndex:(NSInteger)textureIndex;
{
    inputRotation = newInputRotation;
}

- (void)setInputSize:(CGSize)newSize atIndex:(NSInteger)textureIndex;
{
    if ((newSize.width < 1.0) || (newSize.height < 1.0))
    {
        return;
    }
    
    runSynchronouslyOnVideoProcessingQueue(^{
        CGSize rotatedSize = newSize;
        
        if (GPUImageRotationSwapsWidthAndHeight(inputRotation))
        {
            rotatedSize.width = newSize.height;
            rotatedSize.height = newSize.width;
        }
        
        if (!CGSizeEqualToSize(inputImageSize, rotatedSize))
        {
            inputImageSize = rotatedSize;
            [self recalculateViewGeometry];
        }
    });
}

- (CGSize)maximumOutputSize;
{
    if ([self respondsToSelector:@selector(convertSizeToBacking:)])
    {
        return [self convertSizeToBacking:self.bounds.size];
    }
    else
    {
        return self.bounds.size;
    }
}

- (void)endProcessing
{
}

- (BOOL)shouldIgnoreUpdatesToThisTarget;
{
    return NO;
}

- (void)conserveMemoryForNextFrame;
{
    
}

- (BOOL)wantsMonochromeInput;
{
    return NO;
}

- (void)setCurrentlyReceivingMonochromeInput:(BOOL)newValue;
{
    
}

#pragma mark -
#pragma mark Accessors

- (CGSize)sizeInPixels;
{
    if (CGSizeEqualToSize(_sizeInPixels, CGSizeZero))
    {
        return [self maximumOutputSize];
    }
    else
    {
        return _sizeInPixels;
    }
}

- (void)setFillMode:(GPUImageFillModeType)newValue;
{
    _fillMode = newValue;
    [self recalculateViewGeometry];
}

@end
