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GLImagePlugIn.m

/*

        File: GLImagePlugIn.m

    Abstract: GLImagePlugin and GLImage classes.

     Version: 1.0

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    The Apple Software is provided by Apple on an "AS IS" basis.  APPLE

    MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION

    THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS

    FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND

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    IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL

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*/

/* It's highly recommended to use CGL macros instead of changing the current context for plug-ins that perform OpenGL rendering */

#import <OpenGL/CGLMacro.h>

#import "GLImagePlugIn.h"

#define kQCPlugIn_Name              @"OpenGL Image"

#define kQCPlugIn_Description       @"Produces an image of a given size containing a diagonal color gradient."

#if !__USE_PROVIDER__

static void _TextureReleaseCallback(CGLContextObj cgl_ctx, GLuint name, void* info)

    glDeleteTextures(1, &name);

#endif

/* Generates a texture containing a linear gradient - Requires FBO support */

static GLuint _CreateTexture(CGLContextObj cgl_ctx, NSUInteger pixelsWide, NSUInteger pixelsHigh, const CGFloat topColor[4], const CGFloat bottomColor[4], NSRect bounds)

    GLsizei                         width = bounds.size.width,

                                    height = bounds.size.height;

    GLuint                          name,

                                    frameBuffer;

    GLint                           saveName,

                                    saveViewport[4],

                                    saveMode;

    GLenum                          status;

    /* Create texture to render into */

    glGenTextures(1, &name);

    glGetIntegerv(GL_TEXTURE_BINDING_RECTANGLE_EXT, &saveName);

    glBindTexture(GL_TEXTURE_RECTANGLE_EXT, name);

    glTexImage2D(GL_TEXTURE_RECTANGLE_EXT, 0, GL_RGBA8, width, height, 0, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, NULL);

    glBindTexture(GL_TEXTURE_RECTANGLE_EXT, saveName);

    /* Create temporary FBO to render in texture */

    glGenFramebuffersEXT(1, &frameBuffer);

    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, frameBuffer);

    glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_RECTANGLE_EXT, name, 0);

    status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);

    if(status == GL_FRAMEBUFFER_COMPLETE_EXT) {

        /* Setup OpenGL states */

        glGetIntegerv(GL_VIEWPORT, saveViewport);

        glViewport(0, 0, width, height);

        glGetIntegerv(GL_MATRIX_MODE, &saveMode);

        glMatrixMode(GL_PROJECTION);

        glPushMatrix();

        glLoadIdentity();

        glOrtho(bounds.origin.x, bounds.origin.x + bounds.size.width, bounds.origin.y, bounds.origin.y + bounds.size.height, -1, 1);

        glMatrixMode(GL_MODELVIEW);

        glPushMatrix();

        glLoadIdentity();

        /* Render gradient quad */

        glBegin(GL_QUADS);

            /* Set current color (no need to save / restore as the current color is part of the GL_CURRENT_BIT) */

            glColor4f(topColor[0], topColor[1], topColor[2], topColor[3]);

            /* Draw top vertices */

            glVertex2f(pixelsWide, pixelsHigh);

            glVertex2f(0, pixelsHigh);

            /* Set current color (no need to save / restore as the current color is part of the GL_CURRENT_BIT) */

            glColor4f(bottomColor[0], bottomColor[1], bottomColor[2], bottomColor[3]);

            /* Draw bottom vertices */

            glVertex2f(0, 0);

            glVertex2f(pixelsWide, 0);

        glEnd();

        /* Restore OpenGL states */

        glMatrixMode(GL_MODELVIEW);

        glPopMatrix();

        glMatrixMode(GL_PROJECTION);

        glPopMatrix();

        glMatrixMode(saveMode);

        glViewport(saveViewport[0], saveViewport[1], saveViewport[2], saveViewport[3]);

    else {

        glDeleteTextures(1, &name);

        name = 0;

    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

    glDeleteFramebuffersEXT(1, &frameBuffer);

    /* Check for OpenGL errors */

    status = glGetError();

    if(status) {

        NSLog(@"OpenGL error %04X", status);

        glDeleteTextures(1, &name);

        name = 0;

    return name;

@implementation GLImagePlugIn

/* We need to declare the input / output properties as dynamic as Quartz Composer will handle their implementation */

@dynamic inputWidth, inputHeight, inputStartColor, inputEndColor, outputGradientImage;

+ (NSDictionary*) attributes

    /* Return the attributes of this plug-in */

    return [NSDictionary dictionaryWithObjectsAndKeys:kQCPlugIn_Name, QCPlugInAttributeNameKey, kQCPlugIn_Description, QCPlugInAttributeDescriptionKey, nil];

+ (NSDictionary*) attributesForPropertyPortWithKey:(NSString*)key

    /* Return the attributes for the plug-in property ports */

    if([key isEqualToString:@"inputWidth"])

    return [NSDictionary dictionaryWithObjectsAndKeys:@"Image Pixels Width", QCPortAttributeNameKey, [NSNumber numberWithUnsignedInteger:1024], QCPortAttributeMaximumValueKey, [NSNumber numberWithUnsignedInteger:256], QCPortAttributeDefaultValueKey, nil];

    if([key isEqualToString:@"inputHeight"])

    return [NSDictionary dictionaryWithObjectsAndKeys:@"Image Pixels Height", QCPortAttributeNameKey, [NSNumber numberWithUnsignedInteger:1024], QCPortAttributeMaximumValueKey, [NSNumber numberWithUnsignedInteger:256], QCPortAttributeDefaultValueKey, nil];

    if([key isEqualToString:@"inputStartColor"])

    return [NSDictionary dictionaryWithObjectsAndKeys:@"Top Color", QCPortAttributeNameKey, [(id)CGColorCreateGenericRGB(1.0, 0.0, 0.0, 1.0) autorelease], QCPortAttributeDefaultValueKey, nil];

    if([key isEqualToString:@"inputEndColor"])

    return [NSDictionary dictionaryWithObjectsAndKeys:@"Bottom Color", QCPortAttributeNameKey, [(id)CGColorCreateGenericRGB(0.0, 0.0, 1.0, 1.0) autorelease], QCPortAttributeDefaultValueKey, nil];

    if([key isEqualToString:@"outputGradientImage"])

    return [NSDictionary dictionaryWithObjectsAndKeys:@"Gradient Image", QCPortAttributeNameKey, nil];

    return nil;

+ (QCPlugInExecutionMode) executionMode

    /* This plug-in is a processor */

    return kQCPlugInExecutionModeProcessor;

+ (QCPlugInTimeMode) timeMode

    /* This plug-in does not depend on the time (time parameter is completely ignored in the -execute:atTime:withArguments: method) */

    return kQCPlugInTimeModeNone;

@end

@implementation GLImagePlugIn (Execution)

#if __USE_PROVIDER__

- (BOOL) execute:(id<QCPlugInContext>)context atTime:(NSTimeInterval)time withArguments:(NSDictionary*)arguments

    GLImage*                        gradientImage = nil;

    /* If we have valid dimensions, create a result image object */

    if((self.inputWidth > 0) && (self.inputHeight > 0)) {

        gradientImage = [[GLImage alloc] initWithColorSpace:[context colorSpace] pixelsWide:self.inputWidth pixelsHigh:self.inputHeight topColor:self.inputStartColor bottomColor:self.inputEndColor];

        if(gradientImage == nil)

        return NO;

        self.outputGradientImage = gradientImage;

        [gradientImage release];

    /* otherwise, don't produce any result image */

    else

    self.outputGradientImage = nil;

    return YES;

#else

- (BOOL) execute:(id<QCPlugInContext>)context atTime:(NSTimeInterval)time withArguments:(NSDictionary*)arguments

    CGLContextObj                   cgl_ctx = [context CGLContextObj];

    id                              provider;

    GLuint                          name;

    /* If we have valid dimensions, create a result image object */

    if((self.inputWidth > 0) && (self.inputHeight > 0)) {

        /* Create texture */

        name = _CreateTexture(cgl_ctx, self.inputWidth, self.inputHeight, CGColorGetComponents(self.inputStartColor), CGColorGetComponents(self.inputEndColor), NSMakeRect(0, 0, self.inputWidth, self.inputHeight));

        if(name == 0)

        return NO;

        /* Make sure to flush as we use FBOs and the passed OpenGL context may not have a surface attached */

        glFlushRenderAPPLE();

        /* Create output image provider */

#if __BIG_ENDIAN__

        provider = [context outputImageProviderFromTextureWithPixelFormat:QCPlugInPixelFormatARGB8 pixelsWide:self.inputWidth pixelsHigh:self.inputHeight name:name flipped:NO releaseCallback:_TextureReleaseCallback releaseContext:NULL colorSpace:[context colorSpace] shouldColorMatch:YES];

#else

        provider = [context outputImageProviderFromTextureWithPixelFormat:QCPlugInPixelFormatBGRA8 pixelsWide:self.inputWidth pixelsHigh:self.inputHeight name:name flipped:NO releaseCallback:_TextureReleaseCallback releaseContext:NULL colorSpace:[context colorSpace] shouldColorMatch:YES];

#endif

        if(provider == nil) {

            glDeleteTextures(1, &name);

            return NO;

    /* otherwise, don't produce any result image */

    else

    provider = nil;

    self.outputGradientImage = provider;

    return YES;

#endif

@end

#if __USE_PROVIDER__

@implementation GLImage

- (id) initWithColorSpace:(CGColorSpaceRef)colorSpace pixelsWide:(NSUInteger)width pixelsHigh:(NSUInteger)height topColor:(CGColorRef)topColor bottomColor:(CGColorRef)bottomColor

    const CGFloat*              components;

    /* Make sure we have valid parameters */

    if(!colorSpace || !width || !height || !topColor || !bottomColor) {

        [self release];

        return nil;

    /* Keep the parameters around */

    if(self = [super init]) {

        _colorSpace = CGColorSpaceRetain(colorSpace);

        _width = width;

        _height = height;

        components = CGColorGetComponents(topColor); //This CGColorRef is guaranteed to be of type RGBA

        _topColor[0] = components[0];

        _topColor[1] = components[1];

        _topColor[2] = components[2];

        _topColor[3] = components[3];

        components = CGColorGetComponents(bottomColor); //This CGColorRef is guaranteed to be of type RGBA

        _bottomColor[0] = components[0];

        _bottomColor[1] = components[1];

        _bottomColor[2] = components[2];

        _bottomColor[3] = components[3];

    return self;

- (void) dealloc

    CGColorSpaceRelease(_colorSpace);

    [super dealloc];

- (NSRect) imageBounds

    /* Compute bounds from width and height */

    return NSMakeRect(0, 0, _width, _height);

- (CGColorSpaceRef) imageColorSpace

    /* We render in our initial colorspace */

    return _colorSpace;

#if __USE_RENDERED_TEXTURES__

- (NSArray*) supportedRenderedTexturePixelFormats

#if __BIG_ENDIAN__

    return [NSArray arrayWithObject:QCPlugInPixelFormatARGB8];

#else

    return [NSArray arrayWithObject:QCPlugInPixelFormatBGRA8];

#endif

- (GLuint) copyRenderedTextureForCGLContext:(CGLContextObj)cgl_ctx pixelFormat:(NSString*)format bounds:(NSRect)bounds isFlipped:(BOOL*)flipped

    return _CreateTexture(cgl_ctx, _width, _height, _topColor, _bottomColor, bounds);

- (void) releaseRenderedTexture:(GLuint)name forCGLContext:(CGLContextObj)cgl_ctx

    glDeleteTextures(1, &name);

#else

- (BOOL) canRenderWithCGLContext:(CGLContextObj)cgl_ctx

    /* This image provider can render using any OpenGL context */

    return YES;

- (BOOL) renderWithCGLContext:(CGLContextObj)cgl_ctx forBounds:(NSRect)bounds

    GLint                           saveMode;

    /* Set projection matrix to the image bounds (the viewport is already set and the projection and modelview matrices are identity) */

    glGetIntegerv(GL_MATRIX_MODE, &saveMode);

    glMatrixMode(GL_PROJECTION);

    glPushMatrix();

    glOrtho(bounds.origin.x, bounds.origin.x + bounds.size.width, bounds.origin.y, bounds.origin.y + bounds.size.height, -1, 1);

    /* Render gradient quad */

    glBegin(GL_QUADS);

        /* Set current color (no need to save / restore as the current color is part of the GL_CURRENT_BIT) */

        glColor4f(_topColor[0], _topColor[1], _topColor[2], _topColor[3]);

        /* Draw top vertices */

        glVertex2f(_width, _height);

        glVertex2f(0, _height);

        /* Set current color (no need to save / restore as the current color is part of the GL_CURRENT_BIT) */

        glColor4f(_bottomColor[0], _bottomColor[1], _bottomColor[2], _bottomColor[3]);

        /* Draw bottom vertices */

        glVertex2f(0, 0);

        glVertex2f(_width, 0);

    glEnd();

    /* Restore projection matrix */

    glPopMatrix();

    glMatrixMode(saveMode);

    return YES;

#endif

@end

#endif

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