/*

        File: PBufferRenderer.m

    Abstract: PBufferRenderer class.

     Version: 1.1

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*/

#import <OpenGL/CGLMacro.h>

#import "PBufferRenderer.h"

@implementation PBufferRenderer

- (id) init

{

    return [self initWithCompositionPath:nil textureTarget:0 textureWidth:0 textureHeight:0 openGLContext:nil];

}

- (id) initWithCompositionPath:(NSString*)path textureTarget:(GLenum)target textureWidth:(unsigned)width textureHeight:(unsigned)height openGLContext:(NSOpenGLContext*)context

{

    //IMPORTANT: We use the macros provided by <OpenGL/CGLMacro.h> which provide better performances and allows us not to bother with making sure the current context is valid

    CGLContextObj                   cgl_ctx = [context CGLContextObj];

    NSOpenGLPixelFormatAttribute    attributes[] = {

                                                        NSOpenGLPFAPixelBuffer,

                                                        NSOpenGLPFANoRecovery,

                                                        NSOpenGLPFAAccelerated,

                                                        NSOpenGLPFADepthSize, 24,

                                                        (NSOpenGLPixelFormatAttribute) 0

                                                    };

    NSOpenGLPixelFormat*            format = [[[NSOpenGLPixelFormat alloc] initWithAttributes:attributes] autorelease];

    GLint                           saveTextureName;

    //Check parameters - Rendering at sizes smaller than 16x16 will likely produce garbage and we only support 2D or RECT textures

    if(![path length] || ((target != GL_TEXTURE_2D) && (target != GL_TEXTURE_RECTANGLE_EXT)) || (width < 16) || (height < 16) || (context == nil)) {

        [self release];

        return nil;

    }

    if(self = [super init]) {

        //Keep the target OpenGL context around

        _textureContext = [context retain];

        //Create the OpenGL pBuffer to render into

        _pixelBuffer = [[NSOpenGLPixelBuffer alloc] initWithTextureTarget:target textureInternalFormat:GL_RGBA textureMaxMipMapLevel:0 pixelsWide:width pixelsHigh:height];

        if(_pixelBuffer == nil) {

            NSLog(@"Cannot create OpenGL pixel buffer");

            [self release];

            return nil;

        }

        //Create the OpenGL context to use to render in the pBuffer (with color and depth buffers) - It needs to be shared to ensure both contexts have identical virtual screen lists

        _pixelBufferContext = [[NSOpenGLContext alloc] initWithFormat:format shareContext:_textureContext];

        if(_pixelBufferContext == nil) {

            NSLog(@"Cannot create OpenGL context");

            [self release];

            return nil;

        }

        //Attach the OpenGL context to the pBuffer (make sure it uses the same virtual screen as the primary OpenGL context)

        [_pixelBufferContext setPixelBuffer:_pixelBuffer cubeMapFace:0 mipMapLevel:0 currentVirtualScreen:[_textureContext currentVirtualScreen]];

        //Create the QuartzComposer Renderer with that OpenGL context and the specified composition file

        _renderer = [[QCRenderer alloc] initWithOpenGLContext:_pixelBufferContext pixelFormat:format file:path];

        if(_renderer == nil) {

            NSLog(@"Cannot create QCRenderer");

            [self release];

            return nil;

        }

        //Create the texture on the target OpenGL context

        _textureTarget = target;

        glGenTextures(1, &_textureName);

        //Configure the texture - For extra safety, we save and restore the currently bound texture

        glGetIntegerv((_textureTarget == GL_TEXTURE_RECTANGLE_EXT ? GL_TEXTURE_BINDING_RECTANGLE_EXT : GL_TEXTURE_BINDING_2D), &saveTextureName);

        glBindTexture(_textureTarget, _textureName);

        glTexParameteri(_textureTarget, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

        glTexParameteri(_textureTarget, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

        if(_textureTarget == GL_TEXTURE_RECTANGLE_EXT) {

            glTexParameteri(_textureTarget, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);

            glTexParameteri(_textureTarget, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

        }

        else {

            glTexParameteri(_textureTarget, GL_TEXTURE_WRAP_S, GL_REPEAT);

            glTexParameteri(_textureTarget, GL_TEXTURE_WRAP_T, GL_REPEAT);

        }

        glBindTexture(_textureTarget, saveTextureName);

        //Update the texture immediately

        [self updateTextureForTime:0.0];

    }

    return self;

}

- (void) _updateTextureOnTargetContext

{

    //IMPORTANT: We use the macros provided by <OpenGL/CGLMacro.h> which provide better performances and allows us not to bother with making sure the current context is valid

    CGLContextObj                   cgl_ctx = [_textureContext CGLContextObj];

    GLint                           saveTextureName;

    //Save the currently bound texture

    glGetIntegerv((_textureTarget == GL_TEXTURE_RECTANGLE_EXT ? GL_TEXTURE_BINDING_RECTANGLE_EXT : GL_TEXTURE_BINDING_2D), &saveTextureName);

    //Bind the texture and update its contents

    glBindTexture(_textureTarget, _textureName);

    [_textureContext setTextureImageToPixelBuffer:_pixelBuffer colorBuffer:GL_FRONT];

    //Restore the previously bound texture

    glBindTexture(_textureTarget, saveTextureName);

}

- (BOOL) updateTextureForTime:(NSTimeInterval)time

{

    //IMPORTANT: We use the macros provided by <OpenGL/CGLMacro.h> which provide better performances and allows us not to bother with making sure the current context is valid

    CGLContextObj                   cgl_ctx = [_pixelBufferContext CGLContextObj];

    BOOL                            success;

    GLenum                          error;

    NSOpenGLPixelBuffer*            pBuffer;

    //Make sure the virtual screen for the pBuffer and its rendering context match the target one

    if([_textureContext currentVirtualScreen] != [_pixelBufferContext currentVirtualScreen]) {

        pBuffer = [[NSOpenGLPixelBuffer alloc] initWithTextureTarget:_textureTarget textureInternalFormat:GL_RGBA textureMaxMipMapLevel:0 pixelsWide:[_pixelBuffer pixelsWide] pixelsHigh:[_pixelBuffer pixelsHigh]];

        if(pBuffer) {

            [_pixelBufferContext clearDrawable];

            [_pixelBuffer release];

            _pixelBuffer = pBuffer;

            [_pixelBufferContext setPixelBuffer:_pixelBuffer cubeMapFace:0 mipMapLevel:0 currentVirtualScreen:[_textureContext currentVirtualScreen]];

        }

        else {

            NSLog(@"%: Failed recreating OpenGL pixel buffer");

            return NO;

        }

    }

    //Render a frame from the composition at the specified time in the pBuffer

    success = [_renderer renderAtTime:time arguments:nil];

    //IMPORTANT: Make sure all OpenGL rendering commands were sent to the pBuffer OpenGL context

    glFlushRenderAPPLE();

    //Update the texture in the target OpenGL context from the contents of the pBuffer

    [self _updateTextureOnTargetContext];

    //Check for errors

    if(error = glGetError())

    NSLog(@"%@: OpenGL error 0x%04X", error);

    return success;

}

- (GLenum) textureTarget

{

    return _textureTarget;

}

- (GLuint) textureName

{

    return _textureName;

}

- (unsigned) textureWidth

{

    return [_pixelBuffer pixelsWide];

}

- (unsigned) textureHeight

{

    return [_pixelBuffer pixelsHigh];

}

- (float) textureCoordSMin

{

    return 0.0;

}

- (float) textureCoordSMax

{

    return (_textureTarget == GL_TEXTURE_RECTANGLE_EXT ? (float)[_pixelBuffer pixelsWide] : 1.0);

}

- (float) textureCoordTMin

{

    return 0.0;

}

- (float) textureCoordTMax

{

    return (_textureTarget == GL_TEXTURE_RECTANGLE_EXT ? (float)[_pixelBuffer pixelsHigh] : 1.0);

}

- (void) dealloc 

{

    //IMPORTANT: We use the macros provided by <OpenGL/CGLMacro.h> which provide better performances and allows us not to bother with making sure the current context is valid

    CGLContextObj                   cgl_ctx = [_textureContext CGLContextObj];

    //Destroy the texture on the target OpenGL context

    if(_textureName)

    glDeleteTextures(1, &_textureName);

    //Destroy the renderer

    [_renderer release];

    //Destroy the OpenGL context

    [_pixelBufferContext clearDrawable];

    [_pixelBufferContext release];

    //Destroy the OpenGL pixel buffer

    [_pixelBuffer release];

    //Release target OpenGL context

    [_textureContext release];

    [super dealloc];

}

@end