//---------------------------------------------------------------------------

//

//  File: CVGLTexture.m

//

//  Abstract: Utility class for managing FBOs using CoreVideo opaque

//            texture references.  The CoreVideo textures are vertically 

//            reflected in our FBO, and the texture ready for display and

//            with proper aspect is returned as a result of render to 

//            texture.

//           

//  Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple

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//  following terms, and your use, installation, modification or

//  redistribution of this Apple software constitutes acceptance of these

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//  install, modify or redistribute this Apple software.

//  

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//  text and disclaimers in all such redistributions of the Apple Software. 

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//  Inc. may be used to endorse or promote products derived from the Apple

//  Software without specific prior written permission from Apple.  Except

//  as expressly stated in this notice, no other rights or licenses, express

//  or implied, are granted by Apple herein, including but not limited to

//  any patent rights that may be infringed by your derivative works or by

//  other works in which the Apple Software may be incorporated.

//  

//  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

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//  STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE

//  POSSIBILITY OF SUCH DAMAGE.

// 

//  Copyright (c) 2011 Apple Inc., All rights reserved.

//

//---------------------------------------------------------------------------

//---------------------------------------------------------------------------

#import "OpenGLQuad.h"

#import "CVGLFramebuffer.h"

//---------------------------------------------------------------------------

//---------------------------------------------------------------------------

#pragma mark -

#pragma mark Private - Data Structure

//---------------------------------------------------------------------------

struct CVGLFramebufferData

{

    NSSize              size;

    CVOpenGLTextureRef  image;

    OpenGLQuad         *quads[2];

};

typedef struct CVGLFramebufferData  CVGLFramebufferData;

//---------------------------------------------------------------------------

//---------------------------------------------------------------------------

#pragma mark -

#pragma mark Private - Constructors

//---------------------------------------------------------------------------

static void  CVGLFramebufferUpdateArrayAtIndex(const BOOL isVR,

                                               const GLuint idx,

                                               const NSSize *pSize,

                                               CVGLFramebufferDataRef pFramebuffer)                                           

{    

    GLfloat texCoords[8];

    GLfloat vertices[8];

    texCoords[0] = 0.0f;

    texCoords[1] = 0.0f;

    texCoords[2] = 0.0f;

    texCoords[3] = pSize->height;

    texCoords[4] = pSize->width;

    texCoords[5] = pSize->height;

    texCoords[6] = pSize->width;

    texCoords[7] = 0.0f;

    if( isVR )

    {

        vertices[0] = 0.0f;

        vertices[1] = pSize->height;

        vertices[2] = 0.0f;

        vertices[3] = 0.0f;

        vertices[4] = pSize->width;

        vertices[5] = 0.0f;

        vertices[6] = pSize->width;

        vertices[7] = pSize->height;

    } // if

    else

    {

        vertices[0] = 0.0f;

        vertices[1] = 0.0f;

        vertices[2] = 0.0f;

        vertices[3] = pSize->height;

        vertices[4] = pSize->width;

        vertices[5] = pSize->height;

        vertices[6] = pSize->width;

        vertices[7] = 0.0f;

    } // else

    [pFramebuffer->quads[idx] setTexCoords:texCoords];

    [pFramebuffer->quads[idx] setVertices:vertices];

} // CVGLFramebufferUpdateArrayAtIndex

//---------------------------------------------------------------------------

static void CVGLFramebufferCreateQuadAtIndex(const BOOL isVR,

                                             const GLuint idx,

                                             const NSSize *pSize,

                                             CVGLFramebufferDataRef pFramebuffer)

{

    pFramebuffer->quads[idx] = [[OpenGLQuad alloc] initQuadWithSize:pSize 

                                                             target:GL_TEXTURE_RECTANGLE_ARB];

    if( pFramebuffer->quads[idx] )

    {

        CVGLFramebufferUpdateArrayAtIndex(isVR, idx, pSize, pFramebuffer);

        [pFramebuffer->quads[idx] acquire];

    } // if

} // CVGLFramebufferCreateQuadAtIndex

//---------------------------------------------------------------------------

static void CVGLFramebufferCreateQuateWithSize(const NSSize *pSize,

                                               CVGLFramebufferDataRef pFramebuffer)

{

    pFramebuffer->size.width  = pSize->width;

    pFramebuffer->size.height = pSize->height;

    // A Quad, when using CoreVideo clean texture coordinates

    CVGLFramebufferCreateQuadAtIndex(NO, 0, pSize, pFramebuffer);

    CVGLFramebufferCreateQuadAtIndex(YES, 1, pSize, pFramebuffer);

} // newOpenGLQuads

//---------------------------------------------------------------------------

static CVGLFramebufferDataRef CVGLFramebufferCreateWithSize(const NSSize *pSize)

{

    CVGLFramebufferDataRef pFramebuffer = (CVGLFramebufferDataRef)calloc(1, sizeof(CVGLFramebufferData));

    if( pFramebuffer != NULL )

    {

        CVGLFramebufferCreateQuateWithSize(pSize, pFramebuffer);

    } // if

    else

    {

        NSLog( @">> ERROR: CV GL Framebuffer - Failed allocating memory for the framebuffer backing store!" );

    } // else

    return( pFramebuffer );

} // CVGLFramebufferCreateWithSize

//---------------------------------------------------------------------------

//---------------------------------------------------------------------------

#pragma mark -

#pragma mark Private - Destructors

//---------------------------------------------------------------------------

static void CVGLFramebufferDeleteQuads(CVGLFramebufferDataRef pFramebuffer)

{

    if( pFramebuffer->quads[0] )

    {

        [pFramebuffer->quads[0] release];

    } // if

    if( pFramebuffer->quads[1] )

    {

        [pFramebuffer->quads[1] release];

    } // if

} // CVGLFramebufferDeleteQuads

//---------------------------------------------------------------------------

static void CVGLFramebufferDeleteTexture(CVGLFramebufferDataRef pFramebuffer)

{

    if( pFramebuffer->image != NULL )

    {

        CVOpenGLTextureRelease( pFramebuffer->image );

        pFramebuffer->image = NULL;

    } // if

} // CVGLFramebufferDeleteTexture

//---------------------------------------------------------------------------

static void CVGLFramebufferDeleteAssets(CVGLFramebufferDataRef pFramebuffer)

{

    CVGLFramebufferDeleteQuads(pFramebuffer);

    CVGLFramebufferDeleteTexture(pFramebuffer);

} // CVGLFramebufferDeleteAssets

//---------------------------------------------------------------------------

static void CVGLFramebufferDelete(CVGLFramebufferDataRef pFramebuffer)

{    

    if( pFramebuffer != NULL )

    {

        CVGLFramebufferDeleteAssets(pFramebuffer);

        free( pFramebuffer );

        pFramebuffer = NULL;

    } // if

} // CVGLFramebufferDelete

//---------------------------------------------------------------------------

//---------------------------------------------------------------------------

#pragma mark -

#pragma mark Private - Utilities

//---------------------------------------------------------------------------

static void CVGLFramebufferRender(CVGLFramebufferDataRef pFramebuffer)

{

    // get the texture target

    GLenum target = CVOpenGLTextureGetTarget(pFramebuffer->image);

    // get the texture target name

    GLint name = CVOpenGLTextureGetName(pFramebuffer->image);

    if( name )

    {

        // bind to the CoreVideo texture

        glBindTexture( target, name );

        // draw the quad

        NSUInteger quadIndex = CVOpenGLTextureIsFlipped(pFramebuffer->image);

        // If flipped, then use the vertical-reflect quad

        [pFramebuffer->quads[quadIndex] display];

        // Unbind the CoreVideo texture

        glBindTexture( target, 0 );

    } // if

} // CVGLFramebufferRender

//---------------------------------------------------------------------------

static void CVGLFramebufferSetImage(CVImageBufferRef pImageBuffer,

                                    CVGLFramebufferDataRef pFramebuffer)

{

    CVOpenGLTextureRelease( pFramebuffer->image );

    CVOpenGLTextureRetain( pImageBuffer );

    pFramebuffer->image = pImageBuffer;

} // CVGLFramebufferSetImage

//---------------------------------------------------------------------------

//---------------------------------------------------------------------------

#pragma mark -

//---------------------------------------------------------------------------

@implementation CVGLFramebuffer

//---------------------------------------------------------------------------

//---------------------------------------------------------------------------

#pragma mark -

#pragma mark Public - Designated Initializer

//---------------------------------------------------------------------------

//

// Initialize on startup

//

//---------------------------------------------------------------------------

- (id) initFramebufferWithSize:(const NSSize *)theSize

{

    self = [super initFramebuffer2DWithSize:theSize

                                     target:GL_TEXTURE_RECTANGLE_ARB

                                     format:GL_BGRA

                                      level:0];

    if( self )

    {

        mpFramebuffer = CVGLFramebufferCreateWithSize(theSize);

    } // if

    return  self;

} // initFramebufferWithSize

//---------------------------------------------------------------------------

//---------------------------------------------------------------------------

#pragma mark -

#pragma mark Public - Destructor

//---------------------------------------------------------------------------

- (void) dealloc 

{

    CVGLFramebufferDelete(mpFramebuffer);

    [super dealloc];

} // dealloc

//---------------------------------------------------------------------------

//---------------------------------------------------------------------------

#pragma mark -

#pragma mark Public - Render to texture

//---------------------------------------------------------------------------

//

// Render to texture the video frame provided by Core Video.

//

//---------------------------------------------------------------------------

- (void) update:(CVImageBufferRef)theImageBuffer;

{

    CVGLFramebufferSetImage(theImageBuffer, mpFramebuffer);

    [self enable];

    {

        CVGLFramebufferRender(mpFramebuffer);

    }

    [self disable];

} // update

//---------------------------------------------------------------------------

//---------------------------------------------------------------------------

@end

//---------------------------------------------------------------------------

//---------------------------------------------------------------------------