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

//

//  File: OpenGLVBOQuad.m

//

//  Abstract: Utility toolkit for handling a quad VBO

//           

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//

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

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

#import "OpenGLVBOQuad.h"

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

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

#pragma mark -

#pragma mark Private Data Structures

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

struct OpenGLVBOQuadData

{

    GLuint    name;         // buffer identifier

    GLuint    count;        // vertex count

    GLuint    size;         // size of vertices or texture coordinates

    GLsizei   stride;       // vbo stride

    GLuint    capacity;     // is vertex size + texture coordinate size

    GLenum    target;       // vbo target

    GLenum    usage;        // vbo usage

    GLenum    type;         // vbo type

    GLenum    mode;         // vbo mode

    GLfloat  *data;         // vbo data

    GLfloat   width;        // quad width

    GLfloat   height;       // quad height

};

typedef struct OpenGLVBOQuadData  OpenGLVBOQuadData;

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

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

#define BUFFER_OFFSET(i) ((char *)NULL + (i))

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

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

#pragma mark

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

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

@implementation OpenGLVBOQuad

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

- (void) initVBOQuad:(const NSSize *)theSize

{

    mpVBOQuad->count    = 4;

    mpVBOQuad->size     = 8 * sizeof(GLfloat);

    mpVBOQuad->capacity = 2 * mpVBOQuad->size;

    mpVBOQuad->target   = GL_ARRAY_BUFFER;

    mpVBOQuad->usage    = GL_STATIC_DRAW;

    mpVBOQuad->type     = GL_FLOAT;

    mpVBOQuad->mode     = GL_QUADS;

    mpVBOQuad->stride   = 0;

    mpVBOQuad->data     = NULL;

    mpVBOQuad->width    = theSize->width;

    mpVBOQuad->height   = theSize->height;

} // initVBOQuad

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

- (void) newVBOQuad:(const GLfloat *)theVertices

          texCoords:(const GLfloat *)theTexCoords

{

    glGenBuffers(1, &mpVBOQuad->name);

    if( mpVBOQuad->name )

    {

        glBindBuffer(mpVBOQuad->target,

                     mpVBOQuad->name);

        glBufferData(mpVBOQuad->target, mpVBOQuad->capacity, NULL, mpVBOQuad->usage);

        glBufferSubData(mpVBOQuad->target, 0, mpVBOQuad->size, theVertices);

        glBufferSubData(mpVBOQuad->target, mpVBOQuad->size, mpVBOQuad->size, theTexCoords);

        glBindBuffer(mpVBOQuad->target, 0);

    } // if

} // newVBOQuad

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

//

// Initialize

//

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

- (id) init

{

    self = [super init];

    if( self )

    {

        mpVBOQuad = (OpenGLVBOQuadDataRef)calloc(1,sizeof(OpenGLVBOQuadData));

        if( mpVBOQuad != NULL )

        {

            GLfloat data[8] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };

            NSSize  size    = NSMakeSize( 0.0f, 0.0f );

            [self initVBOQuad:&size];

            [self newVBOQuad:data 

                   texCoords:data];         

        } // if

        else

        {

            NSLog( @">> ERROR: OpenGL VBO Quad - Failure Allocating Memory For Attributes!" );

            NSLog( @">>                          From the default initializer." );

        }  // else

    } // if

    return( self );

} // init

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

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

{

    self = [super init];

    if( self )

    {

        mpVBOQuad = (OpenGLVBOQuadDataRef)calloc(1, sizeof(OpenGLVBOQuadData));

        if( mpVBOQuad != NULL )

        {

            if( theSize != NULL )

            {

                GLfloat vertices[8]  = { 0.0f, 0.0f, theSize->width, 0.0f, theSize->width, theSize->height, 0.0f, theSize->height };

                GLfloat texCoords[8] = { 0.0f, theSize->height, theSize->width, theSize->height, theSize->width, 0.0f, 0.0f, 0.0f };

                [self initVBOQuad:theSize];

                [self newVBOQuad:vertices 

                       texCoords:texCoords];        

            } // if

            else

            {

                GLfloat data[8] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };

                NSSize  size    = NSMakeSize( 0.0f, 0.0f );

                [self initVBOQuad:&size];

                [self newVBOQuad:data 

                       texCoords:data];         

            } // else

        } // if

        else

        {

            NSLog( @">> ERROR: OpenGL VBO Quad - Failure Allocating Memory For Attributes!" );

            NSLog( @">>                          From the designated initializer using size." );

        }  // else

    } // if

    return( self );

} // initVBOWithSize

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

#pragma mark -

#pragma mark Delete VBO

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

- (void) cleanUpVBOQuad

{

    if( mpVBOQuad != NULL )

    {

        if( mpVBOQuad->name )

        {

            glDeleteBuffers( 1, &mpVBOQuad->name );

        } // if

        free( mpVBOQuad );

        mpVBOQuad = NULL;

    } // if

} // cleanUpVBOQuad

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

- (void) dealloc 

{

    [self cleanUpVBOQuad];

    [super dealloc];

} // dealloc

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

#pragma mark -

#pragma mark VBO Update

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

- (void) setFrame:(const NSRect *)theFrame

{

    if( theFrame != NULL )

    {

        mpVBOQuad->width  = theFrame->origin.x + theFrame->size.width;

        mpVBOQuad->height = theFrame->origin.y + theFrame->size.height;

        glBindBuffer(mpVBOQuad->target, 

                     mpVBOQuad->name);

        glBufferData(mpVBOQuad->target, 

                     mpVBOQuad->capacity, 

                     NULL,

                     mpVBOQuad->usage);

        mpVBOQuad->data = (GLfloat *)glMapBuffer(mpVBOQuad->target, 

                                                  GL_READ_WRITE);

        if( mpVBOQuad->data != NULL )

        {

            // Vertices

            mpVBOQuad->data[0] = theFrame->origin.x;

            mpVBOQuad->data[1] = theFrame->origin.y;

            mpVBOQuad->data[2] = theFrame->origin.x;

            mpVBOQuad->data[3] = mpVBOQuad->height;

            mpVBOQuad->data[4] = mpVBOQuad->width;

            mpVBOQuad->data[5] = mpVBOQuad->height,

            mpVBOQuad->data[6] = mpVBOQuad->width;

            mpVBOQuad->data[7] = theFrame->origin.y;

            // Texture coordinates

            mpVBOQuad->data[8]  = 0.0f;

            mpVBOQuad->data[9]  = 0.0f;

            mpVBOQuad->data[10] = 0.0f;

            mpVBOQuad->data[11] = theFrame->size.height;

            mpVBOQuad->data[12] = theFrame->size.width;

            mpVBOQuad->data[13] = theFrame->size.height,

            mpVBOQuad->data[14] = theFrame->size.width;

            mpVBOQuad->data[15] = 0.0f;

            glUnmapBuffer(mpVBOQuad->target);

        } // if

        glBindBuffer(mpVBOQuad->target, 0);

    } // if

} // setFrame

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

- (void) setSize:(const NSSize *)theSize

{

    if( theSize != NULL )

    {

        GLfloat vertices[8]  = { 0.0f, 0.0f, theSize->width, 0.0f, theSize->width, theSize->height, 0.0f, theSize->height };

        GLfloat texCoords[8] = { 0.0f, theSize->height, theSize->width, theSize->height, theSize->width, 0.0f, 0.0f, 0.0f };

        mpVBOQuad->width  = theSize->width;

        mpVBOQuad->height = theSize->height;

        glBindBuffer(mpVBOQuad->target, 

                     mpVBOQuad->name);

        glBufferData(mpVBOQuad->target, 

                     mpVBOQuad->capacity, 

                     NULL, 

                     mpVBOQuad->usage);

        mpVBOQuad->data = (GLfloat *)glMapBuffer(mpVBOQuad->target, 

                                                  GL_READ_WRITE);

        if( mpVBOQuad->data != NULL )

        {

            // Vertices

            mpVBOQuad->data[0] = vertices[0];

            mpVBOQuad->data[1] = vertices[1];

            mpVBOQuad->data[2] = vertices[2];

            mpVBOQuad->data[3] = vertices[3];

            mpVBOQuad->data[4] = vertices[4];

            mpVBOQuad->data[5] = vertices[5],

            mpVBOQuad->data[6] = vertices[6];

            mpVBOQuad->data[7] = vertices[7];

            // Texture coordinates

            mpVBOQuad->data[8]  = texCoords[0];

            mpVBOQuad->data[9]  = texCoords[1];

            mpVBOQuad->data[10] = texCoords[2];

            mpVBOQuad->data[11] = texCoords[3];

            mpVBOQuad->data[12] = texCoords[4];

            mpVBOQuad->data[13] = texCoords[5],

            mpVBOQuad->data[14] = texCoords[6];

            mpVBOQuad->data[15] = texCoords[7];

            glUnmapBuffer(mpVBOQuad->target);

        } // if

        glBindBuffer(mpVBOQuad->target, 0);

    } // if

} // setSize

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

#pragma mark -

#pragma mark VBO Draw

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

//

// Draw a quad using texture & vertex coordinates

//

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

- (void) bind

{

    glBindBuffer(mpVBOQuad->target, mpVBOQuad->name);

    glEnableClientState(GL_TEXTURE_COORD_ARRAY);

    glEnableClientState(GL_VERTEX_ARRAY);

    glTexCoordPointer(2, mpVBOQuad->type, mpVBOQuad->stride, BUFFER_OFFSET(mpVBOQuad->size));

    glVertexPointer(2, mpVBOQuad->type, mpVBOQuad->stride, BUFFER_OFFSET(0));

    glDrawArrays(mpVBOQuad->mode, 0, mpVBOQuad->count);

    glDisableClientState(GL_VERTEX_ARRAY);

    glDisableClientState(GL_TEXTURE_COORD_ARRAY);

    glBindBuffer(mpVBOQuad->target, 0);

} // bind

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

@end

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

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