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

//

//  File: OpenGLDrawElements.m

//

//  Abstract: Utility class to deserialize a property list that describes

//            a VBO draw elements parameters and draws an object using

//            the parameters values (cached in an array).

//           

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

//  Computer, Inc. ("Apple") in consideration of your agreement to the

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

//  redistribution of this Apple software constitutes acceptance of these

//  terms.  If you do not agree with these terms, please do not use,

//  install, modify or redistribute this Apple software.

//  

//  In consideration of your agreement to abide by the following terms, and

//  subject to these terms, Apple grants you a personal, non-exclusive

//  license, under Apple's copyrights in this original Apple software (the

//  "Apple Software"), to use, reproduce, modify and redistribute the Apple

//  Software, with or without modifications, in source and/or binary forms;

//  provided that if you redistribute the Apple Software in its entirety and

//  without modifications, you must retain this notice and the following

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

//  Neither the name, trademarks, service marks or logos of Apple Computer,

//  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

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

//  OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.

//  

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

//  OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

//  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

//  INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,

//  MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED

//  AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),

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

//  POSSIBILITY OF SUCH DAMAGE.

// 

//  Copyright (c) 2009 Apple Inc., All rights reserved.

//

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

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

#import "OpenGLDrawElements.h"

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

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

#pragma mark -

#pragma mark Private - Macros

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

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

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

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

#pragma mark -

#pragma mark Private - Data Structures

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

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

struct OpenGLDEParams

{

    GLenum    mode;

    GLsizei   count;

    GLenum    type;

    GLushort  offset;

};

typedef struct OpenGLDEParams   OpenGLDEParams;

typedef struct OpenGLDEParams  *OpenGLDEParamsRef;

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

struct OpenGLDrawElementsData

{

    GLsizeiptr         count;

    GLsizeiptr         size;

    OpenGLDEParamsRef  params;

};

typedef struct OpenGLDrawElementsData  OpenGLDrawElementsData;

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

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

@implementation OpenGLDrawElements

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

- (id) init

{

    self = [super init];

    if( self )

    {

        mpDrawElements = (OpenGLDrawElementsDataRef)calloc(1, sizeof(OpenGLDrawElementsData));

        if( mpDrawElements != NULL )

        {

            mpDrawElements->count  = 0;

            mpDrawElements->size   = 0;

            mpDrawElements->params = NULL; 

        } // if

    } // if

    return( self );

} // init

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

- (void) dealloc

{

    if( mpDrawElements != NULL )

    {

        if( mpDrawElements->params != NULL )

        {

            free( mpDrawElements->params );

        } // if

        free( mpDrawElements );

        mpDrawElements = NULL;

    } // if

    [super dealloc];

} // dealloc

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

- (void) setDictionary:(NSDictionary *)theDictionary

{

    if( theDictionary )

    {

        if( mpDrawElements->params != NULL )

        {

            free( mpDrawElements->params );

            mpDrawElements->count  = 0;

            mpDrawElements->size   = 0;

            mpDrawElements->params = NULL;

        } // if

        NSDictionary *elements = [theDictionary objectForKey:@"Parameters"];

        if( elements )

        {

            NSNumber *count = [elements objectForKey:@"Rows"]; 

            if( count )

            {

                mpDrawElements->count  = [count integerValue];

                mpDrawElements->size   = mpDrawElements->count * sizeof(OpenGLDEParams);

                mpDrawElements->params = (OpenGLDEParamsRef)calloc(1, mpDrawElements->size); 

                if( mpDrawElements->params != NULL )

                {

                    NSArray *table = [elements objectForKey:@"Table"];

                    if( table )

                    {

                        NSArray *element;

                        GLuint i = 0;

                        for( element in table )

                        {

                            mpDrawElements->params[i].mode   = [[element objectAtIndex:0] intValue];

                            mpDrawElements->params[i].count  = [[element objectAtIndex:1] intValue];

                            mpDrawElements->params[i].type   = [[element objectAtIndex:2] intValue];

                            mpDrawElements->params[i].offset = [[element objectAtIndex:3] intValue];

                            i++;

                        } // for

                    } // if

                } // if

            } // if

        } // if

    } // if

} // setDictionary

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

- (void) drawElements

{

    glEnableClientState(GL_NORMAL_ARRAY);

    glEnableClientState(GL_VERTEX_ARRAY);

    {

        GLuint i;

        for( i = 0; i < mpDrawElements->count; i++ )

        {

            glDrawElements(mpDrawElements->params[i].mode,

                           mpDrawElements->params[i].count,

                           mpDrawElements->params[i].type,

                           BUFFER_OFFSET(mpDrawElements->params[i].offset));

        } // for

    }

    glDisableClientState(GL_VERTEX_ARRAY);

    glDisableClientState(GL_NORMAL_ARRAY);

} // drawElements

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

@end

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

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