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

//

//  File: OpenGLNumberUtilities.m

//

//  Abstract: Some common utility methods for OpenGL.

//           

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

#import <OpenGL/glu.h>

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

#import "OpenGLSizes.h"

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

#import "OpenGLUtilities.h"

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

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

#pragma mark -

#pragma mark Private - Constants

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

static const GLubyte *kGLARBTextureNPOT = (const GLubyte *)"GL_ARB_texture_non_power_of_two";

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

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

#pragma mark -

#pragma mark Public - Utilities

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

GLuint OpenGLUtilitiesGetSPP(const GLenum nType)

{

    GLuint nSize = 0;

    switch( nType )

    {

        case GL_BYTE:

            nSize = kOpenGLSizeSignedByte;

            break;

        case GL_UNSIGNED_BYTE:

        case GL_UNSIGNED_BYTE_3_3_2:

        case GL_UNSIGNED_BYTE_2_3_3_REV:

            nSize = kOpenGLSizeUnsignedByte;

            break;

        case GL_SHORT:

            nSize = kOpenGLSizeSignedShort;

            break;

        case GL_UNSIGNED_SHORT:

        case GL_UNSIGNED_SHORT_4_4_4_4:

        case GL_UNSIGNED_SHORT_5_5_5_1:

        case GL_UNSIGNED_SHORT_5_6_5:

        case GL_UNSIGNED_SHORT_5_6_5_REV:

        case GL_UNSIGNED_SHORT_4_4_4_4_REV:

        case GL_UNSIGNED_SHORT_1_5_5_5_REV:

        case GL_UNSIGNED_SHORT_8_8_APPLE:

        case GL_UNSIGNED_SHORT_8_8_REV_APPLE:

            nSize = kOpenGLSizeUnsignedShort;

            break;

        case GL_INT:

            nSize = kOpenGLSizeSignedInt;

            break;

        case GL_HALF_FLOAT:

            nSize = kOpenGLSizeHalfFloat;

            break;

        case GL_FLOAT:

            nSize = kOpenGLSizeFloat;

            break;

        case GL_DOUBLE:

            nSize = kOpenGLSizeDouble;

            break;

        case GL_2_BYTES:

            nSize = kOpenGLSize2Bytes;

            break;

        case GL_3_BYTES:

            nSize = kOpenGLSize3Bytes;

            break;

        case GL_4_BYTES:

            nSize = kOpenGLSize4Bytes;

            break;

        case GL_UNSIGNED_INT:

        case GL_UNSIGNED_INT_8_8_8_8:

        case GL_UNSIGNED_INT_10_10_10_2:

        case GL_UNSIGNED_INT_8_8_8_8_REV:

        case GL_UNSIGNED_INT_2_10_10_10_REV:

        default:

            nSize = kOpenGLSizeUnsignedInt;

            break;

    } // switch

    return( nSize );

} // OpenGLUtilitiesGetSPP

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

GLuint OpenGLUtilitiesGetPOT(GLuint nValue)

{

    --nValue;

    nValue |= (nValue >> 1);

    nValue |= (nValue >> 2);

    nValue |= (nValue >> 4);

    nValue |= (nValue >> 8);

    nValue |= (nValue >> 16);

    ++nValue;

    return( nValue );

} // GetPOT

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

BOOL OpenGLUtilitiesTextureIsNPOT()

{

    const GLubyte *pGLExtString = glGetString(GL_EXTENSIONS);

    BOOL  bGLExtIsFound = gluCheckExtension(kGLARBTextureNPOT, pGLExtString);

    return( bGLExtIsFound );

} // OpenGLUtilitiesTextureIsNPOT

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

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