//---------------------------------------------------------------------------
//
//	File: OpenGLPlasmaPatternTexture.m
//
//  Abstract: Utility toolkit for handling plasma shader's color pattern
//            by providing a data source to begin with
// 			 
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//
//---------------------------------------------------------------------------

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

#import "OpenGLPlasmaPatternTexture.h"

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

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

@implementation OpenGLPlasmaPatternTexture

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

#pragma mark -
#pragma mark OpenGL Plasma Shader Texture Initializations

//---------------------------------------------------------------------------
//
// Initialize
//
//---------------------------------------------------------------------------

- (id) initPlasmaShaderPatternWithWidth:(const NSInteger)thePatternWidth 
								 height:(const NSInteger)thePatternHeight
{
	self = [super initPatternWithSize:thePatternWidth 
							   height:thePatternHeight 
						activeTexture:GL_TEXTURE0];
	
	if( self )
	{
		patternWidth  = thePatternWidth;
		patternHeight = thePatternHeight;
	} // if
	else
	{
		NSLog( @">> ERROR: OpenGL Plasma Texture Pattern - Failure Allocating Plasma pattern for the requested size!" );
	} // else
	
	return self;
} // initPlasmaShaderPatternWithWidth

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

+ (id) plasmaShaderPatternWithWidth:(const NSInteger)thePatternWidth 
							 height:(const NSInteger)thePatternHeight
{
	return  [[[OpenGLPlasmaPatternTexture allocWithZone:[self zone]] initPlasmaShaderPatternWithWidth:thePatternWidth 
																							 height:thePatternHeight] autorelease];
} // plasmaShaderPatternWithWidth

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

#pragma mark -
#pragma mark Delete Plasma Pattern

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

- (void) dealloc 
{
    [super dealloc];
} // dealloc

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

#pragma mark -
#pragma mark Plasma Pattern Pixels

//---------------------------------------------------------------------------
//
// This is the data source for the plasma pattern.
//
//---------------------------------------------------------------------------

- (GLvoid *) texturePixels:(const NSInteger)theTextureWidth 
					height:(const NSInteger)theTextureHeight 
					 depth:(const NSInteger)theTextureDepth
{
	GLuint    size    = 3 * sizeof(GLfloat) * theTextureWidth * theTextureHeight; 
	GLfloat  *pattern = (GLfloat *)malloc(size);
	
	if( pattern != NULL )
	{
		GLfloat   a = (GLfloat)theTextureWidth;
		GLfloat   b = 1.0f / ( 0.25f * a );
		GLfloat   c = 1.0f / ( 0.125f * a );
		GLfloat   f;
		GLfloat   x;
		GLfloat   y;
		GLint     i;
		GLint     iMax = theTextureWidth >> 1;
		GLint     j;
		GLint     jMax = theTextureHeight >> 1;
		GLint     k = theTextureWidth - 1;
		GLint     l;
		GLint     m;
		GLint     n;

		for( i = 0; i < iMax; i++ )
		{
			y = (GLfloat)i;
			
			for( j = 0; j < jMax; j++ )
			{
				x = (GLfloat)j;
				f = 0.25f*(sinf(b*x) + sinf(b*y) + sinf(b*(x+y)) + sinf(c*sqrtf(x*x+y*y)));
				
				l = i * theTextureWidth;
				m = k * theTextureWidth - l;
				n = k - j;
				
				pattern[l+j] = f;
				pattern[l+n] = f;
				pattern[m+j] = f;
				pattern[m+n] = f;
			} // for
		} // for
	} // if
	
	return (GLvoid *)pattern;
} // texturePixels

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

@end

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

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