/************************************
** cg_init.cpp                     **
** ----------                      **
**                                 **
** Initializes and sets up various **
**   CG shader stuff for OpenGL... ** 
**                                 **
** Chris Wyman (1/6/2003)          **
************************************/

#include "cg_init.h"


/* initialize the program structures                                                               */
/* ---------------------------------                                                               */
/*   If you want to change the files storing your shaders, change them here.                       */
/*   If you want to add more CG programs, change the number in the template header, add them here. */

shader cgProgram[NUM_CG_PROGRAMS] = {
	/*  0 */ { "testVertexShader.cg",			GL_VERTEX_PROGRAM_ARB,   0, 0, NULL },
	/*  1 */ { "testFragmentShader.cg",			GL_FRAGMENT_PROGRAM_ARB, 0, 0, NULL },
	/*  2 */ { "displayDepth.Frag.cg",          GL_FRAGMENT_PROGRAM_ARB, 0, 0, NULL },
};

CGData cgData;

int SetCGParameterv( int progNum, char *paramName, int arraySize, float *array )
{
	CGparameter paramPtr = cgGetNamedParameter( cgData.programs[progNum], paramName );
	if (paramPtr==0) return 0;
	switch( arraySize )
	{
	case 1:
		cgGLSetParameter1fv( paramPtr, array );
		break;
	case 2:
		cgGLSetParameter2fv( paramPtr, array );
		break;
	case 3:
		cgGLSetParameter3fv( paramPtr, array );
		break;
	case 4:
		cgGLSetParameter4fv( paramPtr, array );
		break;
	default:
		printf("Error: SetCGParameterv should have an arraySize in the range [1-4]!");
		return 0;
	}
	return 1;
}

int SetCGParameter( int progNum, char *paramName, float x, float y, float z, float w )
{
	float tmp[4] = {x, y, z, w};	
	return SetCGParameterv( progNum, paramName, 4, tmp );
}

/* call before using a program to set the GL state */
void BindCGProgram( int progNum )
{
	cgGLEnableProfile( cgData.programType[progNum] );
	cgGLBindProgram( cgData.programs[progNum] );
}

/* call after finishing with a program to unset GL state */
void UnbindCGProgram( int progNum )
{
	cgGLDisableProfile( cgData.programType[progNum] );
}

/* double-check required extensions, load shaders, and double check that     */
/* they're valid and we have sufficient resources                            */
int ReloadCGShaders( void )
{
	int i;
	int readError = 0;

	for (i=0;i<NUM_CG_PROGRAMS;i++)
	{
		cgDestroyProgram( cgData.programs[i] );
		cgData.programs[i] = cgCreateProgramFromFile( cgData.shaderContext, CG_SOURCE, cgProgram[i].filename,
													  cgData.programType[i], "main", 0 );
		if (!cgData.programs[i])
		{
			CGerror  err = cgGetError();
			const char* errStr = cgGetErrorString( err );
			printf("CG Error: %s\n", errStr );
			readError++;
		}
		else
			cgGLLoadProgram( cgData.programs[i] );
	}

	printf("(+) Successfully reloaded %d CG shaders\n", i-readError );
	return (readError > 0 ? 1 : 0);
}

/* double-check required extensions, load shaders, and double check that     */
/* they're valid and we have sufficient resources                            */
void InitCGPrograms( void )
{
	int i;
	int readErrors=0;
	
	cgData.shaderContext = cgCreateContext();

	cgData.vertProfile = cgGLGetLatestProfile( CG_GL_VERTEX );
	cgData.fragProfile = cgGLGetLatestProfile( CG_GL_FRAGMENT );
	cgGLSetOptimalOptions( cgData.vertProfile );
	cgGLSetOptimalOptions( cgData.fragProfile );

	for (i=0;i<NUM_CG_PROGRAMS;i++)
	{
		cgData.programs[i] = cgCreateProgramFromFile( cgData.shaderContext, CG_SOURCE, cgProgram[i].filename,
													  cgProgram[i].type == GL_VERTEX_PROGRAM_ARB ? cgData.vertProfile : cgData.fragProfile, 
													  "main", 0 );
		if (!cgData.programs[i])
		{
			printf("%s\n", cgGetErrorString( cgGetError() ) );
			readErrors++;
		}

		cgData.programName[i] = cgProgram[i].filename;
		cgData.programType[i] = cgProgram[i].type == GL_VERTEX_PROGRAM_ARB ? cgData.vertProfile : cgData.fragProfile;
		cgGLLoadProgram( cgData.programs[i] );
	}

	printf("     (-) Successfully read %d CG shaders\n", i-readErrors );
}