//	Function DumpScreenToFile
//	void DumpScreenToFile(char* filename, int width, int height, int component);
//	
//	Reads the color or depth values from a rectangular area from (0,0) to (width,height) 
//	on the screen and dumps it to a text file.
//
//	Use component value as 	
//				0 for Red color component
//				1 for Green color component
//				2 for Blue color component
//				3 for Alpha color component
//				4 for Depth component
//
//	Example usage:
//	DumpScreenToFile("Screen.txt", 400, 300, 0);
//
#include <stdio.h>

void WriteToFile(char* filename, float* screenData, int w, int h, float scale, float bias)
{
	FILE *fp;
	fopen_s(&fp,filename,"w");
	for(int j=0; j < h; j++)
	{
		for(int i=0; i < w; i++)
			fprintf(fp,"%f ",screenData[(j*w+i)]*scale+bias);
		fprintf(fp,"\n");
	}
	fclose(fp);
}

void DumpScreenToFile(char* filename, int width, int height, int component)
{
	float* screenData = new float[height*width];
	glReadBuffer(GL_FRONT);

	if (component == 0)
		glReadPixels(0,0,width,height,GL_RED  ,GL_FLOAT,screenData);
	else if (component == 1)
		glReadPixels(0,0,width,height,GL_GREEN,GL_FLOAT,screenData);
	else if (component == 2)
		glReadPixels(0,0,width,height,GL_BLUE ,GL_FLOAT,screenData);
	else if (component == 3)
		glReadPixels(0,0,width,height,GL_ALPHA,GL_FLOAT,screenData);
	else if (component == 4)
		glReadPixels(0,0,width,height,GL_DEPTH_COMPONENT,GL_FLOAT,screenData);
	else
		return;


	float scale = 1;
	float bias  = 0;
	if (component == 4)
	{
		glGetFloatv (GL_DEPTH_SCALE,&scale);
		glGetFloatv (GL_DEPTH_BIAS, &bias);
	}
	WriteToFile(filename, screenData , width , height, scale, bias);

	delete[] screenData;
}