GLSL and GPU Programming

const int wid=320, ht=256;
char pixels[wid*ht];
int render_mbrot(void)
{
	for (int y=0;y<ht;y++) 
	for (int x=0;x<wid;x++)
	{
		float cx=x*(3.0/(float)wid)-1.5;
		float cy=y*(2.0/(float)ht)-1.0;
		float zr=cx, zi=cy; // complex number
		int count=0;
		for (count=0;count<255;count++) {
			// z = z^2 + c = (zr+i*zi)^2 + c
			float nzr=zr*zr-zi*zi + cx;
			float nzi=2.0*zr*zi + cy;
			if (nzr*nzr+nzi*nzi > 4.0) break;
			zr=nzr; zi=nzi;
		}
		pixels[y*wid+x]=((unsigned char)(zr*255.0/4.0))&0xff;
		// (count&0xff); //<- classic iteration count render
	}
	return 0;
}

int foo(void) {
	double t=time_function(render_mbrot);
	double nspix=(t*1.0e9)/(wid*ht);
	std::cout<<"render time: "<<nspix<<" ns/pixel\n";

	// Write a greyscale PPM output file (so we can see what we've rendered)
	std::ofstream os("out.ppm",std::ios_base::out|std::ios_base::binary);
	os<<"P5\n";
	os<<wid<<" "<<ht<<" 255\n";
	os.write(pixels,wid*ht);
	os.close();
	return 0;
}

(Try this in NetRun now!)

float cx=texcoords.x*(3.0)-1.5;
float cy=texcoords.y*(2.0)-1.0;
float zr=cx, zi=cy; // complex number
int count=0;
for (count=0;count<255;count++) {
	// z = z^2 + c = (zr+i*zi)^2 + c
	float nzr=zr*zr-zi*zi + cx;
	float nzi=2.0*zr*zi + cy;
	if (nzr*nzr+nzi*nzi > 4.0) break;
	zr=nzr; zi=nzi;
}
gl_FragColor = fract(vec4(zr,zi,count,1.0));

(Try this in NetRun now!)