 uniform float startx;
 uniform float starty;
 
+// anti-aliasing used by mandelbrot and julia
 float smooth(float x, float y, float i){
 	float zn = sqrt( x*x + y*y );
 	float nu = log( log(zn) / log(2) ) / log(2);

	return 1.0;
}

vec4 color(float mandel, float julia){
	return vec4(julia*2.0, julia/2.0+mandel/2.0, mandel*2.0, 1.0);
}

// uniform values from main program
uniform vec2  screen;
uniform vec2  center;
uniform int mode;
