1.1 --- a/sdr/demo.p.glsl	Sun Apr 15 02:22:13 2012 +0300
     1.2 +++ b/sdr/demo.p.glsl	Sun Apr 15 07:19:01 2012 +0300
     1.3 @@ -1,9 +1,32 @@
     1.4 +#define NBALLS	3
     1.5 +
     1.6 +uniform float energy[NBALLS];
     1.7 +uniform vec3 pos[NBALLS];
     1.8 +
     1.9 +float eval(vec3 p)
    1.10 +{
    1.11 +	float val = 0.0;
    1.12 +
    1.13 +	for(int i=0; i<NBALLS; i++) {
    1.14 +		vec3 dif = p - pos[i];
    1.15 +		float len_sq = dot(dif, dif);
    1.16 +		val += 0.1 * energy[i] / len_sq;
    1.17 +	}
    1.18 +	return val;
    1.19 +}
    1.20 +
    1.21 +#define OFFS	0.01
    1.22 +
    1.23  void main()
    1.24  {
    1.25  	vec3 pos = gl_TexCoord[0].xyz * 2.0 - 1.0;
    1.26  
    1.27 -	float len = length(pos);
    1.28 -	float val = 0.1 / (len * len);
    1.29 +	float val = eval(pos);
    1.30  
    1.31 -	gl_FragColor = vec4(-pos / len, val);
    1.32 +	vec3 grad;
    1.33 +	grad.x = eval(pos + vec3(OFFS, 0.0, 0.0)) - eval(pos - vec3(OFFS, 0.0, 0.0));
    1.34 +	grad.y = eval(pos + vec3(0.0, OFFS, 0.0)) - eval(pos - vec3(0.0, OFFS, 0.0));
    1.35 +	grad.z = eval(pos + vec3(0.0, 0.0, OFFS)) - eval(pos - vec3(0.0, 0.0, OFFS));
    1.36 +
    1.37 +	gl_FragColor = vec4(grad, val);
    1.38  }