port from perforce

hgplus/ShaderMinifier/tests/real/extatique/raymarch.fs

@@ -0,0 +1,59 @@
+varying vec3 dir;
+
+
+float flr(vec3 p, float f)
+{
+	return abs(f - p.y);
+}
+
+float sph(vec3 p, vec4 spr)
+{
+	return length(spr.xyz - p) - spr.w;
+}
+
+float iso_tore(vec3 p, vec3 center, float r1, float r2) 
+{
+	p -= center;
+	float xx = sqrt(p.x * p.x + p.z * p.z) - r1;
+	float dist = sqrt(xx * xx + p.y * p.y) - r2;
+	return mix(dist, dist, 0.9);
+}
+
+float scene(vec3 p)
+{
+	float d = iso_tore(p, vec3(0,0,15), 2.0, 0.5);
+	return d;
+}
+
+vec3 getN(vec3 p)
+{
+	float eps = 0.01;
+	return normalize(vec3(
+		scene(p+vec3(eps,0,0))-scene(p-vec3(eps,0,0)),
+		scene(p+vec3(0,eps,0))-scene(p-vec3(0,eps,0)),
+		scene(p+vec3(0,0,eps))-scene(p-vec3(0,0,eps))
+	));
+}
+
+
+void main()
+{
+	float g,d = 0.0;
+	vec3 p = vec3(0);
+	vec3 ndir = normalize(dir);
+	
+	for(int i = 0; i < 64; i++)
+	{
+		d = scene(p);
+		p = p + d * ndir;
+	}
+	if(d > 1.0)
+	{
+		gl_FragColor = vec4(1.0,0.0,0.0,1.0);
+	
+		return;
+	}
+	
+	vec3 n = getN(p);
+	gl_FragColor = vec4(n, 1.0);
+}