port from perforce

hgplus/ShaderMinifier/tests/real/gfx monitor/raytrace.fs

@@ -0,0 +1,191 @@
+// FragmentProgram
+
+const int raytraceDepth = 8;
+
+varying vec3 org,dir;
+
+struct Ray
+{
+	vec3 org;
+	vec3 dir;
+};
+struct Sphere
+{
+	vec3 c;
+	float r;
+	vec3 col;
+};
+struct Plane
+{
+	vec3 p;
+	vec3 n;
+	vec3 col;
+};
+
+struct Intersection
+{
+    float t;
+    vec3 p;     // hit point
+    vec3 n;     // normal
+    int hit;
+    vec3 col;
+};
+
+void shpere_intersect(Sphere s,  Ray ray, inout Intersection isect)
+{
+    // rs = ray.org - sphere.c
+    vec3 rs = ray.org - s.c;
+    float B = dot(rs, ray.dir);
+    float C = dot(rs, rs) - (s.r * s.r);
+    float D = B * B - C;
+
+    if (D > 0.0)
+    {
+		float t = -B - sqrt(D);
+		if ( (t > 0.0) && (t < isect.t) )
+		{
+			isect.t = t;
+			isect.hit = 1;
+
+			// calculate normal.
+			vec3 p = vec3(ray.org.x + ray.dir.x * t,
+						  ray.org.y + ray.dir.y * t,
+						  ray.org.z + ray.dir.z * t);
+			vec3 n = p - s.c;
+			n = normalize(n);
+			isect.n = n;
+			isect.p = p;
+			isect.col = s.col;
+		}
+	}
+}
+
+void plane_intersect(Plane pl, Ray ray, inout Intersection isect)
+{
+	// d = -(p . n)
+	// t = -(ray.org . n + d) / (ray.dir . n)
+	float d = -dot(pl.p, pl.n);
+	float v = dot(ray.dir, pl.n);
+
+	if (abs(v) < 1.0e-6)
+		return; // the plane is parallel to the ray.
+
+    float t = -(dot(ray.org, pl.n) + d) / v;
+
+    if ( (t > 0.0) && (t < isect.t) )
+    {
+		isect.hit = 1;
+		isect.t   = t;
+		isect.n   = pl.n;
+
+		vec3 p = vec3(ray.org.x + t * ray.dir.x,
+					  ray.org.y + t * ray.dir.y,
+					  ray.org.z + t * ray.dir.z);
+		isect.p = p;
+		float offset = 0.2;
+		vec3 dp = p + offset;
+		if ((mod(dp.x, 1.0) > 0.5 && mod(dp.z, 1.0) > 0.5)
+		||  (mod(dp.x, 1.0) < 0.5 && mod(dp.z, 1.0) < 0.5))
+			isect.col = pl.col;
+		else
+			isect.col = pl.col * 0.5;
+	}
+}
+
+Sphere sphere[3];
+Plane plane;
+void Intersect(Ray r, inout Intersection i)
+{
+	for (int c = 0; c < 3; c++)
+	{
+		shpere_intersect(sphere[c], r, i);
+	}
+	plane_intersect(plane, r, i);
+}
+
+int seed = 0;
+float random()
+{
+	seed = int(mod(float(seed)*1364.0+626.0, 509.0));
+	return float(seed)/509.0;
+}
+vec3 computeLightShadow(in Intersection isect)
+{
+	int i, j;
+    int ntheta = 16;
+    int nphi   = 16;
+    float eps  = 0.0001;
+
+    // Slightly move ray org towards ray dir to avoid numerical probrem.
+    vec3 p = vec3(isect.p.x + eps * isect.n.x,
+                  isect.p.y + eps * isect.n.y,
+                  isect.p.z + eps * isect.n.z);
+
+	vec3 lightPoint = vec3(5,5,5);
+    Ray ray;
+	ray.org = p;
+	ray.dir = normalize(lightPoint - p);
+
+	Intersection lisect;
+	lisect.hit = 0;
+	lisect.t = 1.0e+30;
+	lisect.n = lisect.p = lisect.col = vec3(0, 0, 0);
+	Intersect(ray, lisect);
+	if (lisect.hit != 0)
+		return vec3(0.0,0.0,0.0);
+	else
+	{
+		float shade = max(0.0, dot(isect.n, ray.dir));
+		shade = pow(shade,3.0) + shade * 0.5;
+		return vec3(shade,shade,shade);
+	}
+	
+}
+
+void main()
+{
+	sphere[0].c   = vec3(-2.0, 0.0, -3.5);
+	sphere[0].r   = 0.5;
+	sphere[0].col = vec3(1,0.3,0.3);
+	sphere[1].c   = vec3(-0.5, 0.0, -3.0);
+	sphere[1].r   = 0.5;
+	sphere[1].col = vec3(0.3,1,0.3);
+	sphere[2].c   = vec3(1.0, 0.0, -2.2);
+	sphere[2].r   = 0.5;
+	sphere[2].col = vec3(0.3,0.3,1);
+	plane.p = vec3(0,-0.5, 0);
+	plane.n = vec3(0, 1.0, 0);
+	plane.col = vec3(1,1, 1);
+	seed = int(mod(dir.x * dir.y * 4525434.0, 65536.0));
+	
+	Ray r;
+	r.org = org;
+	r.dir = normalize(dir);
+	vec4 col = vec4(0,0,0,1);
+	float eps  = 0.0001;
+	vec3 bcol = vec3(1,1,1);
+	for (int j = 0; j < raytraceDepth; j++)
+	{
+		Intersection i;
+		i.hit = 0;
+		i.t = 1.0e+30;
+		i.n = i.p = i.col = vec3(0, 0, 0);
+			
+		Intersect(r, i);
+		if (i.hit != 0)
+		{
+			col.rgb += bcol * i.col * computeLightShadow(i);
+			bcol *= i.col;
+		}
+		else
+		{
+			break;
+		}
+				
+		r.org = vec3(i.p.x + eps * i.n.x,
+					 i.p.y + eps * i.n.y,
+					 i.p.z + eps * i.n.z);
+		r.dir = reflect(r.dir, vec3(i.n.x, i.n.y, i.n.z));
+	}
+	gl_FragColor = col;
+}