Make raymarching example slightly more interesting

Author: themkat

example/raymarch.frag

@@ -10,7 +10,6 @@ const float MAX_DISTANCE = 10000.0;
 
 out vec4 color;
 
-// TODO: a struct of dist + material id? 
 struct Hit {
   float dist;
   int material_id;
@@ -40,37 +39,92 @@ float smin( float a, float b, float k ) {
     return -k*log2(r);
 }
 
-// box, again thanks to iquilezlez
+// standard GLSL noise function of internet legend. Adapted to 3 dims
+float noise(vec3 co){
+  return fract(sin(dot(co, vec3(12.9898, 78.233, 69.78))) * 43758.5453);
+}
+
+// iqquillez fbm subtraction logic
+// renamed for clarity. Found no better way of doing it, so copy paste it is :P
+float random_radius_sphere( ivec3 i, vec3 f, ivec3 c ) {
+  float rad = 0.5*noise((i + c));
+  return length(f-vec3(c)) - rad;
+}
+
+float eight_random_spheres(vec3 p) {
+  ivec3 i = ivec3(floor(p));
+  vec3 f = fract(p);
+  return min(min(min(random_radius_sphere(i,f,ivec3(0,0,0)),
+                     random_radius_sphere(i,f,ivec3(0,0,1))),
+                 min(random_radius_sphere(i,f,ivec3(0,1,0)),
+                     random_radius_sphere(i,f,ivec3(0,1,1)))),
+             min(min(random_radius_sphere(i,f,ivec3(1,0,0)),
+                     random_radius_sphere(i,f,ivec3(1,0,1))),
+                 min(random_radius_sphere(i,f,ivec3(1,1,0)),
+                     random_radius_sphere(i,f,ivec3(1,1,1)))));
+}
+
+// </iqquillez fbm subtraction logic>
+
+// box, again thanks to iqquillez
 float round_box(vec3 p, vec3 b, float r) {
   vec3 q = abs(p) - b + r;
   return length(max(q,0.0)) + min(max(q.x,max(q.y,q.z)),0.0) - r;
 }
 
-
-// TODO: maybe have a function for our blob structure here? then the scene can just call that function and have botht he distance to it + material?
-//       then we can have some blocks or other stone material using some noise to create them
-
-float scene(vec3 pos) {
-  int num_spheres = 10;
+Hit blob_structure(vec3 pos) {
+  int num_spheres = 8;
   float dist = sphere(pos, vec3(0.0), 1.0);
   for(int i = 1; i < num_spheres; i++) {
     dist = smin(dist, sphere(pos, vec3(cos(elapsed_time / i), -tan(elapsed_time/i), sin(elapsed_time)), 0.7), 0.2);
   }
-  return smin(dist, plane(pos, vec3(0.0, 1.0, 0.0), 4.0), 0.2);
+  return Hit(smin(dist, round_box(pos + vec3(0.0, 4.0, 0.0), vec3(3.0, 1.0, 3.0), 0.5), 0.2), 0);
+}
+
+float eroded_block(vec3 pos, vec3 dims) {
+  float dist = round_box(pos, dims, 0.2);
+  // fbm from iq
+  float s = 1.0;
+  for( int i=0; i<4; i++ ) {
+    float n = s*eight_random_spheres(pos);
+    dist = max( dist, -n);
+    pos = mat3(0.00, 1.60, 1.20, 
+               -1.60, 0.72,-0.96,
+               -1.20,-0.96, 1.28)*pos;
+    s = 0.5*s;
+  }
+
+  return dist;
+}
+
+// a weird basin containing the pink blobby goo
+Hit basin(vec3 pos) {
+  float dist = eroded_block(pos + vec3(4.0, 5.0, 0.0), vec3(2.0, 4.0, 4.0));
+  dist = min(dist, eroded_block(pos + vec3(-4.0, 5.0, 0.0), vec3(2.0, 4.0, 4.0)));
+
+  float hole_box = eroded_block(pos + vec3(0.0, 4.0, 4.0), vec3(3.0, 10.0, 0.5));
+  float smaller_box = round_box(pos + vec3(0.0, -4.0, 4.0), vec3(2.0, 1.0, 0.8), 0.2);
+  dist = min(dist, max(hole_box, -smaller_box));
+  
+  return Hit(dist, 1);
+}
+
+Hit scene(vec3 pos) {
+  return hit_min(hit_min(blob_structure(pos + vec3(0.0, 0.0, 2.0)), basin(pos + vec3(0.0, 0.0, 2.0))),
+                 Hit(plane(pos, vec3(0.0, 1.0, 0.0), 4.0), 2));
 }
 
 vec3 normal(vec3 pos) {
-  return normalize(vec3(scene(pos + vec3(0.01, 0.0, 0.0)) - scene(pos - vec3(0.01, 0.0, 0.0)),
-                        scene(pos + vec3(0.0, 0.01, 0.0)) - scene(pos - vec3(0.0, 0.01, 0.0)),
-                        scene(pos + vec3(0.0, 0.0, 0.01)) - scene(pos - vec3(0.0, 0.0, 0.01))));
+  return normalize(vec3(scene(pos + vec3(0.01, 0.0, 0.0)).dist - scene(pos - vec3(0.01, 0.0, 0.0)).dist,
+                        scene(pos + vec3(0.0, 0.01, 0.0)).dist - scene(pos - vec3(0.0, 0.01, 0.0)).dist,
+                        scene(pos + vec3(0.0, 0.0, 0.01)).dist - scene(pos - vec3(0.0, 0.0, 0.01)).dist));
 }
 
-// TODO: refactor to a general raymarching
 // probably unintuitive method as well. TOok it out of my ass
 float shadow_march(vec3 pos, vec3 ray_dir) {
   float t = 0.5;
   while(t < 200.0) {
-    float dist = scene(pos + t*ray_dir);
+    float dist = scene(pos + t*ray_dir).dist;
     if(dist < 0.001) {
       // could be 0, but like the way occluding factor 0.1 looks like
       return 0.1;
@@ -83,7 +137,7 @@ float shadow_march(vec3 pos, vec3 ray_dir) {
 }
 
 void main() {
-  // upside down?
+  // upside down, but saves a calc
   vec2 uv = gl_FragCoord.xy / vec2(screen_width, screen_height);
   vec3 ray_dir = vec3(uv * 2.0 - 1.0, -1.0);
   vec3 cam_pos = vec3(0.0, 0.0, 5.0);
@@ -94,25 +148,36 @@ void main() {
   int i = 0;
   while (i < MAX_ITERATIONS && t < MAX_DISTANCE) {
     vec3 pos = cam_pos + t*ray_dir;
-    float dist = scene(pos);
-    // TODO: more advanced color
-    if (dist < 0.001) {
+    Hit hit = scene(pos);
+    if (hit.dist < 0.001) {
       vec3 light_dir = normalize(light_pos - pos);
       vec3 normal = normal(pos);
       float diffuse_intensity = max(0.0, dot(light_dir, normal));
       vec3 half_vec = normalize(light_dir + -ray_dir);
       float specular = max(0.0, pow(dot(half_vec, normal), 256));
       float shadow = shadow_march(pos, light_dir);
 
-      // TODO: what is the best way to have different colors for each material?
-      
+      // stupid material handling
+      vec3 ambient_color = vec3(1.0, 0.8, 0.9);
+      vec3 diffuse_color = vec3(1.0, 0.8, 0.9);
+      if (hit.material_id == 1) {
+        ambient_color = vec3(0.1, 0.1, 0.1);
+        diffuse_color = vec3(0.4, 0.4, 0.4);
+        specular = 0.0;
+      } else if (hit.material_id == 2) {
+        ambient_color = vec3(0.7, 0.9, 0.7);
+        // TODO: more interesting material
+        diffuse_color = noise(pos) * vec3(0.9, 0.9, 0.9);
+        specular = 0.0;
+      }
 
-      color = vec4(0.3*vec3(1.0, 0.8, 0.9) + shadow*vec3(1.0, 0.8, 0.9) * diffuse_intensity + shadow*vec3(1.0)*specular, 1.0);
+      color = vec4(0.3*ambient_color + shadow*diffuse_color * diffuse_intensity + shadow*vec3(1.0)*specular, 1.0);
       return;
     }
 
-    t += dist; 
+    t += hit.dist;
   }
 
-  color = vec4(0.0);
+  // TODO: more interesting color
+  color = mix(vec4(0.9, 0.9, 0.9, 1.0), vec4(0.4, 0.6, 0.8, 1.0), 0.8 - uv.y / 2.0);
 }