random trace tweaks

src/ssa.rs

@@ -491,9 +491,10 @@ impl SSATape {
                 .begin_function(
                     float,
                     if with_module { Some(1000) } else { None },
-                    spirv::FunctionControl::DONT_INLINE
-                        | spirv::FunctionControl::PURE
-                        | spirv::FunctionControl::CONST,
+                    //spirv::FunctionControl::DONT_INLINE
+                    spirv::FunctionControl::INLINE
+                       | spirv::FunctionControl::PURE
+                       | spirv::FunctionControl::CONST,
                     point_fn_type,
                 )
                 .unwrap();
@@ -1285,7 +1286,7 @@ impl SSATape {
             b.end_function().unwrap();
         }
 
-        {
+        /*{
             let _scene = b
                 .begin_function(
                     vec2,
@@ -2819,7 +2820,7 @@ impl SSATape {
                 }
             }
             b.end_function().unwrap();
-        }
+        }*/
 
         let module = b.module();
 

src/trace.frag.glsl

@@ -1,5 +1,3 @@
-//  global fragment shader
-
 #version 460
 #extension GL_GOOGLE_include_directive:require
 #include "include.glsl"
@@ -12,41 +10,25 @@ layout(depth_greater) out float gl_FragDepth;
 layout(location = 0) out uint material;
 
 const float EPSILON = .001;
-const uint MAX_STEPS = 50;
-const float NEARPLANE = 0.;
 float FARPLANE = length(object_uniforms.dimensions / 32.);
 
-vec2 spheretracing(vec3 ori, vec3 dir, out vec3 p) {
-    vec2 td = vec2(NEARPLANE, 1.);
-    p = ori;
-    td.y = scene(vec4(p, camera_uniforms.campos_and_time.w)) * .98;
-    td.x += td.y;
-    p = fma(dir, vec3(td.x), ori);
-    for (int i = 0; td.y > EPSILON && td.x < FARPLANE; i++) {
-        td.y = scene(vec4(p, camera_uniforms.campos_and_time.w)) * .98;
-        td.x += td.y;
-        p = fma(dir, vec3(td.x), ori);
-    }
-    return td;
-}
-
-//Implicit Surface Entrypoint
 void main() {
     vec3 raypos = pos.xyz;
-
-    vec3 p;
     vec3 raydir = normalize(raypos - (pc.inv_world * vec4(camera_uniforms.campos_and_time.xyz, 1)).xyz);
 
-    vec2 td = spheretracing(raypos, raydir, p);
-
-    if (td.y < EPSILON)
-    {
-        vec4 tpoint = camera_uniforms.proj_view * pc.world * vec4(p, 1);
-        gl_FragDepth = (tpoint.z / tpoint.w);
-        material = object_uniforms.material;
-    }
-    else
-    {
-        discard;
-    }
+    vec3 p = raypos;
+    float total_dist = 0.;
+    do {
+        float dist = scene(vec4(p, camera_uniforms.campos_and_time.w)) * .98;
+        total_dist += dist;
+        p = fma(raydir, vec3(total_dist), raypos);
+        if (dist < EPSILON) {
+            vec4 tpoint = camera_uniforms.proj_view * pc.world * vec4(p, 1);
+            gl_FragDepth = (tpoint.z / tpoint.w);
+            material = object_uniforms.material;
+            return;
+        } else if (total_dist > FARPLANE) {
+            discard;
+        }
+    } while (true);
 }