distance function generation from level data, first pass

[raydungeon] / sdr / raydungeon.p.glsl

diff --git a/sdr/raydungeon.p.glsl b/sdr/raydungeon.p.glsl
index 8a66df7..c10be18 100644 (file)
--- a/sdr/raydungeon.p.glsl
+++ b/sdr/raydungeon.p.glsl
@@ -1,5 +1,117 @@
+uniform float aspect;
+uniform mat4 matrix;
+uniform mat3 dirmatrix;
+
+#define DIST_THRES     1e-3
+#define MAX_ITER       250
+#define MAX_STEP       1.0
+
+vec3 raymarch(inout vec3 p, in vec3 dir, out float depth);
+vec3 shade(in vec3 p, in vec3 dir, in float dist, in float total_dist);
+vec3 backdrop(in vec3 dir);
+float eval_sdf(in vec3 p);
+vec3 eval_grad(in vec3 p, float dist);
+vec3 primray(in vec2 uv, out vec3 org);
+
+float boxdist(in vec3 p, in vec3 b);
+float sphdist(in vec3 p, in vec3 sp, in float srad);
+
 void main()
 {
-       vec3 col = vec3(gl_TexCoord[0].st, 1.0);
-       gl_FragColor = vec4(col, 1.0);
+       vec2 uv = gl_TexCoord[0].st;
+       vec3 rorg;
+       vec3 rdir = primray(uv, rorg);
+       float depth;
+
+       gl_FragColor.rgb = raymarch(rorg, rdir, depth);
+       gl_FragColor.a = 1.0;
+
+       vec4 projp = gl_ProjectionMatrix * vec4(0.0, 0.0, -depth, 1.0);
+       float zval = projp.z / projp.w;
+
+       gl_FragDepth = zval;
+}
+
+vec3 raymarch(inout vec3 p, in vec3 dir, out float depth)
+{
+       float d, total_d = 0.0;
+
+       for(int i=0; i<MAX_ITER; i++) {
+               if((d = eval_sdf(p)) <= DIST_THRES) {
+                       depth = total_d;
+                       return shade(p, dir, d, total_d);
+               }
+
+               d = min(d, MAX_STEP);
+
+               p = p + dir * d;
+               total_d += d;
+       }
+
+       depth = -gl_DepthRange.far;
+       return backdrop(dir);
+}
+
+vec3 shade(in vec3 p, in vec3 dir, in float dist, in float total_dist)
+{
+    const vec3 kd = vec3(1.0, 0.3, 0.1);
+    const vec3 ks = vec3(0.7, 0.7, 0.7);
+    const vec3 ldir = normalize(vec3(-1.0, 1.0, -1.5));
+    const vec3 vdir = vec3(0.0, 0.0, -1.0);
+
+    vec3 diffuse = vec3(0.0, 0.0, 0.0);
+    vec3 specular = vec3(0.0, 0.0, 0.0);
+    
+    vec3 n = eval_grad(p, dist);
+       return n * 0.5 + 0.5;
+    vec3 hdir = normalize(ldir + vdir);
+
+    float ndotl = max(dot(n, ldir), 0.0);
+    float ndoth = max(dot(n, hdir), 0.0);
+    
+    diffuse += kd * ndotl;
+    specular += ks * pow(ndoth, 50.0);
+    
+    float fog = clamp(300.0 / (total_dist * total_dist), 0.0, 1.0);
+
+    return mix(backdrop(dir), diffuse + specular, fog);
+}
+
+vec3 backdrop(in vec3 dir)
+{
+       return vec3(0.1, 0.1, 0.1);
+}
+
+#define DELTA  1e-4
+vec3 eval_grad(in vec3 p, float dist)
+{
+       float dfdx = eval_sdf(p + vec3(DELTA, 0.0, 0.0)) - dist;
+       float dfdy = eval_sdf(p + vec3(0.0, DELTA, 0.0)) - dist;
+       float dfdz = eval_sdf(p + vec3(0.0, 0.0, DELTA)) - dist;
+       return normalize(vec3(dfdx, dfdy, dfdz));
+}
+
+vec3 primray(in vec2 uv, out vec3 org)
+{
+       vec3 origin = (gl_ModelViewMatrixInverse * vec4(0.0, 0.0, 0.0, 1.0)).xyz;
+       org = origin;
+
+       vec2 nuv = uv * 2.0 - 1.0;
+       vec4 cp_near = vec4(nuv, -1.0, 1.0);
+
+       vec4 vdir = gl_ProjectionMatrixInverse * cp_near;
+       vec4 wdir = gl_ModelViewMatrixInverse * vec4(vdir.xyz, 0.0);
+
+       return normalize(wdir.xyz);
+}
+
+float boxdist(in vec3 p, in vec3 b)
+{
+       vec3 q = abs(p) - b;
+       return length(max(q, 0.0)) + min(max(q.x, max(q.y, q.z)), 0.0);
+}
+
+float sphdist(in vec3 p, in vec3 sp, in float srad)
+{
+       return length(p - sp) - srad;
 }