textures, overlay images, libimago

[demo_prior] / sdr / whitted.p.glsl

diff --git a/sdr/whitted.p.glsl b/sdr/whitted.p.glsl
index fc197f6..0124f1b 100644 (file)
--- a/sdr/whitted.p.glsl
+++ b/sdr/whitted.p.glsl
@@ -18,10 +18,16 @@ vec3 backdrop(in vec3 dir);
 
 bool isect_scene(in vec3 ro, in vec3 rd, out HitPoint hit);
 
-bool isect_floor(in vec3 ro, in vec3 rd, float rad, out HitPoint hit);
+bool isect_floor(in vec3 ro, in vec3 rd, in vec2 sz, out HitPoint hit);
 bool isect_plane(in vec3 ro, in vec3 rd, in vec4 plane, out HitPoint hit);
 bool isect_sphere(in vec3 ro, in vec3 rd, in vec3 pos, float rad, out HitPoint hit);
 
+vec3 tex_chess(in vec3 col1, in vec3 col2, in vec2 spos);
+
+const Material mtl_sph = Material(vec3(1.0, 0.0, 0.0), vec3(1.0, 1.0, 1.0), 80.0);
+const Material mtl_floor = Material(vec3(0.5, 0.5, 0.5), vec3(0.0, 0.0, 0.0), 1.0);
+
+const vec3 light_pos = vec3(-10, 50, 30);
 
 void main()
 {
@@ -39,7 +45,22 @@ void main()
 
 vec3 shade(in vec3 ro, in vec3 rd, in HitPoint hit)
 {
-       return (hit.norm * 0.5 + 0.5) * hit.mtl.diffuse;
+       HitPoint shadow_hit;
+       vec3 ldir = light_pos - hit.pos;
+
+       vec3 col = vec3(0.03, 0.03, 0.03);      // ambient
+
+       if(!isect_scene(hit.pos + hit.norm * 0.01, ldir, shadow_hit) || shadow_hit.dist > 1.0) {
+               vec3 l = normalize(ldir);
+               vec3 v = normalize(-rd);
+               vec3 h = normalize(v + l);
+               float ndotl = max(dot(hit.norm, l), 0.0);
+               float ndoth = max(dot(hit.norm, h), 0.0);
+
+               col += hit.mtl.diffuse * ndotl + hit.mtl.specular * pow(ndoth, hit.mtl.shin);
+       }
+
+       return col;
 }
 
 #define M_PI   3.1415926
@@ -50,8 +71,8 @@ vec3 backdrop(in vec3 dir)
        return mix(vec3(0.8, 0.3, 0.2), vec3(0.2, 0.3, 0.8), smoothstep(-0.1, 0.1, dir.y));
 }
 
-const Material mtl_sph = Material(vec3(1.0, 0.0, 0.0), vec3(1.0, 1.0, 1.0), 80.0);
-const Material mtl_floor = Material(vec3(0.5, 0.5, 0.5), vec3(0.0, 0.0, 0.0), 1.0);
+#define FLOOR_OFFS     vec3(3.0, 0.0, 0.0)
+#define FLOOR_SIZE     vec2(5.5, 15.0)
 
 bool isect_scene(in vec3 ro, in vec3 rd, out HitPoint hit_res)
 {
@@ -59,14 +80,15 @@ bool isect_scene(in vec3 ro, in vec3 rd, out HitPoint hit_res)
 
        nearest.dist = 10000.0;
 
-       if(isect_sphere(ro, rd, vec3(0.0, 0.0, 0.0), 1.0, hit)) {
+       if(isect_sphere(ro, rd, vec3(1.0, 0.0, 0.0), 1.0, hit)) {
                nearest = hit;
                nearest.mtl = mtl_sph;
        }
 
-       if(isect_floor(ro, rd, 5.0, hit) && hit.dist < nearest.dist) {
+       if(isect_floor(ro, rd, FLOOR_SIZE, hit) && hit.dist < nearest.dist) {
                nearest = hit;
                nearest.mtl = mtl_floor;
+               nearest.mtl.diffuse = tex_chess(vec3(1.0, 0.0, 0.0), vec3(1.0, 1.0, 0.0), hit.surfpos);
        }
 
        if(nearest.dist >= 10000.0) {
@@ -77,15 +99,18 @@ bool isect_scene(in vec3 ro, in vec3 rd, out HitPoint hit_res)
        return true;
 }
 
-bool isect_floor(in vec3 ro, in vec3 rd, float rad, out HitPoint hit)
+bool isect_floor(in vec3 ro, in vec3 rd, in vec2 sz, out HitPoint hit)
 {
-       if(!isect_plane(ro, rd, vec4(0.0, 1.0, 0.0, -1.0), hit)) {
+       if(!isect_plane(ro - FLOOR_OFFS, rd, vec4(0.0, 1.0, 0.0, -1.8), hit)) {
                return false;
        }
 
-       float d = max(abs(hit.pos.x), abs(hit.pos.z));
-       if(d >= rad) return false;
+       if(abs(hit.pos.x) >= sz.x || abs(hit.pos.z) >= sz.y) {
+               return false;
+       }
 
+       hit.pos += FLOOR_OFFS;
+       hit.surfpos /= sz * 2.0;
        return true;
 }
 
@@ -101,6 +126,10 @@ bool isect_plane(in vec3 ro, in vec3 rd, in vec4 plane, out HitPoint hit)
        vec3 pdir = pp - ro;
        float t = dot(pdir, plane.xyz) / ndotrd;
 
+       if(t < 1e-6) {
+               return false;
+       }
+
        hit.dist = t;
        hit.pos = ro + rd * t;
        hit.norm = plane.xyz;
@@ -137,3 +166,13 @@ bool isect_sphere(in vec3 ro, in vec3 rd, in vec3 pos, float rad, out HitPoint h
        hit.surfpos.y = acos(hit.norm.y);
        return true;
 }
+
+vec3 tex_chess(in vec3 col1, in vec3 col2, in vec2 spos)
+{
+       float foo = step(0.5, mod(spos.x * 8.0, 1.0)) * 2.0 - 1.0;
+       float bar = step(0.5, mod(spos.y * 24.0, 1.0)) * 2.0 - 1.0;
+
+       float xor = (foo * bar) * 0.5 + 0.5;
+
+       return mix(col1, col2, xor);
+}