textures, overlay images, libimago

[demo_prior] / sdr / whitted.p.glsl

diff --git a/sdr/whitted.p.glsl b/sdr/whitted.p.glsl
index 368903d..0124f1b 100644 (file)
--- a/sdr/whitted.p.glsl
+++ b/sdr/whitted.p.glsl
@@ -18,15 +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(-20, 20, 30);
+const vec3 light_pos = vec3(-10, 50, 30);
 
 void main()
 {
@@ -70,20 +71,24 @@ 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));
 }
 
+#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)
 {
        HitPoint hit, nearest;
 
        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) {
@@ -94,18 +99,18 @@ bool isect_scene(in vec3 ro, in vec3 rd, out HitPoint hit_res)
        return true;
 }
 
-#define FLOOR_OFFS     vec3(2.0, 0.0, 0.0)
-
-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 - FLOOR_OFFS, 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;
 }
 
@@ -161,3 +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);
+}