+ | Triangle intersection

shaders/intersect.glsl

@@ -31,23 +31,19 @@ bool intersectPlane(Ray ray, GPUObject obj, out hitInfo hit)
 
 bool intersectQuad(Ray ray, GPUObject obj, out hitInfo hit)
 {
-    // obj.edge1 and obj.edge2 are the two edge vectors from quad origin
-    vec3 normal = normalize(cross(obj.edge1, obj.edge2));
+    vec3 normal = normalize(cross(obj.vertex1, obj.vertex2));
     float d = dot(normal, ray.direction);
     float t = dot(obj.position - ray.origin, normal) / d;
 
     if (t <= 0.0 || d == 0.0) return (false);
     
-    // Get hit point relative to quad origin
     vec3 p = ray.origin + ray.direction * t - obj.position;
     
-    // Project hit point onto edges using dot product
-    float e1 = dot(p, obj.edge1);
-    float e2 = dot(p, obj.edge2);
+    float e1 = dot(p, obj.vertex1);
+    float e2 = dot(p, obj.vertex2);
     
-    // Check if point is inside quad using edge lengths
-    float l1 = dot(obj.edge1, obj.edge1);
-    float l2 = dot(obj.edge2, obj.edge2);
+    float l1 = dot(obj.vertex1, obj.vertex1);
+    float l2 = dot(obj.vertex2, obj.vertex2);
     
     bool inside = e1 >= 0.0 && e1 <= l1 && e2 >= 0.0 && e2 <= l2;
     
@@ -58,6 +54,60 @@ bool intersectQuad(Ray ray, GPUObject obj, out hitInfo hit)
     return (inside);
 }
 
+// bool intersectTriangle(Ray ray, GPUObject obj, out hitInfo hit)
+// {
+//     vec3 pvec = cross(ray.direction, obj.vertex2);
+//     float det = dot(obj.vertex1, pvec);
+//     vec3 tvec = ray.origin - obj.position;
+    
+//     float invDet = 1.0 / det;
+//     float u = dot(tvec, pvec) * invDet;
+//     vec3 qvec = cross(tvec, obj.vertex1);
+//     float v = dot(ray.direction, qvec) * invDet;
+//     float t = dot(obj.vertex2, qvec) * invDet;
+    
+//     bool valid = abs(det) > 1e-8 &&
+//                 u >= 0.0 && u <= 1.0 &&
+//                 v >= 0.0 && (u + v) <= 1.0 &&
+//                 t > 0.0;
+    
+//     hit.t = t;
+//     hit.position = ray.origin + ray.direction * t;
+//     hit.normal = obj.normal * sign(-dot(ray.direction, obj.normal));
+    
+//     return (valid);
+// }
+
+bool intersectTriangle(Ray ray, GPUObject obj, out hitInfo hit)
+{
+    vec3 pvec = cross(ray.direction, obj.vertex2);
+    float det = dot(obj.vertex1, pvec);
+    
+    if (abs(det) < 1e-8) return (false); // det < 0.0
+    
+    float invDet = 1.0 / det;
+    
+    vec3 tvec = ray.origin - obj.position;
+    
+    float u = dot(tvec, pvec) * invDet;
+    if (u < 0.0 || u > 1.0) return (false);
+    
+    vec3 qvec = cross(tvec, obj.vertex1);
+    float v = dot(ray.direction, qvec) * invDet;
+    if (v < 0.0 || u + v > 1.0) return (false);
+    
+    float t = dot(obj.vertex2, qvec) * invDet;
+    if (t <= 0.0) return (false);
+    
+    hit.t = t;
+    hit.position = ray.origin + ray.direction * t;
+    
+    vec3 normal = obj.normal;
+    hit.normal = dot(ray.direction, normal) < 0.0 ? normal : -normal;
+        
+    return (true);
+}
+
 bool intersect(Ray ray, GPUObject obj, out hitInfo hit)
 {
     if (obj.type == 0)
@@ -66,6 +116,8 @@ bool intersect(Ray ray, GPUObject obj, out hitInfo hit)
         return (intersectPlane(ray, obj, hit));
     if (obj.type == 2)
         return (intersectQuad(ray, obj, hit));
+    if (obj.type == 3)
+        return (intersectTriangle(ray, obj, hit));
 
     return (false);
 }