bool intersectSphere(Ray ray, GPUObject obj, out hitInfo hit) { vec3 oc = ray.origin - obj.position; float b = dot(oc, ray.direction); float c = dot(oc, oc) - obj.radius * obj.radius; float h = b * b - c; float t = -b - sqrt(h); t = mix(t, -b + sqrt(h), step(t, 0.0)); hit.t = t; hit.position = ray.origin + ray.direction * t; hit.normal = normalize(hit.position - obj.position); return (h >= 0.0 && t > 0.0); } bool intersectPlane(Ray ray, GPUObject obj, out hitInfo hit) { float d = dot(obj.normal, ray.direction); float t = dot(obj.position - ray.origin, obj.normal) / d; bool valid = t >= 0.0 && d != 0.0; if (!valid) return (false); hit.t = t; hit.position = ray.origin + ray.direction * t; hit.normal = d < 0.0 ? obj.normal : -obj.normal; return (valid); } bool intersectQuad(Ray ray, GPUObject obj, out hitInfo hit) { vec3 normal = normalize(cross(obj.vertex1, obj.vertex2)); float d = dot(normal, ray.direction); if (d == 0.0) return (false); float t = dot(obj.position - ray.origin, normal) / d; if (t <= 0.0) return (false); vec3 p = ray.origin + ray.direction * t - obj.position; float e1 = dot(p, obj.vertex1); float e2 = dot(p, obj.vertex2); 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; hit.t = t; hit.position = p + obj.position; hit.normal = normal * -sign(d); 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 intersectCube(Ray ray, GPUObject obj, out hitInfo hit) { vec3 halfSize = obj.vertex1 * 0.5; vec3 rayOriginLocal = ray.origin - obj.position; vec3 invDir = 1.0 / ray.direction; vec3 t1 = (-halfSize - rayOriginLocal) * invDir; vec3 t2 = (halfSize - rayOriginLocal) * invDir; vec3 tMinVec = min(t1, t2); vec3 tMaxVec = max(t1, t2); float tMin = max(tMinVec.x, max(tMinVec.y, tMinVec.z)); float tMax = min(tMaxVec.x, min(tMaxVec.y, tMaxVec.z)); bool hit_success = (tMax >= tMin) && (tMax > 0.0); if (!hit_success) return false; hit.t = tMin > 0.0 ? tMin : tMax; vec3 hitPointLocal = rayOriginLocal + hit.t * ray.direction; hit.position = hitPointLocal + obj.position; vec3 distances = abs(hitPointLocal) - halfSize; const float epsilon = 1e-4; vec3 signs = sign(hitPointLocal); vec3 masks = step(abs(distances), vec3(epsilon)); hit.normal = normalize(masks * signs); bool inside = all(lessThan(abs(rayOriginLocal), halfSize + vec3(epsilon))); hit.normal *= (inside ? -1.0 : 1.0); return true; } bool intersectCylinder(Ray ray, GPUObject obj, out hitInfo hit) { float radius = obj.normal.x; float height = obj.normal.y; vec3 p = ray.origin - obj.position; vec3 d = ray.direction * mat3(obj.rotation); p = p * mat3(obj.rotation); float half_height = height * 0.5; float a = d.x * d.x + d.z * d.z; float b = p.x * d.x + p.z * d.z; float c = p.x * p.x + p.z * p.z - radius * radius; float h = b * b - a * c; if (h < 0.0) return false; float sqrt_h = sqrt(h); float t = (-b - sqrt_h) / a; if (t <= 0.0) { t = (-b + sqrt_h) / a; if (t <= 0.0) return false; } float y = p.y + t * d.y; if (abs(y) <= half_height) { hit.t = t; hit.position = ray.origin + ray.direction * t; vec3 local_normal = vec3(p.x + t * d.x, 0.0, p.z + t * d.z); hit.normal = normalize(local_normal * inverse(mat3(obj.rotation))); return true; } float cap_t = (sign(y) * half_height - p.y) / d.y; if (cap_t <= 0.0) return false; float cap_x = p.x + cap_t * d.x; float cap_z = p.z + cap_t * d.z; if (cap_x * cap_x + cap_z * cap_z > radius * radius) return false; hit.t = cap_t; hit.position = ray.origin + ray.direction * cap_t; vec3 cap_normal = vec3(0.0, sign(y), 0.0); hit.normal = normalize(cap_normal * inverse(mat3(obj.rotation))); return true; } bool intersect(Ray ray, GPUObject obj, out hitInfo hit) { if (obj.type == 0) return (intersectSphere(ray, obj, hit)); if (obj.type == 1) return (intersectPlane(ray, obj, hit)); if (obj.type == 2 || obj.type == 5) return (intersectQuad(ray, obj, hit)); if (obj.type == 3) return (intersectTriangle(ray, obj, hit)); if (obj.type == 4) return (intersectCube(ray, obj, hit)); if (obj.type == 6) return (intersectCylinder(ray, obj, hit)); return (false); }