temp intersect

src/blitz/maths/Physics.cpp

@@ -1,18 +1,28 @@
 #include "blitz/maths/Physics.h"
 
 #include "blitz/maths/Maths.h"
+#include "blitz/misc/Log.h"
 #include <cmath>
 
 namespace blitz {
 namespace maths {
 
-float Intersects(const Ray& ray, const AABB& aabb) {
-	Vec3f dirFrac{
+/**
+ * @brief Returns `true` if the half-line `ray` _strictly_ intersects with `aabb`,
+ *  and `false` if it _strictly_ doesn't intersect.
+ *  Note that if it only intersects with corners, edges, or sides of the box,
+ *  or if any coordinate in `ray` is `NAN` or `inf` or if any coordinate in
+ *  `aabb` is `NAN` the result is unspecified.
+ * */
+float Distance(const Ray& ray, const AABB& aabb) {
+	// r.dir is unit direction vector of ray
+	Vec3f dirFrac = {
 		1.0f / ray.direction.x,
 		1.0f / ray.direction.y,
 		1.0f / ray.direction.z,
 	};
-
+	// lb is the corner of AABB with minimal coordinates - left bottom, rt is maximal corner
+	// r.org is origin of ray
 	float t1 = (aabb.from.x - ray.origin.x) * dirFrac.x;
 	float t2 = (aabb.to.x - ray.origin.x) * dirFrac.x;
 	float t3 = (aabb.from.y - ray.origin.y) * dirFrac.y;
@@ -24,17 +34,19 @@ float Intersects(const Ray& ray, const AABB& aabb) {
 	float tmax = std::min(std::min(std::max(t1, t2), std::max(t3, t4)), std::max(t5, t6));
 
 	// if tmax < 0, ray (line) is intersecting AABB, but the whole AABB is behind us
-	if (tmax < 0) {
-		return -1;
-	}
-
 	// if tmin > tmax, ray doesn't intersect AABB
-	if (tmin > tmax) {
-		return -1;
+	if (tmax < 0 || tmin > tmax) {
+		return -1.0f;
 	}
 
 	return tmin;
 }
 
+bool Intersects(const Ray& ray, const AABB& aabb) {
+	float distance = Distance(ray, aabb);
+	utils::LOG(std::to_string(distance));
+	return distance >= 0.0f;
+}
+
 }  // namespace maths
 }  // namespace blitz