X-Git-Url: http://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fgeometry.cpp;h=df48ad3deac2c440f66d89f8fb69e69aac1e9b88;hb=8881c507009521d08648560984c0f50166224542;hp=c5f806997fae8cee4d9e26311ec0067dd607e808;hpb=4d0ef1687987a0801469c7262f81efd36636605a;p=blank.git

diff --git a/src/geometry.cpp b/src/geometry.cpp
index c5f8069..df48ad3 100644
--- a/src/geometry.cpp
+++ b/src/geometry.cpp
@@ -1,31 +1,43 @@
 #include "geometry.hpp"
 
+#include <limits>
+
 
 namespace blank {
 
-bool Intersection(const Ray &ray, const AABB &aabb, const glm::mat4 &M, float *dist) {
+bool Intersection(
+	const Ray &ray,
+	const AABB &aabb,
+	const glm::mat4 &M,
+	float *dist,
+	glm::vec3 *normal
+) {
 	float t_min = 0.0f;
 	float t_max = 1.0e5f;
 	const glm::vec3 aabb_pos(M[3].x, M[3].y, M[3].z);
 	const glm::vec3 delta = aabb_pos - ray.orig;
 
+	glm::vec3 t1(t_min, t_min, t_min), t2(t_max, t_max, t_max);
+	bool x_swap = false, y_swap = false, z_swap = false;
+
 	{ // X
 		const glm::vec3 xaxis(M[0].x, M[0].y, M[0].z);
 		const float e = glm::dot(xaxis, delta);
 		const float f = glm::dot(ray.dir, xaxis);
 
-		if (std::abs(f) > 0.001f) {
-			float t1 = (e + aabb.min.x) / f;
-			float t2 = (e + aabb.max.x) / f;
+		if (std::abs(f) > std::numeric_limits<float>::epsilon()) {
+			t1.x = (e + aabb.min.x) / f;
+			t2.x = (e + aabb.max.x) / f;
 
-			if (t1 > t2) {
-				std::swap(t1, t2);
+			if (t1.x > t2.x) {
+				std::swap(t1.x, t2.x);
+				x_swap = true;
 			}
-			if (t1 > t_min) {
-				t_min = t1;
+			if (t1.x > t_min) {
+				t_min = t1.x;
 			}
-			if (t2 < t_max) {
-				t_max = t2;
+			if (t2.x < t_max) {
+				t_max = t2.x;
 			}
 			if (t_max < t_min) {
 				return false;
@@ -42,18 +54,19 @@ bool Intersection(const Ray &ray, const AABB &aabb, const glm::mat4 &M, float *d
 		const float e = glm::dot(yaxis, delta);
 		const float f = glm::dot(ray.dir, yaxis);
 
-		if (std::abs(f) > 0.001f) {
-			float t1 = (e + aabb.min.y) / f;
-			float t2 = (e + aabb.max.y) / f;
+		if (std::abs(f) > std::numeric_limits<float>::epsilon()) {
+			t1.y = (e + aabb.min.y) / f;
+			t2.y = (e + aabb.max.y) / f;
 
-			if (t1 > t2) {
-				std::swap(t1, t2);
+			if (t1.y > t2.y) {
+				std::swap(t1.y, t2.y);
+				y_swap = true;
 			}
-			if (t1 > t_min) {
-				t_min = t1;
+			if (t1.y > t_min) {
+				t_min = t1.y;
 			}
-			if (t2 < t_max) {
-				t_max = t2;
+			if (t2.y < t_max) {
+				t_max = t2.y;
 			}
 			if (t_max < t_min) {
 				return false;
@@ -70,18 +83,19 @@ bool Intersection(const Ray &ray, const AABB &aabb, const glm::mat4 &M, float *d
 		const float e = glm::dot(zaxis, delta);
 		const float f = glm::dot(ray.dir, zaxis);
 
-		if (std::abs(f) > 0.001f) {
-			float t1 = (e + aabb.min.z) / f;
-			float t2 = (e + aabb.max.z) / f;
+		if (std::abs(f) > std::numeric_limits<float>::epsilon()) {
+			t1.z = (e + aabb.min.z) / f;
+			t2.z = (e + aabb.max.z) / f;
 
-			if (t1 > t2) {
-				std::swap(t1, t2);
+			if (t1.z > t2.z) {
+				std::swap(t1.z, t2.z);
+				z_swap = true;
 			}
-			if (t1 > t_min) {
-				t_min = t1;
+			if (t1.z > t_min) {
+				t_min = t1.z;
 			}
-			if (t2 < t_max) {
-				t_max = t2;
+			if (t2.z < t_max) {
+				t_max = t2.z;
 			}
 			if (t_max < t_min) {
 				return false;
@@ -96,6 +110,19 @@ bool Intersection(const Ray &ray, const AABB &aabb, const glm::mat4 &M, float *d
 	if (dist) {
 		*dist = t_min;
 	}
+	if (normal) {
+		if (t1.x > t1.y) {
+			if (t1.x > t1.z) {
+				*normal = glm::vec3(x_swap ? 1 : -1, 0, 0);
+			} else {
+				*normal = glm::vec3(0, 0, z_swap ? 1 : -1);
+			}
+		} else if (t1.y > t1.z) {
+			*normal = glm::vec3(0, y_swap ? 1 : -1, 0);
+		} else {
+			*normal = glm::vec3(0, 0, z_swap ? 1 : -1);
+		}
+	}
 	return true;
 }