X-Git-Url: https://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fgeometry.cpp;fp=src%2Fgeometry.cpp;h=c5f806997fae8cee4d9e26311ec0067dd607e808;hb=4d0ef1687987a0801469c7262f81efd36636605a;hp=0000000000000000000000000000000000000000;hpb=ac8765b510707d77cac9620778f40ddf3a4ad2a2;p=blank.git

diff --git a/src/geometry.cpp b/src/geometry.cpp
new file mode 100644
index 0000000..c5f8069
--- /dev/null
+++ b/src/geometry.cpp
@@ -0,0 +1,102 @@
+#include "geometry.hpp"
+
+
+namespace blank {
+
+bool Intersection(const Ray &ray, const AABB &aabb, const glm::mat4 &M, float *dist) {
+	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;
+
+	{ // 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 (t1 > t2) {
+				std::swap(t1, t2);
+			}
+			if (t1 > t_min) {
+				t_min = t1;
+			}
+			if (t2 < t_max) {
+				t_max = t2;
+			}
+			if (t_max < t_min) {
+				return false;
+			}
+		} else {
+			if (aabb.min.x - e > 0.0f || aabb.max.x < 0.0f) {
+				return false;
+			}
+		}
+	}
+
+	{ // Y
+		const glm::vec3 yaxis(M[1].x, M[1].y, M[1].z);
+		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 (t1 > t2) {
+				std::swap(t1, t2);
+			}
+			if (t1 > t_min) {
+				t_min = t1;
+			}
+			if (t2 < t_max) {
+				t_max = t2;
+			}
+			if (t_max < t_min) {
+				return false;
+			}
+		} else {
+			if (aabb.min.y - e > 0.0f || aabb.max.y < 0.0f) {
+				return false;
+			}
+		}
+	}
+
+	{ // Z
+		const glm::vec3 zaxis(M[2].x, M[2].y, M[2].z);
+		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 (t1 > t2) {
+				std::swap(t1, t2);
+			}
+			if (t1 > t_min) {
+				t_min = t1;
+			}
+			if (t2 < t_max) {
+				t_max = t2;
+			}
+			if (t_max < t_min) {
+				return false;
+			}
+		} else {
+			if (aabb.min.z - e > 0.0f || aabb.max.z < 0.0f) {
+				return false;
+			}
+		}
+	}
+
+	if (dist) {
+		*dist = t_min;
+	}
+	return true;
+}
+
+}