X-Git-Url: http://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fmodel%2Fgeometry.cpp;h=a4ac5006d55a019544f122a035af5d98d21cf308;hb=0d580658b896dfec07466c31ae4847455724ee95;hp=416d930c4f68d0c24a0f690851264b98556b855b;hpb=b7d09e1e35ef90282c97509e0020b20db3c7ea9f;p=blank.git

diff --git a/src/model/geometry.cpp b/src/model/geometry.cpp
index 416d930..a4ac500 100644
--- a/src/model/geometry.cpp
+++ b/src/model/geometry.cpp
@@ -1,10 +1,41 @@
 #include "geometry.hpp"
 
 #include <limits>
+#include <glm/gtx/matrix_cross_product.hpp>
+#include <glm/gtx/optimum_pow.hpp>
+#include <glm/gtx/transform.hpp>
 
 
 namespace blank {
 
+glm::mat3 find_rotation(const glm::vec3 &a, const glm::vec3 &b) noexcept {
+	glm::vec3 v(cross(a, b));
+	if (iszero(v)) {
+		// a and b are parallel
+		if (iszero(a - b)) {
+			// a and b are identical
+			return glm::mat3(1.0f);
+		} else {
+			// a and b are opposite
+			// create arbitrary unit vector perpendicular to a and
+			// rotate 180° around it
+			glm::vec3 arb(a);
+			if (std::abs(a.x - 1.0f) > std::numeric_limits<float>::epsilon()) {
+				arb.x += 1.0f;
+			} else {
+				arb.y += 1.0f;
+			}
+			glm::vec3 axis(normalize(cross(a, arb)));
+			return glm::mat3(glm::rotate(PI, axis));
+		}
+	}
+	float mv = length_squared(v);
+	float c = dot(a, b);
+	float f = (1 - c) / mv;
+	glm::mat3 vx(matrixCross3(v));
+	return glm::mat3(1.0f) + vx + (pow2(vx) * f);
+}
+
 bool Intersection(
 	const Ray &ray,
 	const AABB &aabb,
@@ -35,7 +66,7 @@ bool Intersection(
 				return false;
 			}
 		} else {
-			if (aabb.min[i] - e < 0.0f || -aabb.max[i] - e > 0.0f) {
+			if (aabb.min[i] - e > 0.0f || aabb.max[i] - e < 0.0f) {
 				return false;
 			}
 		}
@@ -47,24 +78,98 @@ bool Intersection(
 		*dist = t_min;
 	}
 	if (normal) {
-		glm::vec4 norm(0.0f);
 		if (min_all.x > min_all.y) {
 			if (min_all.x > min_all.z) {
-				norm.x = t2.x < t1.x ? 1 : -1;
+				normal->x = t2.x < t1.x ? 1 : -1;
 			} else {
-				norm.z = t2.z < t1.z ? 1 : -1;
+				normal->z = t2.z < t1.z ? 1 : -1;
 			}
 		} else if (min_all.y > min_all.z) {
-			norm.y = t2.y < t1.y ? 1 : -1;
+			normal->y = t2.y < t1.y ? 1 : -1;
 		} else {
-			norm.z = t2.z < t1.z ? 1 : -1;
+			normal->z = t2.z < t1.z ? 1 : -1;
 		}
-		norm = M * norm;
-		*normal = glm::vec3(norm);
 	}
 	return true;
 }
 
+
+bool Intersection(
+	const AABB &a_box,
+	const glm::mat4 &a_m,
+	const AABB &b_box,
+	const glm::mat4 &b_m,
+	float &depth,
+	glm::vec3 &normal
+) noexcept {
+	glm::vec3 a_corners[8] = {
+		glm::vec3(a_m * glm::vec4(a_box.min.x, a_box.min.y, a_box.min.z, 1)),
+		glm::vec3(a_m * glm::vec4(a_box.min.x, a_box.min.y, a_box.max.z, 1)),
+		glm::vec3(a_m * glm::vec4(a_box.min.x, a_box.max.y, a_box.min.z, 1)),
+		glm::vec3(a_m * glm::vec4(a_box.min.x, a_box.max.y, a_box.max.z, 1)),
+		glm::vec3(a_m * glm::vec4(a_box.max.x, a_box.min.y, a_box.min.z, 1)),
+		glm::vec3(a_m * glm::vec4(a_box.max.x, a_box.min.y, a_box.max.z, 1)),
+		glm::vec3(a_m * glm::vec4(a_box.max.x, a_box.max.y, a_box.min.z, 1)),
+		glm::vec3(a_m * glm::vec4(a_box.max.x, a_box.max.y, a_box.max.z, 1)),
+	};
+
+	glm::vec3 b_corners[8] = {
+		glm::vec3(b_m * glm::vec4(b_box.min.x, b_box.min.y, b_box.min.z, 1)),
+		glm::vec3(b_m * glm::vec4(b_box.min.x, b_box.min.y, b_box.max.z, 1)),
+		glm::vec3(b_m * glm::vec4(b_box.min.x, b_box.max.y, b_box.min.z, 1)),
+		glm::vec3(b_m * glm::vec4(b_box.min.x, b_box.max.y, b_box.max.z, 1)),
+		glm::vec3(b_m * glm::vec4(b_box.max.x, b_box.min.y, b_box.min.z, 1)),
+		glm::vec3(b_m * glm::vec4(b_box.max.x, b_box.min.y, b_box.max.z, 1)),
+		glm::vec3(b_m * glm::vec4(b_box.max.x, b_box.max.y, b_box.min.z, 1)),
+		glm::vec3(b_m * glm::vec4(b_box.max.x, b_box.max.y, b_box.max.z, 1)),
+	};
+
+	glm::vec3 axes[6] = {
+		glm::vec3(a_m * glm::vec4(1, 0, 0, 0)),
+		glm::vec3(a_m * glm::vec4(0, 1, 0, 0)),
+		glm::vec3(a_m * glm::vec4(0, 0, 1, 0)),
+		glm::vec3(b_m * glm::vec4(1, 0, 0, 0)),
+		glm::vec3(b_m * glm::vec4(0, 1, 0, 0)),
+		glm::vec3(b_m * glm::vec4(0, 0, 1, 0)),
+	};
+
+	depth = std::numeric_limits<float>::infinity();
+	int min_axis = 0;
+
+	int cur_axis = 0;
+	for (const glm::vec3 &axis : axes) {
+		float a_min = std::numeric_limits<float>::infinity();
+		float a_max = -std::numeric_limits<float>::infinity();
+		for (const glm::vec3 &corner : a_corners) {
+			float val = glm::dot(corner, axis);
+			a_min = std::min(a_min, val);
+			a_max = std::max(a_max, val);
+		}
+
+		float b_min = std::numeric_limits<float>::infinity();
+		float b_max = -std::numeric_limits<float>::infinity();
+		for (const glm::vec3 &corner : b_corners) {
+			float val = glm::dot(corner, axis);
+			b_min = std::min(b_min, val);
+			b_max = std::max(b_max, val);
+		}
+
+		if (a_max < b_min || b_max < a_min) return false;
+
+		float overlap = std::min(a_max, b_max) - std::max(a_min, b_min);
+		if (overlap < depth) {
+			depth = overlap;
+			min_axis = cur_axis;
+		}
+
+		++cur_axis;
+	}
+
+	normal = axes[min_axis];
+	return true;
+}
+
+
 bool CullTest(const AABB &box, const glm::mat4 &MVP) noexcept {
 	// transform corners into clip space
 	glm::vec4 corners[8] = {