X-Git-Url: http://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fgeometry%2Fprimitive.hpp;h=52a3617835245382b6e2014091116cc881fc3c87;hb=3185bad87c06739e4ec19b456c7158437ba9621f;hp=351a3a432e1c17d3662b9544012e5c997c22328c;hpb=4fbf5a3c1b0e530706023f5fc4be2f68d30ea645;p=blank.git

diff --git a/src/geometry/primitive.hpp b/src/geometry/primitive.hpp
index 351a3a4..52a3617 100644
--- a/src/geometry/primitive.hpp
+++ b/src/geometry/primitive.hpp
@@ -1,8 +1,11 @@
 #ifndef BLANK_GEOMETRY_PRIMITIVE_HPP_
 #define BLANK_GEOMETRY_PRIMITIVE_HPP_
 
+#include "../graphics/glm.hpp"
+
 #include <algorithm>
-#include <glm/glm.hpp>
+#include <iosfwd>
+#include <glm/gtx/norm.hpp>
 
 
 namespace blank {
@@ -20,13 +23,52 @@ struct AABB {
 	glm::vec3 Center() const noexcept {
 		return min + (max - min) * 0.5f;
 	}
+
+	/// return distance between origin and farthest vertex
+	float OriginRadius() const noexcept {
+		glm::vec3 high(glm::max(glm::abs(min), glm::abs(max)));
+		return glm::length(high);
+	}
 };
 
+std::ostream &operator <<(std::ostream &, const AABB &);
+
+// TODO: this should really use setters/getters for dir and inv_dir so
+//       manipulating code doesn't "forget" to call Update()
 struct Ray {
 	glm::vec3 orig;
 	glm::vec3 dir;
+
+	glm::vec3 inv_dir;
+
+	void Update() noexcept {
+		inv_dir = 1.0f / dir;
+	}
+
+	/// get shortest distance of this ray's line to given point
+	float Distance(const glm::vec3 &point) const noexcept {
+		// d = |(x2-x1)×(x1-x0)|/|x2-x1|
+		// where x0 is point, and x1 and x2 are points on the line
+		// for derivation, see http://mathworld.wolfram.com/Point-LineDistance3-Dimensional.html
+		// x1 = orig
+		// x2-x1 = dir, which means |x2-x1| is 1.0
+		return glm::length(glm::cross(dir, orig - point));
+	}
+	float DistanceSquared(const glm::vec3 &point) const noexcept {
+		return glm::length2(glm::cross(dir, orig - point));
+	}
 };
 
+std::ostream &operator <<(std::ostream &, const Ray &);
+
+/// axis aligned boolean ray/box intersection test
+/// if true, dist constains distance from ray's origin to intersection point
+bool Intersection(
+	const Ray &,
+	const AABB &,
+	float &dist) noexcept;
+
+/// detailed oriented ray/box intersection test
 bool Intersection(
 	const Ray &,
 	const AABB &,
@@ -34,6 +76,8 @@ bool Intersection(
 	float *dist = nullptr,
 	glm::vec3 *normal = nullptr) noexcept;
 
+/// matrices may translate and rotate, but must not scale/shear/etc
+/// (basically the first three columns must have unit length)
 bool Intersection(
 	const AABB &a_box,
 	const glm::mat4 &a_m,
@@ -42,7 +86,72 @@ bool Intersection(
 	float &depth,
 	glm::vec3 &normal) noexcept;
 
-bool CullTest(const AABB &box, const glm::mat4 &MVP) noexcept;
+
+struct Plane {
+	glm::vec3 normal;
+	float dist;
+
+	float &A() noexcept { return normal.x; }
+	float &B() noexcept { return normal.y; }
+	float &C() noexcept { return normal.z; }
+	float &D() noexcept { return dist; }
+	float A() const noexcept { return normal.x; }
+	float B() const noexcept { return normal.y; }
+	float C() const noexcept { return normal.z; }
+	float D() const noexcept { return dist; }
+
+	Plane(const glm::vec3 &n, float d)
+	: normal(n), dist(d) { }
+	explicit Plane(const glm::vec4 &abcd)
+	: normal(abcd), dist(abcd.w) { }
+
+	void Normalize() noexcept {
+		const float l = glm::length(normal);
+		normal /= l;
+		dist /= l;
+	}
+};
+
+std::ostream &operator <<(std::ostream &, const Plane &);
+
+struct Frustum {
+	Plane plane[6];
+	Plane &Left() noexcept { return plane[0]; }
+	Plane &Right() noexcept { return plane[1]; }
+	Plane &Bottom() noexcept { return plane[2]; }
+	Plane &Top() noexcept { return plane[3]; }
+	Plane &Near() noexcept { return plane[4]; }
+	Plane &Far() noexcept { return plane[5]; }
+	const Plane &Left() const noexcept { return plane[0]; }
+	const Plane &Right() const noexcept { return plane[1]; }
+	const Plane &Bottom() const noexcept { return plane[2]; }
+	const Plane &Top() const noexcept { return plane[3]; }
+	const Plane &Near() const noexcept { return plane[4]; }
+	const Plane &Far() const noexcept { return plane[5]; }
+
+	/// create frustum from transposed MVP
+	explicit Frustum(const glm::mat4 &mat)
+	: plane{
+		Plane{ mat[3] + mat[0] },
+		Plane{ mat[3] - mat[0] },
+		Plane{ mat[3] + mat[1] },
+		Plane{ mat[3] - mat[1] },
+		Plane{ mat[3] + mat[2] },
+		Plane{ mat[3] - mat[2] },
+	} { }
+
+	void Normalize() noexcept {
+		for (Plane &p : plane) {
+			p.Normalize();
+		}
+	}
+};
+
+std::ostream &operator <<(std::ostream &, const Plane &);
+std::ostream &operator <<(std::ostream &, const Frustum &);
+
+bool CullTest(const AABB &box, const glm::mat4 &) noexcept;
+bool CullTest(const AABB &box, const Frustum &) noexcept;
 
 }