X-Git-Url: http://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fgeometry%2Fgeometry.cpp;h=1d7beeb20777747d500bbebf3e6a1300f60f1fee;hb=refs%2Fheads%2Fmaster;hp=8deed860dc0622825153fd07873240bcac91c0a1;hpb=0e069351615f1315a5c7103fe5c849a242f72683;p=gong.git

diff --git a/src/geometry/geometry.cpp b/src/geometry/geometry.cpp
index 8deed86..1d7beeb 100644
--- a/src/geometry/geometry.cpp
+++ b/src/geometry/geometry.cpp
@@ -46,6 +46,16 @@ std::ostream &operator <<(std::ostream &out, const AABB &box) {
 	return out << "AABB(" << box.min << ", " << box.max << ')';
 }
 
+bool Intersection(const AABB &a, const AABB &b) noexcept {
+	if (a.max.x < b.min.x) return false;
+	if (b.max.x < a.min.x) return false;
+	if (a.max.y < b.min.y) return false;
+	if (b.max.y < a.min.y) return false;
+	if (a.max.z < b.min.z) return false;
+	if (b.max.z < a.min.z) return false;
+	return true;
+}
+
 std::ostream &operator <<(std::ostream &out, const Ray &ray) {
 	return out << "Ray(" << ray.orig << ", " << ray.dir << ')';
 }
@@ -217,6 +227,16 @@ std::ostream &operator <<(std::ostream &out, const Plane &plane) {
 	return out << "Plane(" << plane.normal << ", " << plane.dist << ')';
 }
 
+float Distance(const glm::vec3 &point, const Plane &plane) {
+	return std::abs(SignedDistance(point, plane));
+}
+
+float SignedDistance(const glm::vec3 &point, const Plane &plane) {
+	return (
+		plane.A() * point.x + plane.B() * point.y + plane.C() * point.z + plane.D()
+	) / glm::length(plane.normal);
+}
+
 std::ostream &operator <<(std::ostream &out, const Frustum &frustum) {
 	return out << "Frustum(" << std::endl
 		<< "\tleft:   " << frustum.plane[0] << std::endl
@@ -277,6 +297,60 @@ bool CullTest(const AABB &box, const Frustum &frustum) noexcept {
 	}
 	return false;
 }
+
+std::ostream &operator <<(std::ostream &out, const Sphere &s) {
+	return out << "Sphere(" << s.origin << ", " << s.radius << ')';
 }
 
+bool Intersection(
+	const Sphere &a,
+	const Sphere &b,
+	float &dist,
+	glm::vec3 &norm
+) noexcept {
+	glm::vec3 diff(b.origin - a.origin);
+	float dist2 = glm::length2(diff);
+	if (dist2 < std::numeric_limits<float>::epsilon()) {
+		// origins coincide, use smaller of the diameters for
+		// depth and pick arbitrary normal
+		dist = 2.0f * std::min(a.radius, b.radius);
+		norm = glm::vec3(1.0f, 0.0f, 0.0f);
+		return true;
+	}
+	if (dist2 < (a.radius + b.radius) * (a.radius + b.radius)) {
+		dist = std::sqrt(dist2);
+		norm = diff / dist;
+		dist = a.radius - (dist - b.radius);
+		return true;
+	} else {
+		return false;
+	}
+}
+
+bool Intersection(
+	const Sphere &sphere,
+	const Plane &plane,
+	float &dist,
+	glm::vec3 &norm
+) noexcept {
+	float sig_dist = SignedDistance(sphere.origin, plane);
+	dist = sphere.radius - std::abs(sig_dist);
+	if (dist > 0.0f) {
+		norm = sig_dist > 0.0f ? plane.normal : -plane.normal;
+		return true;
+	} else {
+		return false;
+	}
+}
+
+bool Intersection(
+	const Sphere &sphere,
+	const Plane &plane,
+	float &dist
+) noexcept {
+	dist = sphere.radius - SignedDistance(sphere.origin, plane);
+	return dist > 0.0f;
+}
+
+}
 }