X-Git-Url: https://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fgeometry%2Fgeometry.cpp;fp=src%2Fgeometry%2Fgeometry.cpp;h=1d7beeb20777747d500bbebf3e6a1300f60f1fee;hb=48d34439f3d5bc8bebabe9f0ee35970359e61bfa;hp=002c68f0d1ba69760b65d41049e069a2ef2d490a;hpb=bda41b98427c8d34f954dae0dcaf261c5ad6cb43;p=gong.git

diff --git a/src/geometry/geometry.cpp b/src/geometry/geometry.cpp
index 002c68f..1d7beeb 100644
--- a/src/geometry/geometry.cpp
+++ b/src/geometry/geometry.cpp
@@ -302,6 +302,31 @@ 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,