Graphics/Billboard: Fix bounding volume

ChangeLog.md

@@ -83,6 +83,7 @@ Nazara Engine:
 - Add support for emissive and normal maps in .mtl loader using custom keywords ([map_]emissive and [map_]normal)
 - Music, Sound and SoundEmitter are now movable
 - Fixed Sound copy which was not copying looping state
+- Fixed Billboard bounding volume
 
 Nazara Development Kit:
 - Added ImageWidget (#139)

src/Nazara/Graphics/Billboard.cpp

@@ -33,9 +33,12 @@ namespace Nz
 
 	void Billboard::MakeBoundingVolume() const
 	{
-		constexpr float sqrt2 = float(M_SQRT2);
+		// As billboard always face the screen, we must take its maximum size in account on every axis
+		float maxSize = float(M_SQRT2) * std::max(m_size.x, m_size.y);
 
-		m_boundingVolume.Set(Vector3f(0.f), sqrt2 * m_size.x * Vector3f::Right() + sqrt2 * m_size.y * Vector3f::Down());
+		Nz::Vector3f halfSize = (maxSize * Vector3f::Right() + maxSize * Vector3f::Down() + maxSize * Vector3f::Forward()) / 2.f;
+
+		m_boundingVolume.Set(-halfSize, halfSize);
 	}
 
 	BillboardLibrary::LibraryMap Billboard::s_library;