Pick Func

void CDXScene::Pick(int x, int y, CDXMesh * mesh, CDXPicker & picker)
{
	CDXVec3 vPickRayDir;
	CDXVec3 vPickRayOrig;

	const CDXMatrix* pmatProj = g_Camera.GetProjMatrix();

	// Compute the vector of the pick ray in screen space
	CDXVec3 v;
	v.x = (((2.0f * x) / g_Camera.GetWidth()) - 1) / pmatProj->_11;
	v.y = -(((2.0f * y) / g_Camera.GetHeight()) - 1) / pmatProj->_22;
	v.z = 1.0f;

	// Get the inverse view matrix
	const CDXMatrix matView = *g_Camera.GetViewMatrix();
	const CDXMatrix matWorld = *g_Camera.GetWorldMatrix();
	CDXMatrix mWorldView = matWorld * matView;
	CDXMatrix m;
	D3DXMatrixInverse( &m, NULL, &mWorldView );

	// Transform the screen space pick ray into 3D space
	vPickRayDir.x = v.x * m._11 + v.y * m._21 + v.z * m._31;
	vPickRayDir.y = v.x * m._12 + v.y * m._22 + v.z * m._32;
	vPickRayDir.z = v.x * m._13 + v.y * m._23 + v.z * m._33;
	vPickRayOrig.x = m._41;
	vPickRayOrig.y = m._42;
	vPickRayOrig.z = m._43;

	// Run pick on given mesh
	mesh->Pick(vPickRayOrig, vPickRayDir, picker, false);

	if (picker.Mirror()) {
		vPickRayDir.x = -vPickRayDir.x;
		vPickRayOrig.x = -vPickRayOrig.x;

		mesh->Pick(vPickRayOrig, vPickRayDir, picker, true);
	}
}