const Frustum& Camera::GetFrustum() const
{
// Use projection_ instead of GetProjection() so that Y-flip has no effect. Update first if necessary
if (projectionDirty_)
UpdateProjection();
if (frustumDirty_)
{
if (customProjection_)
frustum_.Define(projection_ * GetView());
else
{
// If not using a custom projection, prefer calculating frustum from projection parameters instead of matrix
// for better accuracy
if (!orthographic_)
frustum_.Define(fov_, aspectRatio_, zoom_, GetNearClip(), GetFarClip(), GetEffectiveWorldTransform());
else
frustum_.DefineOrtho(orthoSize_, aspectRatio_, zoom_, GetNearClip(), GetFarClip(), GetEffectiveWorldTransform());
}
frustumDirty_ = false;
}
return frustum_;
}
bool Camera::ObjectFrustumCulling( const RenderObject& obj )
{
const AABB& aabb = obj.m_worldAABB;
//物体坐标转换到相机空间进行裁减
VEC4 pos(aabb.GetCenter(), 1.0f);
Common::Transform_Vec4_By_Mat44(pos, pos, GetViewMatrix());
float n = GetNearClip();
float f = GetFarClip();
float fov = GetFov();
float half_w = n * std::tan(fov/2);
float half_h = half_w / GetAspectRatio();
//检测前后面
if(-pos.z+aabb.m_boundingRadius <= n || -pos.z-aabb.m_boundingRadius >= f)
return true;
//检测左右面
float planeX = half_w * pos.z / -n;
if(pos.x - planeX >= aabb.m_boundingRadius ||
pos.x + aabb.m_boundingRadius <= -planeX)
return true;
//检测上下面
float planeY = half_h * pos.z / -n;
if(pos.y - planeY >= aabb.m_boundingRadius ||
pos.y + aabb.m_boundingRadius <= -planeY)
return true;
return false;
}
Frustum Camera::GetViewSpaceFrustum() const
{
if (projectionDirty_)
UpdateProjection();
Frustum ret;
if (customProjection_)
ret.Define(projection_);
else
{
if (!orthographic_)
ret.Define(fov_, aspectRatio_, zoom_, GetNearClip(), GetFarClip());
else
ret.DefineOrtho(orthoSize_, aspectRatio_, zoom_, GetNearClip(), GetFarClip());
}
return ret;
}
bool Camera::IsProjectionValid() const
{
return GetFarClip() > GetNearClip();
}
