struct ViewportRect
{
	u16 x, w, y, h;
	float zMin, zMax;//if both are zero, will be changed to min=0, max=1
};

struct PassState
{
	void Release();
};

struct RenderPass
{
	void Release();
	PassIndex Index() const;
	u32 NumTargets() const;
	RenderPass* ReplaceTargets( Scope& a, uint numTargets, TextureId* targets, TextureId depthStencil ) const;//must match existing number of targets, and depth target nullness
};

class RenderPassWriter
{
public:
	RenderPassWriter();
	~RenderPassWriter();

	// Either pass a Scope allocator, or pass 'Persistent'.
	// In the Persistent case: the resulting PassState/RenderPass must have their Release function called.
	// In the Scope case: the PassState/RenderPass will be released automatically by the supplied Scope. Do not call Release on them.
	void Begin( GpuDevice& gpu, Scope& a );
	void Begin( GpuDevice& gpu, Persistent_tag a );

	PassState* CreatePassState( const StateGroup* defaults, const StateGroup* overrides=0 );
	PassState* CreatePassState( u32 numDefaults, const StateGroup*const* defaults, u32 numOverrides=0, const StateGroup*const* overrides=0 );

	RenderPass* Create( const char* name, PassIndex, const PassState* state, u32 numTargets, TextureId* targets, TextureId depthStencil=TextureId(0), const ViewportRect* viewport=0, const RwResourceState* rw=0 );
	RenderPass* Create( const char* name, PassIndex, const PassState* state, TextureId target, TextureId depthStencil=TextureId(0), const ViewportRect* viewport=0, const RwResourceState* rw=0 );

	void End();
private:
	GpuDevice* m_gpu;
	Scope* m_alloc;
};