LUMIERA.clone/src/proc/state.hpp

123 lines
4.3 KiB
C++

/*
STATE.hpp - Key Interface representing a render process and encapsulating state
Copyright (C) Lumiera.org
2008, Hermann Vosseler <Ichthyostega@web.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef PROC_INTERFACE_STATE_H
#define PROC_INTERFACE_STATE_H
#include "pre.hpp"
#include "proc/common.hpp"
#include "lib/frameid.hpp"
#include "proc/engine/buffhandle.hpp"
#include <cstddef>
namespace engine {
using lumiera::FrameID;
using lumiera::NodeID;
class StateAdapter;
class BuffTableStorage;
/**
* Abstraction denoting the state of a currently ongoing render/calculation
* process, as it is tied to the supporting facilities of the backend.
* An State (subclass) instance is the sole connection for the render node
* to invoke services of the backend needed to carry out the calculations.
*
* @see engine::RenderInvocation top-level entrance point
* @see nodeinvocation.hpp impl. used from \em within the nodes
*/
class State
{
public:
/** allocate a new writable buffer with type and size according to
* the BufferDescriptor. The actual provider of this buffer depends
* on the State implementation; it could be a temporary, located in
* the cache, used for feeding calculated frames over a network, etc.
* @return a BuffHandle encapsulating the information necessary to get
* at the actual buffer address and for releasing the buffer.
*/
virtual BuffHandle allocateBuffer (BufferDescriptor const&) =0;
/** resign control of the buffer denoted by the handle */
virtual void releaseBuffer (BuffHandle&) =0;
/** declare the data contained in the Buffer to be ready.
* The caller is required to restrain itself from modifying the data
* afterwards, as this buffer now can be used (readonly) by other
* calculation processes in parallel.
*/
virtual void is_calculated (BuffHandle const&) =0;
/** generate (or calculate) an ID denoting a media data frame
* appearing at the given position in the render network,
* for the time point this rendering process is currently
* calculating data for.
* @param NodeID the unique identification of a specific node
* @param chanNo the number of the output channel of this node
* @return a complete FrameID which unambiguously denotes this
* specific frame and can be used for caching
*/
virtual FrameID const& genFrameID (NodeID const&, uint chanNo) =0;
/** try to fetch an existing buffer containing the denoted frame
* from a cache or similar backing system (e.g. network peer).
* @return either a handle to a readonly buffer, or a null handle
* @note the client is responsible for not modifying the provided data
*/
virtual BuffHandle fetch (FrameID const&) =0;
/** necessary for creating a local BuffTableChunk */
virtual BuffTableStorage& getBuffTableStorage() =0;
protected:
virtual ~State() {};
/** resolves to the State object currently "in charge".
* Intended as a performance shortcut to avoid calling
* up through a chain of virtual functions when deep down
* in chained ProcNode::pull() calls. This allows derived
* classes to proxy the state interface.
*/
virtual State& getCurrentImplementation () =0;
friend class engine::StateAdapter;
};
} // namespace engine
namespace proc_interface {
using engine::State;
} // namespace proc_interface
#endif