-/* $Id$
-
-This file is part of libmspgl
-Copyright © 2007 Mikko Rasa, Mikkosoft Productions
-Distributed under the LGPL
-*/
-
#ifndef MSP_GL_RENDERABLE_H_
#define MSP_GL_RENDERABLE_H_
namespace Msp {
namespace GL {
+class Matrix;
+class Renderer;
+
+/**
+Base class for renderable objects. All Renderables must support rendering with
+a Renderer, and may optionally provide support for standalone rendering.
+
+The render methods take a Tag to identify a render pass. It is most commonly
+used together with Techniques and Pipelines to implement multipass rendering.
+
+The setup_frame and finish_frame methods provide a mechanism for performing
+once-per-frame operations. This is most useful for effects, which may need to
+do auxiliary rendering. With complex rendering hierarchies, these methods may
+be called multiple times for one frame, but it's guaranteed that no rendering
+will occur before a setup_frame call or after a finish_frame call.
+*/
class Renderable
{
protected:
public:
virtual ~Renderable() { }
- virtual void render(const Tag &tag = Tag()) const =0;
+ /** Returns a key used for grouping Renderables in an InstanceScene. The
+ returned value is treated as opaque. */
+ virtual long get_instance_key() const { return 0; }
+
+ /** Returns the model matrix of the Renderable. Null is returned if no such
+ matrix exists. */
+ virtual const Matrix *get_matrix() const { return 0; }
+
+ /** Called when starting to render a new frame. */
+ virtual void setup_frame() const { }
+
+ /** Called when a complete frame has been rendered. */
+ virtual void finish_frame() const { }
+
+ /** Renders the renderable without a renderer. This can be convenient in
+ some simple cases, but most renderables don't need to implement this
+ method. */
+ virtual void render(const Tag & = Tag()) const;
+
+ /** Renders the renderable. Implementors should take care to return the
+ renderer to the state it was in, for example by using Renderer::Push. */
+ virtual void render(Renderer &, const Tag & = Tag()) const = 0;
};
} // namespace Msp