Lots of comment updates

[libs/gl.git] / source / renderable.h

diff --git a/source/renderable.h b/source/renderable.h
index e96ac77a853a96b9de09a30baa41096f70f3eef8..2342ae288cfed9b4d8fa61f25bf932ae47058540 100644 (file)
--- a/source/renderable.h
+++ b/source/renderable.h
@@ -1,10 +1,3 @@
-/* $Id$
-
-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_
 
@@ -14,11 +7,34 @@ Distributed under the LGPL
 namespace Msp {
 namespace GL {
 
+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.
+*/
 class Renderable
 {
+protected:
+       Renderable() { }
 public:
-       virtual bool has_pass(const Tag &tag) const =0;
-       virtual void render(const Tag &tag=Tag()) const =0;
+       virtual ~Renderable() { }
+
+       /** 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; }
+
+       /** 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