X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=blobdiff_plain;f=source%2Frenderable.h;h=6e1505ca5a728c0ac1b012eb797cf00c84321ff4;hp=78879a3d8030fb15fcd41136c16ec7c831541972;hb=133fe7352831197c9ec59f923c1126651d80edcb;hpb=18878df418035445ba5146fcde3d647d7aa8c054

diff --git a/source/renderable.h b/source/renderable.h
index 78879a3d..6e1505ca 100644
--- a/source/renderable.h
+++ b/source/renderable.h
@@ -2,16 +2,28 @@
 #define MSP_GL_RENDERABLE_H_
 
 #include <string>
+#include <msp/geometry/boundingsphere.h>
 #include "tag.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.
+Base class for renderable objects.  Rendering is performed with the help of a
+Renderer object.
+
+The render method takes a Tag to identify a render pass.  It can be used with
+a Technique to select alternative rendering methods, such as simplified shaders
+for a depth-only shadow pass.
+
+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
 {
@@ -20,10 +32,28 @@ protected:
 public:
 	virtual ~Renderable() { }
 
-	/** Returns a key used for grouping Renderables in an InstanceScene. */
+	/** 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; }
 
-	virtual void render(const Tag & = Tag()) const;
+	/** Returns the model matrix of the Renderable.  Null is returned if no such
+	matrix exists.  The matrix should be in world space for some effects to work
+	correctly. */
+	virtual const Matrix *get_matrix() const { return 0; }
+
+	/** Returns a bounding sphere that completely encloses the Renderable.  The
+	bounding sphere is expressed in the renderable's coordinates.  Null is
+	returned if the bounding sphere cannot be determined. */
+	virtual const Geometry::BoundingSphere<float, 3> *get_bounding_sphere() const { return 0; }
+
+	/** Called when starting to render a new frame. */
+	virtual void setup_frame(Renderer &) { }
+
+	/** Called when a complete frame has been rendered. */
+	virtual void finish_frame() { }
+
+	/** 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;
 };