From 4edd75061a1e24572bd672fb72e1bc1838008ce7 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 9 Sep 2013 19:06:44 +0300
Subject: [PATCH] Add interfaces for culling

Culler implementations to come soon.
---
 source/culler.h          | 25 +++++++++++++++++++++++++
 source/instancescene.cpp |  4 +++-
 source/orderedscene.cpp  |  4 +++-
 source/scene.cpp         | 29 +++++++++++++++++++++++++++++
 source/scene.h           | 11 +++++++++++
 source/simplescene.cpp   |  4 +++-
 6 files changed, 74 insertions(+), 3 deletions(-)
 create mode 100644 source/culler.h

diff --git a/source/culler.h b/source/culler.h
new file mode 100644
index 00000000..c813f8d1
--- /dev/null
+++ b/source/culler.h
@@ -0,0 +1,25 @@
+#ifndef MSP_GL_CULLER_H_
+#define MSP_GL_CULLER_H_
+
+namespace Msp {
+namespace GL {
+
+class Renderable;
+class Renderer;
+
+class Culler
+{
+protected:
+	Culler() { }
+public:
+	virtual ~Culler() { }
+
+	virtual void setup_frame(const Renderer &) { };
+
+	virtual bool cull(const Renderer &, const Renderable &) const = 0;
+};
+
+} // namespace GL
+} // namespace Msp
+
+#endif
diff --git a/source/instancescene.cpp b/source/instancescene.cpp
index 7b0979c8..0ff9b520 100644
--- a/source/instancescene.cpp
+++ b/source/instancescene.cpp
@@ -38,9 +38,11 @@ void InstanceScene::finish_frame() const
 
 void InstanceScene::render(Renderer &renderer, const Tag &tag) const
 {
+	setup_cullers(renderer);
 	for(InstanceMap::const_iterator i=renderables.begin(); i!=renderables.end(); ++i)
 		for(RenderableSet::const_iterator j=i->second.begin(); j!=i->second.end(); ++j)
-			renderer.render(**j, tag);
+			if(!cull(renderer, **j))
+				renderer.render(**j, tag);
 }
 
 } // namespace GL
diff --git a/source/orderedscene.cpp b/source/orderedscene.cpp
index e738cad7..fe968f0c 100644
--- a/source/orderedscene.cpp
+++ b/source/orderedscene.cpp
@@ -49,8 +49,10 @@ void OrderedScene::finish_frame() const
 
 void OrderedScene::render(Renderer &renderer, const Tag &tag) const
 {
+	setup_cullers(renderer);
 	for(RenderableList::const_iterator i=renderables.begin(); i!=renderables.end(); ++i)
-		renderer.render(**i, tag);
+		if(!cull(renderer, **i))
+			renderer.render(**i, tag);
 }
 
 } // namespace GL
diff --git a/source/scene.cpp b/source/scene.cpp
index d95909e9..517158f0 100644
--- a/source/scene.cpp
+++ b/source/scene.cpp
@@ -1,14 +1,43 @@
+#include "culler.h"
 #include "renderer.h"
 #include "scene.h"
 
+using namespace std;
+
 namespace Msp {
 namespace GL {
 
+void Scene::add_culler(Culler &c)
+{
+	cullers.push_back(&c);
+}
+
+void Scene::remove_culler(Culler &c)
+{
+	list<Culler *>::iterator i = find(cullers.begin(), cullers.end(), &c);
+	if(i!=cullers.end())
+		cullers.erase(i);
+}
+
 void Scene::render(const Tag &tag) const
 {
 	Renderer renderer(0);
 	render(renderer, tag);
 }
 
+void Scene::setup_cullers(const Renderer &renderer) const
+{
+	for(list<Culler *>::const_iterator i=cullers.begin(); i!=cullers.end(); ++i)
+		(*i)->setup_frame(renderer);
+}
+
+bool Scene::cull(const Renderer &renderer, const Renderable &renderable) const
+{
+	for(list<Culler *>::const_iterator i=cullers.begin(); i!=cullers.end(); ++i)
+		if((*i)->cull(renderer, renderable))
+			return true;
+	return false;
+}
+
 } // namespace GL
 } // namespace Msp
diff --git a/source/scene.h b/source/scene.h
index 19048eb3..e3aa1fab 100644
--- a/source/scene.h
+++ b/source/scene.h
@@ -6,6 +6,8 @@
 namespace Msp {
 namespace GL {
 
+class Culler;
+
 /**
 Scenes are containers for other Renderables.  This is a base class that can't
 be instantiated.  At the moment the available Scene types are SimpleScene,
@@ -14,6 +16,8 @@ InstancedScene and OrderedScene.
 class Scene: public Renderable
 {
 protected:
+	std::list<Culler *> cullers;
+
 	Scene() { }
 public:
 	virtual ~Scene() { }
@@ -21,8 +25,15 @@ public:
 	virtual void add(const Renderable &) = 0;
 	virtual void remove(const Renderable &) = 0;
 
+	void add_culler(Culler &);
+	void remove_culler(Culler &);
+
 	using Renderable::render;
 	virtual void render(const Tag & = Tag()) const;
+
+protected:
+	virtual void setup_cullers(const Renderer &) const;
+	virtual bool cull(const Renderer &, const Renderable &) const;
 };
 
 } // namespace GL
diff --git a/source/simplescene.cpp b/source/simplescene.cpp
index f866f678..c537ff3b 100644
--- a/source/simplescene.cpp
+++ b/source/simplescene.cpp
@@ -28,8 +28,10 @@ void SimpleScene::finish_frame() const
 
 void SimpleScene::render(Renderer &renderer, const Tag &tag) const
 {
+	setup_cullers(renderer);
 	for(RenderableSet::const_iterator i=renderables.begin(); i!=renderables.end(); ++i)
-		renderer.render(**i, tag);
+		if(!cull(renderer, **i))
+			renderer.render(**i, tag);
 }
 
 } // namespace GL
-- 
2.43.0