From 765fd55bce80aa6501e7664c0c3c3ac45758bc0a Mon Sep 17 00:00:00 2001
From: Jonas Kulla <Nyocurio@gmail.com>
Date: Tue, 22 Oct 2013 06:36:13 +0200
Subject: [PATCH] Tilemap: Use simple "TexPool" replacement for atlas
 allocation

Releasing a Tilemap atlas into the pool on every map switch
will blow out tons of smaller textures for very little gain,
as atlas textures are already pretty much impossible to
recycle anywhere but in new Tilemaps.
---
 src/sharedstate.cpp | 33 +++++++++++++++++++++++++++++++++
 src/sharedstate.h   |  5 +++++
 src/tilemap.cpp     |  6 +++---
 3 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/src/sharedstate.cpp b/src/sharedstate.cpp
index d85dd1f..c79ed3a 100644
--- a/src/sharedstate.cpp
+++ b/src/sharedstate.cpp
@@ -92,6 +92,8 @@ struct SharedStatePrivate
 
 	TEXFBO gpTexFBO;
 
+	TEXFBO atlasTex;
+
 	Quad gpQuad;
 
 	unsigned int stampCounter;
@@ -143,6 +145,7 @@ struct SharedStatePrivate
 	{
 		TEX::del(globalTex);
 		TEXFBO::fini(gpTexFBO);
+		TEXFBO::fini(atlasTex);
 	}
 };
 
@@ -266,6 +269,36 @@ TEXFBO &SharedState::gpTexFBO(int minW, int minH)
 	return p->gpTexFBO;
 }
 
+void SharedState::requestAtlasTex(int w, int h, TEXFBO &out)
+{
+	TEXFBO tex;
+
+	if (w == p->atlasTex.width && h == p->atlasTex.height)
+	{
+		tex = p->atlasTex;
+		p->atlasTex = TEXFBO();
+	}
+	else
+	{
+		TEXFBO::init(tex);
+		TEXFBO::allocEmpty(tex, w, h);
+		TEXFBO::linkFBO(tex);
+	}
+
+	out = tex;
+}
+
+void SharedState::releaseAtlasTex(TEXFBO &tex)
+{
+	/* No point in caching an invalid object */
+	if (tex.tex == TEX::ID(0))
+		return;
+
+	TEXFBO::fini(p->atlasTex);
+
+	p->atlasTex = tex;
+}
+
 void SharedState::checkShutdown()
 {
 	if (!p->rtData.rqTerm)
diff --git a/src/sharedstate.h b/src/sharedstate.h
index b98c8f0..ecd2ee3 100644
--- a/src/sharedstate.h
+++ b/src/sharedstate.h
@@ -123,6 +123,11 @@ struct SharedState
 
 	Quad &gpQuad();
 
+	/* Basically just a simple "TexPool"
+	 * replacement for Tilemap atlas use */
+	void requestAtlasTex(int w, int h, TEXFBO &out);
+	void releaseAtlasTex(TEXFBO &tex);
+
 	/* Checks EventThread's shutdown request flag and if set,
 	 * requests the binding to terminate. In this case, this
 	 * function will most likely not return */
diff --git a/src/tilemap.cpp b/src/tilemap.cpp
index c9a5d83..f97a5e9 100644
--- a/src/tilemap.cpp
+++ b/src/tilemap.cpp
@@ -440,7 +440,7 @@ struct TilemapPrivate
 	{
 		destroyElements();
 
-		shState->texPool().release(atlas.gl);
+		shState->releaseAtlasTex(atlas.gl);
 		VAO::del(tiles.vao);
 		VBO::del(tiles.vbo);
 
@@ -607,8 +607,8 @@ struct TilemapPrivate
 		updateAtlasInfo();
 
 		/* Aquire atlas tex */
-		shState->texPool().release(atlas.gl);
-		atlas.gl = shState->texPool().request(atlas.size.x, atlas.size.y);
+		shState->releaseAtlasTex(atlas.gl);
+		shState->requestAtlasTex(atlas.size.x, atlas.size.y, atlas.gl);
 
 		atlasDirty = true;
 	}