From 126ac7ca4053b765eab1473d2865bce728ef2428 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 22 Dec 2013 02:15:06 +0200
Subject: [PATCH] Simplify VAO setup code

Previously buffer binding semantics caused complications, as index buffer
was unbound while a mesh was bound so batches couldn't be updated.  Now
that buffers behave better with bounds meshes, batches can take care of
themselves again.

Triggering the setup from bind() instead of draw() gets rid of another
bunch of complications, since it will only be called when the VAO is going
to be actually used.
---
 source/mesh.cpp | 76 ++++++++++++++++++-------------------------------
 source/mesh.h   |  4 +--
 2 files changed, 29 insertions(+), 51 deletions(-)

diff --git a/source/mesh.cpp b/source/mesh.cpp
index 45b022fa..45c550a0 100644
--- a/source/mesh.cpp
+++ b/source/mesh.cpp
@@ -16,7 +16,7 @@ Mesh::Mesh():
 	ibuf(0),
 	vao_id(0),
 	defer_buffers(true),
-	dirty(0),
+	dirty(false),
 	winding(0)
 { }
 
@@ -26,7 +26,7 @@ Mesh::Mesh(const VertexFormat &f):
 	ibuf(0),
 	vao_id(0),
 	defer_buffers(true),
-	dirty(2),
+	dirty(true),
 	winding(0)
 { }
 
@@ -74,52 +74,29 @@ void Mesh::create_buffers()
 		glGenVertexArrays(1, &vao_id);
 }
 
-void Mesh::refresh() const
+void Mesh::setup_vao() const
 {
-	if(!vbuf)
-		return;
+	Bind bind_vbuf(vbuf, ARRAY_BUFFER);
 
-	vertices.refresh();
-	if(dirty)
+	const VertexFormat &fmt = vertices.get_format();
+	unsigned stride = get_stride(fmt)*sizeof(float);
+	float *ptr = 0;
+	for(const unsigned char *c=fmt.begin(); c!=fmt.end(); ++c)
 	{
-		if(dirty&1)
-		{
-			for(list<Batch>::const_iterator i=batches.begin(); i!=batches.end(); ++i)
-				i->refresh();
-		}
-
-		if(dirty&2)
-		{
-			Bind bind_vbuf(vbuf, ARRAY_BUFFER);
-
-			bool bind_here = !current();
-			if(bind_here)
-				glBindVertexArray(vao_id);
-
-			const VertexFormat &fmt = vertices.get_format();
-			unsigned stride = get_stride(fmt)*sizeof(float);
-			float *ptr = 0;
-			for(const unsigned char *c=fmt.begin(); c!=fmt.end(); ++c)
-			{
-				unsigned t = get_component_type(*c);
-				if(t>=get_component_type(ATTRIB1))
-					t -= get_component_type(ATTRIB1);
-				unsigned sz = get_component_size(*c);
-				if(*c==COLOR4_UBYTE)
-					glVertexAttribPointer(t, 4, GL_UNSIGNED_BYTE, true, stride, ptr);
-				else
-					glVertexAttribPointer(t, sz, GL_FLOAT, false, stride, ptr);
-				glEnableVertexAttribArray(t);
-				ptr += sz;
-			}
-			glBindBuffer(ELEMENT_ARRAY_BUFFER, ibuf->get_id());
-
-			if(bind_here)
-				glBindVertexArray(0);
-		}
-
-		dirty = 0;
+		unsigned t = get_component_type(*c);
+		if(t>=get_component_type(ATTRIB1))
+			t -= get_component_type(ATTRIB1);
+		unsigned sz = get_component_size(*c);
+		if(*c==COLOR4_UBYTE)
+			glVertexAttribPointer(t, 4, GL_UNSIGNED_BYTE, true, stride, ptr);
+		else
+			glVertexAttribPointer(t, sz, GL_FLOAT, false, stride, ptr);
+		glEnableVertexAttribArray(t);
+		ptr += sz;
 	}
+	glBindBuffer(ELEMENT_ARRAY_BUFFER, ibuf->get_id());
+
+	dirty = false;
 }
 
 unsigned Mesh::get_n_vertices() const
@@ -160,8 +137,6 @@ void Mesh::draw() const
 	if(cur && cur!=this)
 		throw invalid_operation("Mesh::draw");
 
-	refresh();
-
 	if(!current())
 		vertices.apply();
 	Bind bind_ibuf(ibuf, ELEMENT_ARRAY_BUFFER);
@@ -173,8 +148,6 @@ void Mesh::draw() const
 
 void Mesh::draw(Renderer &renderer) const
 {
-	refresh();
-
 	renderer.set_mesh(this);
 	renderer.set_element_buffer(ibuf);
 	renderer.set_winding_test(winding);
@@ -190,7 +163,12 @@ void Mesh::bind() const
 	if(!vao_id)
 		unbind();
 	else if(set_current(this))
+	{
 		glBindVertexArray(vao_id);
+		vertices.refresh();
+		if(dirty)
+			setup_vao();
+	}
 }
 
 void Mesh::unbind()
@@ -217,7 +195,7 @@ void Mesh::Loader::vertices(const vector<VertexComponent> &c)
 	for(vector<VertexComponent>::const_iterator i=c.begin(); i!=c.end(); ++i)
 		fmt = (fmt, *i);
 	obj.vertices.reset(fmt);
-	obj.dirty |= 2;
+	obj.dirty = true;
 	load_sub(obj.vertices);
 }
 
diff --git a/source/mesh.h b/source/mesh.h
index ba21f256..730b724c 100644
--- a/source/mesh.h
+++ b/source/mesh.h
@@ -39,7 +39,7 @@ private:
 	Buffer *ibuf;
 	unsigned vao_id;
 	bool defer_buffers;
-	mutable unsigned char dirty;
+	mutable bool dirty;
 	const WindingTest *winding;
 
 public:
@@ -51,7 +51,7 @@ public:
 	void use_buffers(bool);
 private:
 	void create_buffers();
-	void refresh() const;
+	void setup_vao() const;
 
 public:
 	const VertexArray &get_vertices() const { return vertices; }
-- 
2.45.2