From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 25 Jan 2021 00:56:06 +0000 (+0200)
Subject: Make buffer storage immutable and use ARB_buffer_storage
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=commitdiff_plain;h=66181b3f47322ffc9b8aebf04a8c222abe1a75a2

Make buffer storage immutable and use ARB_buffer_storage
---

diff --git a/extensions/arb_buffer_storage.glext b/extensions/arb_buffer_storage.glext
new file mode 100644
index 00000000..aa03b2ad
--- /dev/null
+++ b/extensions/arb_buffer_storage.glext
@@ -0,0 +1 @@
+extension ARB_buffer_storage
diff --git a/source/buffer.cpp b/source/buffer.cpp
index 35975f17..46afb273 100644
--- a/source/buffer.cpp
+++ b/source/buffer.cpp
@@ -1,4 +1,5 @@
 #include <stdexcept>
+#include <msp/gl/extensions/arb_buffer_storage.h>
 #include <msp/gl/extensions/arb_direct_state_access.h>
 #include <msp/gl/extensions/arb_map_buffer_range.h>
 #include <msp/strings/format.h>
@@ -45,22 +46,58 @@ void Buffer::require_buffer_type(BufferType type)
 		static Require _req_ubo(ARB_uniform_buffer_object);
 }
 
+void Buffer::storage(unsigned sz)
+{
+	if(size>0)
+		throw invalid_operation("Buffer::storage");
+	if(sz==0)
+		throw invalid_argument("Buffer::storage");
+
+	size = sz;
+	if(ARB_buffer_storage)
+	{
+		static const int flags = GL_MAP_READ_BIT|GL_MAP_WRITE_BIT|GL_DYNAMIC_STORAGE_BIT;
+		if(ARB_direct_state_access)
+			glNamedBufferStorage(id, size, 0, flags);
+		else
+		{
+			BindRestore _bind(this, type);
+			glBufferStorage(type, size, 0, flags);
+		}
+	}
+}
+
 void Buffer::set_usage(BufferUsage u)
 {
 	// TODO OpenGL ES 2.0 doesn't support read or copy usages
 	usage = u;
 }
 
-void Buffer::data(unsigned sz, const void *d)
+void Buffer::data(const void *d)
 {
+	if(size==0)
+		throw invalid_operation("Buffer::data");
+
+	if(ARB_buffer_storage)
+		return sub_data(0, size, d);
+
 	if(ARB_direct_state_access)
-		glNamedBufferData(id, sz, d, usage);
+		glNamedBufferData(id, size, d, usage);
 	else
 	{
 		BindRestore _bind(this, type);
-		glBufferData(type, sz, d, usage);
+		glBufferData(type, size, d, usage);
 	}
-	size = sz;
+}
+
+void Buffer::data(unsigned sz, const void *d)
+{
+	if(size==0)
+		storage(sz);
+	else if(sz!=size)
+		throw incompatible_data("Buffer::data");
+
+	data(d);
 }
 
 void Buffer::sub_data(unsigned off, unsigned sz, const void *d)
diff --git a/source/buffer.h b/source/buffer.h
index 2961cdb3..b0f23ef2 100644
--- a/source/buffer.h
+++ b/source/buffer.h
@@ -83,16 +83,23 @@ public:
 	/** Returns the default binding type for the buffer. */
 	BufferType get_type() const { return type; }
 
+	/** Defines the storage size of the buffer.  Must be called before data can
+	be uploaded.  Storage cannot be changed once set. */
+	void storage(unsigned);
+
 	/** Sets the usage hint of the buffer.  It will take effect the next time
 	the buffer's contents are defined. */
 	DEPRECATED void set_usage(BufferUsage);
 
 	/** Uploads data into the buffer, completely replacing any previous
-	contents. */
-	void data(unsigned, const void *);
+	contents.  Storage must be defined beforehand.  The data must have size
+	matching the defined storage. */
+	void data(const void *);
+
+	DEPRECATED void data(unsigned, const void *);
 
-	/** Overwrites part of the buffer data with new data.  The buffer size can
-	not be changed with this call. */
+	/** Overwrites part of the buffer data with new data.  Storage must be
+	defined beforehand. */
 	void sub_data(unsigned, unsigned, const void *);
 
 	unsigned get_size() const { return size; }
diff --git a/source/bufferable.cpp b/source/bufferable.cpp
index fc0e3d21..4544c508 100644
--- a/source/bufferable.cpp
+++ b/source/bufferable.cpp
@@ -48,15 +48,17 @@ void Bufferable::use_buffer(Buffer *buf, Bufferable *prev)
 	update_offset();
 }
 
-void Bufferable::buffer_resized()
+void Bufferable::change_buffer(Buffer *buf)
 {
 	for(Bufferable *b=this; b; b=b->next_in_buffer)
 	{
+		b->buffer = buf;
 		b->location_dirty = true;
 		b->dirty = true;
 	}
 	for(Bufferable *b=prev_in_buffer; b; b=b->prev_in_buffer)
 	{
+		b->buffer = buf;
 		b->location_dirty = true;
 		b->dirty = true;
 	}
diff --git a/source/bufferable.h b/source/bufferable.h
index 86c5c77f..8e656246 100644
--- a/source/bufferable.h
+++ b/source/bufferable.h
@@ -45,9 +45,8 @@ public:
 	buffer, and this object is inserted after it. */
 	void use_buffer(Buffer *buf, Bufferable *prev = 0);
 
-	/** Informs the objects in this chain that the buffer has been resized and
-	data should be reuploaded. */
-	void buffer_resized();
+	/** Sets the buffer for the entire chain of objects. */
+	void change_buffer(Buffer *);
 
 	/** Returns the total amount of storage required by this object and others
 	in the same chain, including any alignment between objects. */
diff --git a/source/instancearray.cpp b/source/instancearray.cpp
index 8fead4e9..abd9fcd0 100644
--- a/source/instancearray.cpp
+++ b/source/instancearray.cpp
@@ -78,9 +78,12 @@ void InstanceArray::append(ObjectInstance *inst)
 		{
 			instance_data->append();
 			unsigned req_size = instance_data->get_required_buffer_size();
-			// XXX Inefficient, but will be rewritten imminently
-			if(instance_buffer->get_size()<req_size)
-				instance_buffer->data(req_size, 0);
+			if(instance_buffer->get_size()>0 && instance_buffer->get_size()<req_size)
+			{
+				delete instance_buffer;
+				instance_buffer = new Buffer(ARRAY_BUFFER);
+				instance_data->use_buffer(instance_buffer);
+			}
 		}
 		update_instance_matrix(instances.size()-1);
 	}
@@ -125,6 +128,8 @@ void InstanceArray::render(Renderer &renderer, const Tag &tag) const
 
 		const Mesh *mesh = object.get_mesh();
 		mesh->get_vertices().refresh();
+		if(instance_buffer->get_size()==0)
+			instance_buffer->storage(instance_data->get_required_buffer_size());
 		instance_data->refresh();
 
 		Renderer::Push push(renderer);
diff --git a/source/mesh.cpp b/source/mesh.cpp
index 3569e1c3..72936e66 100644
--- a/source/mesh.cpp
+++ b/source/mesh.cpp
@@ -54,35 +54,28 @@ void Mesh::check_buffers(unsigned mask)
 {
 	if(mask&VERTEX_BUFFER)
 	{
-		if(!vbuf)
+		unsigned req_size = vertices.get_required_buffer_size();
+		if(!vbuf || (vbuf->get_size()>0 && vbuf->get_size()<req_size))
 		{
+			delete vbuf;
 			vbuf = new Buffer(ARRAY_BUFFER);
 			vertices.use_buffer(vbuf);
 			vtx_setup.set_vertex_array(vertices);
-		}
-		unsigned req_size = vertices.get_required_buffer_size();
-		if(vbuf->get_size()<req_size)
-		{
 			dirty |= VERTEX_BUFFER;
-			vertices.buffer_resized();
 		}
 	}
 
 	if(mask&INDEX_BUFFER)
 	{
-		if(!ibuf)
+		unsigned req_size = (batches.empty() ? 0 : batches.front().get_required_buffer_size());
+		if(!ibuf || (ibuf->get_size()>0 && ibuf->get_size()<req_size))
 		{
+			delete ibuf;
 			ibuf = new Buffer(ELEMENT_ARRAY_BUFFER);
 			if(!batches.empty())
-				batches.front().use_buffer(ibuf);
+				batches.front().change_buffer(ibuf);
 			vtx_setup.set_index_buffer(*ibuf);
-		}
-		unsigned req_size = (batches.empty() ? 0 : batches.front().get_required_buffer_size());
-		if(ibuf->get_size()<req_size)
-		{
 			dirty |= INDEX_BUFFER;
-			if(!batches.empty())
-				batches.front().buffer_resized();
 		}
 	}
 }
@@ -182,9 +175,9 @@ void Mesh::draw(Renderer &renderer, const VertexSetup *vs, unsigned count) const
 void Mesh::resize_buffers() const
 {
 	if(dirty&VERTEX_BUFFER)
-		vbuf->data(vertices.get_required_buffer_size(), 0);
+		vbuf->storage(vertices.get_required_buffer_size());
 	if(dirty&INDEX_BUFFER)
-		ibuf->data(batches.front().get_required_buffer_size(), 0);
+		ibuf->storage(batches.front().get_required_buffer_size());
 	dirty = 0;
 }
 
diff --git a/source/programdata.cpp b/source/programdata.cpp
index 1589d9b0..4a6c262a 100644
--- a/source/programdata.cpp
+++ b/source/programdata.cpp
@@ -603,7 +603,16 @@ void ProgramData::apply() const
 		{
 			unsigned required_size = last_block->get_required_buffer_size();
 			if(last_block->get_required_buffer_size()>buffer->get_size())
-				buffer->data(required_size, 0);
+			{
+				if(buffer->get_size()>0)
+				{
+					delete buffer;
+					buffer = new Buffer(UNIFORM_BUFFER);
+					last_block->change_buffer(buffer);
+				}
+
+				buffer->storage(required_size);
+			}
 		}
 	}