From: Mikko Rasa <tdb@tdb.fi>
Date: Thu, 18 Nov 2021 10:09:57 +0000 (+0200)
Subject: Refactor low-level state management
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=a6d84d93ce8c0adde41679a6c6852335e19ada17;p=libs%2Fgl.git

Refactor low-level state management

The global context state is now held in Device.

The changes mask in PipelineState was also moved to the backend class,
because pipeline state is applied very differently in Vulkan.
---

diff --git a/source/backends/opengl/buffer_backend.cpp b/source/backends/opengl/buffer_backend.cpp
index e0f5525a..13944a86 100644
--- a/source/backends/opengl/buffer_backend.cpp
+++ b/source/backends/opengl/buffer_backend.cpp
@@ -6,14 +6,13 @@
 #include <msp/gl/extensions/oes_mapbuffer.h>
 #include "buffer.h"
 #include "buffer_backend.h"
+#include "device.h"
 
 using namespace std;
 
 namespace Msp {
 namespace GL {
 
-OpenGLBuffer *OpenGLBuffer::scratch_binding = 0;
-
 OpenGLBuffer::OpenGLBuffer()
 {
 	static Require _req(ARB_vertex_buffer_object);
@@ -32,7 +31,7 @@ OpenGLBuffer::OpenGLBuffer(OpenGLBuffer &&other):
 
 OpenGLBuffer::~OpenGLBuffer()
 {
-	if(this==scratch_binding)
+	if(this==Device::get_current().get_state().scratch_buffer)
 		unbind_scratch();
 	if(id)
 		glDeleteBuffers(1, &id);
@@ -115,6 +114,7 @@ void OpenGLBuffer::set_debug_name(const string &name)
 
 void OpenGLBuffer::bind_scratch()
 {
+	const OpenGLBuffer *&scratch_binding = Device::get_current().get_state().scratch_buffer;
 	if(scratch_binding!=this)
 	{
 		glBindBuffer(GL_ARRAY_BUFFER, id);
@@ -124,6 +124,7 @@ void OpenGLBuffer::bind_scratch()
 
 void OpenGLBuffer::unbind_scratch()
 {
+	const OpenGLBuffer *&scratch_binding = Device::get_current().get_state().scratch_buffer;
 	if(scratch_binding)
 	{
 		glBindBuffer(GL_ARRAY_BUFFER, 0);
diff --git a/source/backends/opengl/buffer_backend.h b/source/backends/opengl/buffer_backend.h
index 6595ec2a..3d76c01a 100644
--- a/source/backends/opengl/buffer_backend.h
+++ b/source/backends/opengl/buffer_backend.h
@@ -15,8 +15,6 @@ class OpenGLBuffer: public NonCopyable
 protected:
 	unsigned id = 0;
 
-	static OpenGLBuffer *scratch_binding;
-
 	OpenGLBuffer();
 	OpenGLBuffer(OpenGLBuffer &&);
 	~OpenGLBuffer();
diff --git a/source/backends/opengl/device_backend.cpp b/source/backends/opengl/device_backend.cpp
index 35c0ca5c..7819c98f 100644
--- a/source/backends/opengl/device_backend.cpp
+++ b/source/backends/opengl/device_backend.cpp
@@ -87,6 +87,9 @@ void OpenGLDevice::fill_info()
 	feat.ext_texture_array = EXT_texture_array;
 	feat.uniform_binding_range = lim.max_uniform_bindings;
 	feat.texture_binding_range = lim.max_texture_bindings;
+
+	state.bound_tex_targets.resize(lim.max_texture_bindings);
+	state.bound_uniform_blocks.resize(lim.max_uniform_bindings);
 }
 
 } // namespace GL
diff --git a/source/backends/opengl/device_backend.h b/source/backends/opengl/device_backend.h
index dfa16653..491f1b31 100644
--- a/source/backends/opengl/device_backend.h
+++ b/source/backends/opengl/device_backend.h
@@ -1,16 +1,33 @@
 #ifndef MSP_GL_DEVICE_BACKEND_H_
 #define MSP_GL_DEVICE_BACKEND_H_
 
+#include <vector>
 #include <msp/core/noncopyable.h>
 #include <msp/graphics/glcontext.h>
 
 namespace Msp {
 namespace GL {
 
+class OpenGLBuffer;
+class OpenGLPipelineState;
+class OpenGLTexture;
+
+struct OpenGLDeviceState
+{
+	const OpenGLPipelineState *last_pipeline = 0;
+	std::vector<int> bound_tex_targets;
+	std::vector<char> bound_uniform_blocks;
+	unsigned restart_index = 0;
+	unsigned n_clip_distances = 0;
+	const OpenGLBuffer *scratch_buffer = 0;
+	const OpenGLTexture *scratch_texture = 0;
+};
+
 class OpenGLDevice: public NonCopyable
 {
 protected:
 	Graphics::GLContext context;
+	OpenGLDeviceState state;
 
 	OpenGLDevice(Graphics::Window &, const Graphics::GLOptions &);
 
@@ -19,6 +36,9 @@ protected:
 	void fill_info();
 
 	Graphics::GLContext &get_context() { return context; }
+
+public:
+	OpenGLDeviceState &get_state() { return state; }
 };
 
 using DeviceBackend = OpenGLDevice;
diff --git a/source/backends/opengl/pipelinestate_backend.cpp b/source/backends/opengl/pipelinestate_backend.cpp
index 19ee0f58..9616b18b 100644
--- a/source/backends/opengl/pipelinestate_backend.cpp
+++ b/source/backends/opengl/pipelinestate_backend.cpp
@@ -26,37 +26,34 @@ using namespace std;
 namespace Msp {
 namespace GL {
 
-const OpenGLPipelineState *OpenGLPipelineState::last_applied = 0;
-vector<int> OpenGLPipelineState::bound_tex_targets;
-vector<char> OpenGLPipelineState::bound_uniform_blocks;
-unsigned OpenGLPipelineState::restart_index = 0;
-unsigned OpenGLPipelineState::n_clip_distances = 0;
-
-OpenGLPipelineState::OpenGLPipelineState()
-{
-	if(bound_tex_targets.empty())
-		bound_tex_targets.resize(Device::get_current().get_info().limits.max_texture_bindings);
-	if(bound_uniform_blocks.empty())
-		bound_uniform_blocks.resize(Device::get_current().get_info().limits.max_uniform_bindings);
-}
-
 OpenGLPipelineState::~OpenGLPipelineState()
 {
-	if(this==last_applied)
-		last_applied = 0;
+	if(applied_to)
+		applied_to->get_state().last_pipeline = 0;
 }
 
 void OpenGLPipelineState::apply() const
 {
-	if(!last_applied)
-		OpenGLTexture::unbind_scratch();
+	const PipelineState &self = *static_cast<const PipelineState *>(this);
+	Device &device = Device::get_current();
+	unsigned mask = changes;
 
-	apply(this==last_applied ? static_cast<const PipelineState *>(this)->changes : ~0U);
-}
+	if(applied_to && applied_to!=&device)
+	{
+		applied_to->get_state().last_pipeline = 0;
+		mask = ~0U;
+	}
 
-void OpenGLPipelineState::apply(unsigned mask) const
-{
-	const PipelineState &self = *static_cast<const PipelineState *>(this);
+	OpenGLDeviceState &dev_state = device.get_state();
+	if(!dev_state.last_pipeline)
+		OpenGLTexture::unbind_scratch();
+	
+	if(this!=dev_state.last_pipeline)
+	{
+		if(dev_state.last_pipeline)
+			dev_state.last_pipeline->applied_to = 0;
+		mask = ~0U;
+	}
 
 	if(mask&PipelineState::FRAMEBUFFER)
 	{
@@ -93,16 +90,16 @@ void OpenGLPipelineState::apply(unsigned mask) const
 		glUseProgram(self.shprog ? self.shprog->id : 0);
 
 		unsigned ncd = (self.shprog ? self.shprog->get_n_clip_distances() : 0);
-		if(ncd!=n_clip_distances)
+		if(ncd!=dev_state.n_clip_distances)
 		{
-			for(unsigned i=0; (i<ncd || i<n_clip_distances); ++i)
+			for(unsigned i=0; (i<ncd || i<dev_state.n_clip_distances); ++i)
 			{
 				if(i<ncd)
 					glEnable(GL_CLIP_PLANE0+i);
 				else
 					glDisable(GL_CLIP_PLANE0+i);
 			}
-			n_clip_distances = ncd;
+			dev_state.n_clip_distances = ncd;
 		}
 	}
 
@@ -116,7 +113,7 @@ void OpenGLPipelineState::apply(unsigned mask) const
 					if(u.binding>=0)
 					{
 						glBindBufferRange(GL_UNIFORM_BUFFER, u.binding, u.block->get_buffer()->id, u.block->get_offset(), u.block->get_data_size());
-						bound_uniform_blocks[u.binding] = 1;
+						dev_state.bound_uniform_blocks[u.binding] = 1;
 					}
 					else if(u.binding==ReflectData::DEFAULT_BLOCK && self.shprog)
 					{
@@ -142,12 +139,12 @@ void OpenGLPipelineState::apply(unsigned mask) const
 					else
 					{
 						glActiveTexture(GL_TEXTURE0+t.binding);
-						if(bound_tex_targets[t.binding] && static_cast<int>(t.texture->target)!=bound_tex_targets[t.binding])
-							glBindTexture(bound_tex_targets[t.binding], 0);
+						if(dev_state.bound_tex_targets[t.binding] && static_cast<int>(t.texture->target)!=dev_state.bound_tex_targets[t.binding])
+							glBindTexture(dev_state.bound_tex_targets[t.binding], 0);
 						glBindTexture(t.texture->target, t.texture->id);
 					}
 
-					bound_tex_targets[t.binding] = t.texture->target;
+					dev_state.bound_tex_targets[t.binding] = t.texture->target;
 
 					glBindSampler(t.binding, t.sampler->id);
 					t.sampler->refresh();
@@ -167,12 +164,12 @@ void OpenGLPipelineState::apply(unsigned mask) const
 
 			vertex_setup->refresh();
 			unsigned ri = (vertex_setup->get_index_type()==UNSIGNED_INT ? 0xFFFFFFFF : 0xFFFF);
-			if(ri!=restart_index)
+			if(ri!=dev_state.restart_index)
 			{
-				if(!restart_index)
+				if(!dev_state.restart_index)
 					glEnable(GL_PRIMITIVE_RESTART);
 				glPrimitiveRestartIndex(ri);
-				restart_index = ri;
+				dev_state.restart_index = ri;
 			}
 		}
 	}
@@ -236,39 +233,41 @@ void OpenGLPipelineState::apply(unsigned mask) const
 		}
 	}
 
-	last_applied = this;
-	self.changes &= ~mask;
+	applied_to = &device;
+	dev_state.last_pipeline = this;
+	changes = 0;
 }
 
 void OpenGLPipelineState::clear()
 {
-	if(last_applied)
+	OpenGLDeviceState &dev_state = Device::get_current().get_state();
+	if(dev_state.last_pipeline)
 	{
 		glUseProgram(0);
 		glBindVertexArray(0);
 
-		for(unsigned i=0; i<n_clip_distances; ++i)
+		for(unsigned i=0; i<dev_state.n_clip_distances; ++i)
 			glDisable(GL_CLIP_PLANE0+i);
-		n_clip_distances = 0;
+		dev_state.n_clip_distances = 0;
 
-		for(unsigned i=0; i<bound_tex_targets.size(); ++i)
-			if(bound_tex_targets[i])
+		for(unsigned i=0; i<dev_state.bound_tex_targets.size(); ++i)
+			if(dev_state.bound_tex_targets[i])
 			{
 				if(ARB_direct_state_access)
 					glBindTextureUnit(i, 0);
 				else
 				{
 					glActiveTexture(GL_TEXTURE0+i);
-					glBindTexture(bound_tex_targets[i], 0);
+					glBindTexture(dev_state.bound_tex_targets[i], 0);
 				}
-				bound_tex_targets[i] = 0;
+				dev_state.bound_tex_targets[i] = 0;
 			}
 
-		for(unsigned i=0; i<bound_uniform_blocks.size(); ++i)
-			if(bound_uniform_blocks[i])
+		for(unsigned i=0; i<dev_state.bound_uniform_blocks.size(); ++i)
+			if(dev_state.bound_uniform_blocks[i])
 			{
 				glBindBufferBase(GL_UNIFORM_BUFFER, i, 0);
-				bound_uniform_blocks[i] = 0;
+				dev_state.bound_uniform_blocks[i] = 0;
 			}
 
 		glDisable(GL_DEPTH_TEST);
@@ -276,7 +275,8 @@ void OpenGLPipelineState::clear()
 		glDisable(GL_STENCIL_TEST);
 		glDisable(GL_BLEND);
 
-		last_applied = 0;
+		dev_state.last_pipeline->applied_to = 0;
+		dev_state.last_pipeline = 0;
 	}
 }
 
diff --git a/source/backends/opengl/pipelinestate_backend.h b/source/backends/opengl/pipelinestate_backend.h
index 566b819c..a8f2d306 100644
--- a/source/backends/opengl/pipelinestate_backend.h
+++ b/source/backends/opengl/pipelinestate_backend.h
@@ -7,25 +7,22 @@
 namespace Msp {
 namespace GL {
 
+class Device;
+
 class OpenGLPipelineState: public NonCopyable
 {
 	friend class OpenGLCommands;
 
 protected:
-	static const OpenGLPipelineState *last_applied;
-	static std::vector<int> bound_tex_targets;
-	static std::vector<char> bound_uniform_blocks;
-	static unsigned restart_index;
-	static unsigned n_clip_distances;
+	mutable Device *applied_to = 0;
+	mutable unsigned changes = 0;
 
-	OpenGLPipelineState();
+	OpenGLPipelineState() = default;
 	OpenGLPipelineState(OpenGLPipelineState &&) { }
 	~OpenGLPipelineState();
 
 	void apply() const;
-private:
-	void apply(unsigned) const;
-protected:
+
 	static void clear();
 };
 
diff --git a/source/backends/opengl/texture_backend.cpp b/source/backends/opengl/texture_backend.cpp
index ebfeb025..818defdd 100644
--- a/source/backends/opengl/texture_backend.cpp
+++ b/source/backends/opengl/texture_backend.cpp
@@ -2,6 +2,7 @@
 #include <msp/gl/extensions/arb_texture_swizzle.h>
 #include <msp/gl/extensions/ext_framebuffer_object.h>
 #include <msp/gl/extensions/khr_debug.h>
+#include "device.h"
 #include "gl.h"
 #include "error.h"
 #include "texture.h"
@@ -12,8 +13,6 @@ using namespace std;
 namespace Msp {
 namespace GL {
 
-OpenGLTexture *OpenGLTexture::scratch_binding = 0;
-
 OpenGLTexture::OpenGLTexture(unsigned t):
 	target(t)
 {
@@ -35,7 +34,7 @@ OpenGLTexture::OpenGLTexture(OpenGLTexture &&other):
 
 OpenGLTexture::~OpenGLTexture()
 {
-	if(this==scratch_binding)
+	if(this==Device::get_current().get_state().scratch_texture)
 		unbind_scratch();
 	if(id)
 		glDeleteTextures(1, &id);
@@ -119,6 +118,7 @@ void OpenGLTexture::set_debug_name(const string &name)
 
 void OpenGLTexture::bind_scratch()
 {
+	const OpenGLTexture *&scratch_binding = Device::get_current().get_state().scratch_texture;
 	if(!scratch_binding)
 		glActiveTexture(GL_TEXTURE0);
 	if(scratch_binding!=this)
@@ -132,6 +132,7 @@ void OpenGLTexture::bind_scratch()
 
 void OpenGLTexture::unbind_scratch()
 {
+	const OpenGLTexture *&scratch_binding = Device::get_current().get_state().scratch_texture;
 	if(scratch_binding)
 	{
 		glBindTexture(scratch_binding->target, 0);
diff --git a/source/backends/opengl/texture_backend.h b/source/backends/opengl/texture_backend.h
index ecb3056f..623bd813 100644
--- a/source/backends/opengl/texture_backend.h
+++ b/source/backends/opengl/texture_backend.h
@@ -16,8 +16,6 @@ protected:
 	unsigned target;
 	std::string debug_name;
 
-	static OpenGLTexture *scratch_binding;
-
 	OpenGLTexture(unsigned);
 	OpenGLTexture(OpenGLTexture &&);
 	~OpenGLTexture();
diff --git a/source/core/pipelinestate.h b/source/core/pipelinestate.h
index 0973bfb5..5e593309 100644
--- a/source/core/pipelinestate.h
+++ b/source/core/pipelinestate.h
@@ -79,7 +79,6 @@ private:
 	const DepthTest *depth_test = 0;
 	const StencilTest *stencil_test = 0;
 	const Blend *blend = 0;
-	mutable unsigned changes = 0;
 
 	template<typename T>
 	void set(T &, T, unsigned);