From 0375be1a27f8852ed8ca422db78bf6380d2b11b1 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 3 Apr 2021 21:17:27 +0300
Subject: [PATCH] Use uniform block and texture bindings from GLSL

---
 source/core/program.cpp | 46 ++++++++++++++++++++++++++++++++++-------
 source/core/program.h   |  7 +++++++
 2 files changed, 46 insertions(+), 7 deletions(-)

diff --git a/source/core/program.cpp b/source/core/program.cpp
index 999a94ad..dd38075a 100644
--- a/source/core/program.cpp
+++ b/source/core/program.cpp
@@ -3,10 +3,12 @@
 #include <msp/core/algorithm.h>
 #include <msp/core/hash.h>
 #include <msp/core/maputils.h>
+#include <msp/core/raii.h>
 #include <msp/gl/extensions/arb_es2_compatibility.h>
 #include <msp/gl/extensions/arb_fragment_shader.h>
 #include <msp/gl/extensions/arb_gl_spirv.h>
 #include <msp/gl/extensions/arb_geometry_shader4.h>
+#include <msp/gl/extensions/arb_separate_shader_objects.h>
 #include <msp/gl/extensions/arb_shader_objects.h>
 #include <msp/gl/extensions/arb_uniform_buffer_object.h>
 #include <msp/gl/extensions/arb_vertex_shader.h>
@@ -69,6 +71,7 @@ void Program::init()
 
 	id = glCreateProgram();
 	module = 0;
+	bindings = 0;
 	linked = false;
 }
 
@@ -156,6 +159,11 @@ void Program::add_glsl_stages(const GlslModule &mod, const map<string, int> &spe
 
 		compile_glsl_stage(stage_id);
 	}
+
+	if(!bindings)
+		bindings = new Bindings;
+	bindings->textures = compiler.get_texture_bindings();
+	bindings->blocks = compiler.get_uniform_block_bindings();
 }
 
 void Program::compile_glsl_stage(unsigned stage_id)
@@ -301,6 +309,34 @@ void Program::link()
 	{
 		query_uniforms();
 		query_attributes();
+		if(bindings)
+		{
+			for(unsigned i=0; i<uniform_blocks.size(); ++i)
+			{
+				map<string, unsigned>::const_iterator j = bindings->blocks.find(uniform_blocks[i].name);
+				if(j!=bindings->blocks.end())
+				{
+					glUniformBlockBinding(id, i, j->second);
+					uniform_blocks[i].bind_point = j->second;
+				}
+			}
+
+			Conditional<BindRestore> _bind(!ARB_separate_shader_objects, this);
+			for(map<string, unsigned>::const_iterator i=bindings->textures.begin(); i!=bindings->textures.end(); ++i)
+			{
+				int location = get_uniform_location(i->first);
+				if(location>=0)
+				{
+					if(ARB_separate_shader_objects)
+						glProgramUniform1i(id, location, i->second);
+					else
+						glUniform1i(location, i->second);
+				}
+			}
+
+			delete bindings;
+			bindings = 0;
+		}
 	}
 	else if(module->get_format()==Module::SPIR_V)
 	{
@@ -372,7 +408,6 @@ void Program::query_uniforms()
 
 void Program::query_uniform_blocks(const vector<UniformInfo *> &uniforms_by_index)
 {
-	std::set<unsigned> used_bind_points;
 	unsigned count = get_program_i(id, GL_ACTIVE_UNIFORM_BLOCKS);
 	// Reserve an extra index for the default block
 	uniform_blocks.reserve(count+1);
@@ -389,6 +424,9 @@ void Program::query_uniform_blocks(const vector<UniformInfo *> &uniforms_by_inde
 		glGetActiveUniformBlockiv(id, i, GL_UNIFORM_BLOCK_DATA_SIZE, &value);
 		info.data_size = value;
 
+		glGetActiveUniformBlockiv(id, i, GL_UNIFORM_BLOCK_BINDING, &value);
+		info.bind_point = value;
+
 		glGetActiveUniformBlockiv(id, i, GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS, &value);
 		vector<int> indices(value);
 		glGetActiveUniformBlockiv(id, i, GL_UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES, &indices[0]);
@@ -433,12 +471,6 @@ void Program::query_uniform_blocks(const vector<UniformInfo *> &uniforms_by_inde
 
 		sort(info.uniforms.begin(), info.uniforms.end(), uniform_location_compare);
 		info.layout_hash = compute_layout_hash(info.uniforms);
-		unsigned n_bindings = BufferRange::get_n_uniform_buffer_bindings();
-		info.bind_point = info.layout_hash%n_bindings;
-		while(used_bind_points.count(info.bind_point))
-			info.bind_point = (info.bind_point+1)%n_bindings;
-		glUniformBlockBinding(id, i, info.bind_point);
-		used_bind_points.insert(info.bind_point);
 	}
 }
 
diff --git a/source/core/program.h b/source/core/program.h
index 3af4e582..6613a134 100644
--- a/source/core/program.h
+++ b/source/core/program.h
@@ -98,9 +98,16 @@ public:
 	};
 
 private:
+	struct Bindings
+	{
+		std::map<std::string, unsigned> textures;
+		std::map<std::string, unsigned> blocks;
+	};
+
 	unsigned id;
 	std::vector<unsigned> stage_ids;
 	const Module *module;
+	Bindings *bindings;
 	bool linked;
 	std::vector<UniformBlockInfo> uniform_blocks;
 	std::vector<UniformInfo> uniforms;
-- 
2.43.0