From 99c6b7501afa7a712fdd61c8f1f1ecd6937a9783 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 9 Apr 2022 09:33:21 +0300
Subject: [PATCH] Refactor Renderer's texture management to make it more
 extensible

The same code can now be used for other kinds of resources as well.
---
 source/render/renderer.cpp | 55 ++++++++++++++++++++------------------
 source/render/renderer.h   | 26 ++++++++++++++----
 2 files changed, 50 insertions(+), 31 deletions(-)

diff --git a/source/render/renderer.cpp b/source/render/renderer.cpp
index 98246da7..f2fb002e 100644
--- a/source/render/renderer.cpp
+++ b/source/render/renderer.cpp
@@ -178,32 +178,36 @@ void Renderer::set_texture(Tag tag, const Texture *tex, int level, const Sampler
 	else
 		samp = 0;
 
-	if(texture_stack.size()>state.texture_count)
+	set_resource(texture_stack, state.texture_count, tag, { tex, samp, level });
+}
+
+template<typename T>
+void Renderer::set_resource(vector<BoundResource<T>> &stack, unsigned &count, Tag tag, const T &res)
+{
+	if(stack.size()>count)
 	{
-		BoundTexture &bt = texture_stack[state.texture_count];
-		if(bt.tag==tag && bt.texture==tex && bt.sampler==samp)
+		BoundResource<T> &top = stack[count];
+		if(top.tag==tag && top.resource==res)
 		{
-			++state.texture_count;
+			++count;
 			return;
 		}
 		else
-			flush_textures();
+			flush_resources(stack, count);
 	}
 
-	for(auto i=texture_stack.end(); i!=texture_stack.begin(); )
+	for(auto i=stack.end(); i!=stack.begin(); )
 		if((--i)->tag==tag)
 		{
-			i->replaced = texture_stack.size();
+			i->replaced = stack.size();
 			break;
 		}
 
-	texture_stack.emplace_back();
-	BoundTexture &bound_tex = texture_stack.back();
-	bound_tex.tag = tag;
-	bound_tex.texture = tex;
-	bound_tex.sampler = samp;
-	bound_tex.level = level;
-	state.texture_count = texture_stack.size();
+	stack.emplace_back();
+	BoundResource<T> &bound_res = stack.back();
+	bound_res.tag = tag;
+	bound_res.resource = res;
+	count = stack.size();
 }
 
 void Renderer::flush_shader_data()
@@ -214,15 +218,14 @@ void Renderer::flush_shader_data()
 		shdata_stack.erase(shdata_stack.begin()+state.shdata_count, shdata_stack.end());
 }
 
-void Renderer::flush_textures()
+template<typename T>
+void Renderer::flush_resources(vector<BoundResource<T>> &stack, unsigned &count)
 {
-	const State &state = get_state();
+	for(unsigned i=0; i<count; ++i)
+		if(stack[i].replaced>=static_cast<int>(count))
+			stack[i].replaced = -1;
 
-	for(unsigned i=0; i<state.texture_count; ++i)
-		if(texture_stack[i].replaced>=static_cast<int>(state.texture_count))
-			texture_stack[i].replaced = -1;
-
-	texture_stack.erase(texture_stack.begin()+state.texture_count, texture_stack.end());
+	stack.erase(stack.begin()+count, stack.end());
 }
 
 void Renderer::set_vertex_setup(const VertexSetup *vs)
@@ -339,7 +342,7 @@ void Renderer::apply_framebuffer()
 
 void Renderer::apply_state()
 {
-	const State &state = get_state();
+	State &state = get_state();
 
 	if(!state.shprog)
 		throw invalid_operation("Renderer::apply_state");
@@ -402,15 +405,15 @@ void Renderer::apply_state()
 	ps.set_face_cull(state.face_cull);
 
 	if(state.texture_count<texture_stack.size())
-		flush_textures();
+		flush_resources(texture_stack, state.texture_count);
 
-	for(const BoundTexture &t: texture_stack)
-		if(t.texture && t.replaced<0)
+	for(const BoundResource<SampledTexture> &t: texture_stack)
+		if(t.resource.texture && t.replaced<0)
 		{
 			if(t.binding<0 || shprog_changed)
 				t.binding = state.shprog->get_uniform_binding(t.tag);
 			if(t.binding>=0)
-				ps.set_texture(t.binding, t.texture, t.level, t.sampler);
+				ps.set_texture(t.binding, t.resource.texture, t.resource.level, t.resource.sampler);
 		}
 
 	static const DepthTest default_depth_test;
diff --git a/source/render/renderer.h b/source/render/renderer.h
index 4e702042..9335164b 100644
--- a/source/render/renderer.h
+++ b/source/render/renderer.h
@@ -63,14 +63,25 @@ public:
 	};
 
 private:
-	struct BoundTexture
+	struct SampledTexture
 	{
-		Tag tag;
-		mutable int binding = -1;
 		const Texture *texture = 0;
 		const Sampler *sampler = 0;
 		int level = -1;
+
+		SampledTexture() = default;
+		SampledTexture(const Texture *t, const Sampler *s, int l): texture(t), sampler(s), level(l) { }
+
+		bool operator==(const SampledTexture &o) const { return texture==o.texture && sampler==o.sampler && level==o.level; }
+	};
+
+	template<typename T>
+	struct BoundResource
+	{
+		Tag tag;
+		mutable int binding = -1;
 		int replaced = -1;
+		T resource;
 	};
 
 	struct BoundProgramData
@@ -115,7 +126,7 @@ private:
 	State *current_state = 0;
 	ProgramData standard_shdata;
 	std::vector<BoundProgramData> shdata_stack;
-	std::vector<BoundTexture> texture_stack;
+	std::vector<BoundResource<SampledTexture>> texture_stack;
 	const Texture &placeholder_texture;
 	const Sampler &default_sampler;
 	PipelineState *last_pipeline = 0;
@@ -188,8 +199,13 @@ public:
 	void set_texture(Tag, const Texture *, int, const Sampler * = 0);
 
 private:
+	template<typename T>
+	static void set_resource(std::vector<BoundResource<T>> &, unsigned &, Tag, const T &);
+
 	void flush_shader_data();
-	void flush_textures();
+
+	template<typename T>
+	static void flush_resources(std::vector<BoundResource<T>> &, unsigned &);
 
 public:
 	void set_vertex_setup(const VertexSetup *);
-- 
2.43.0