From 4af69ec90120a0be828a1ae475a38674087110b5 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Thu, 11 Jun 2020 14:13:38 +0300
Subject: [PATCH] Check uniforms as a hint for texunit to use for material
 textures

---
 source/material.cpp    | 11 ++++++++++-
 source/programdata.cpp |  6 ++++++
 source/programdata.h   |  1 +
 source/uniform.h       |  4 ++++
 4 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/source/material.cpp b/source/material.cpp
index 8bd6e54c..b0f62bbc 100644
--- a/source/material.cpp
+++ b/source/material.cpp
@@ -2,6 +2,7 @@
 #include "gl.h"
 #include "resources.h"
 #include "texturing.h"
+#include "uniform.h"
 
 using namespace std;
 
@@ -13,9 +14,17 @@ void Material::attach_texture_to(const Texture *tex, Texturing &texturing, Progr
 	if(!tex)
 		return;
 
-	int unit = texturing.find_free_unit(name);
+	int unit = -1;
+
+	if(const Uniform *uni = tex_shdata.find_uniform(name))
+		if(const Uniform1i *uni_int = dynamic_cast<const Uniform1i *>(uni))
+			unit = uni_int->get();
+
+	if(unit<0)
+		unit = texturing.find_free_unit(name);
 	if(unit<0)
 		throw runtime_error("no free texunit");
+
 	texturing.attach(unit, *tex);
 	tex_shdata.uniform(name, unit);
 }
diff --git a/source/programdata.cpp b/source/programdata.cpp
index 35617197..68820c59 100644
--- a/source/programdata.cpp
+++ b/source/programdata.cpp
@@ -421,6 +421,12 @@ const Uniform &ProgramData::get_uniform(const string &name) const
 	return *uniforms[i].value;
 }
 
+const Uniform *ProgramData::find_uniform(const string &name) const
+{
+	int i = find_uniform_index(name);
+	return (i>=0 ? uniforms[i].value : 0);
+}
+
 bool ProgramData::uniform_name_compare(const NamedUniform &nu, const string &name)
 {
 	return nu.name<name;
diff --git a/source/programdata.h b/source/programdata.h
index bc2289b5..c367097b 100644
--- a/source/programdata.h
+++ b/source/programdata.h
@@ -219,6 +219,7 @@ public:
 
 	std::vector<std::string> get_uniform_names() const;
 	const Uniform &get_uniform(const std::string &) const;
+	const Uniform *find_uniform(const std::string &) const;
 
 private:
 	static bool uniform_name_compare(const NamedUniform &, const std::string &);
diff --git a/source/uniform.h b/source/uniform.h
index ad2d88cc..5d288cf5 100644
--- a/source/uniform.h
+++ b/source/uniform.h
@@ -36,6 +36,8 @@ private:
 public:
 	UniformScalar(Type v): value(v) { }
 
+	Type get() const { return value; }
+
 	virtual void apply(int index) const
 	{ apply(index, 1, &value); }
 
@@ -69,6 +71,8 @@ public:
 	UniformVector(const T *vp)
 	{ std::copy(vp, vp+vecsize, value); }
 
+	BaseType get(unsigned i) const { return value[i]; }
+
 	virtual void apply(int index) const
 	{ apply(index, 1, value); }
 
-- 
2.43.0