From 48b1ab4fff00c49cc15d70a354eedb3d7a2f3e87 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Thu, 28 Nov 2013 02:02:49 +0200
Subject: [PATCH] Rewrite light binding to match textures

Both have multiple multiple parallel bind points, so it makes sense they
behave in the same way.
---
 source/light.cpp     | 44 +++++++++-------------------------------
 source/light.h       |  9 +++------
 source/lightunit.cpp | 48 ++++++++++++++++++++++++++++++++++++++++++++
 source/lightunit.h   | 34 +++++++++++++++++++++++++++++++
 4 files changed, 95 insertions(+), 40 deletions(-)
 create mode 100644 source/lightunit.cpp
 create mode 100644 source/lightunit.h

diff --git a/source/light.cpp b/source/light.cpp
index 21925364..f9b45c87 100644
--- a/source/light.cpp
+++ b/source/light.cpp
@@ -1,5 +1,6 @@
 #include <stdexcept>
 #include "light.h"
+#include "lightunit.h"
 #include "misc.h"
 
 using namespace std;
@@ -7,9 +8,6 @@ using namespace std;
 namespace Msp {
 namespace GL {
 
-unsigned Light::current_unit = 0;
-vector<const Light *> Light::current_lights(1);
-
 Light::Light():
 	diffuse(1),
 	specular(1),
@@ -60,11 +58,12 @@ void Light::set_attenuation(float c, float l, float q)
 	attenuation[2] = q;
 }
 
-void Light::bind() const
+void Light::bind_to(unsigned i) const
 {
-	if(current_lights[current_unit]!=this)
+	LightUnit &unit = LightUnit::get_unit(i);
+	if(unit.set_light(this))
 	{
-		GLenum l = GL_LIGHT0+current_unit;
+		GLenum l = GL_LIGHT0+unit.get_index();
 		enable(l);
 		glLightfv(l, GL_DIFFUSE, &diffuse.r);
 		glLightfv(l, GL_SPECULAR, &specular.r);
@@ -75,42 +74,19 @@ void Light::bind() const
 		glLightf(l, GL_CONSTANT_ATTENUATION, attenuation[0]);
 		glLightf(l, GL_LINEAR_ATTENUATION, attenuation[1]);
 		glLightf(l, GL_QUADRATIC_ATTENUATION, attenuation[2]);
-		current_lights[current_unit] = this;
 	}
 }
 
-void Light::bind_to(unsigned i) const
-{
-	activate(i);
-	bind();
-}
-
-void Light::activate(unsigned i)
-{
-	static unsigned max_lights = get_i(GL_MAX_LIGHTS);
-
-	if(i>=max_lights)
-		throw out_of_range("Light::activate");
-
-	if(i>=current_lights.size())
-		current_lights.resize(i+1);
-
-	current_unit = i;
-}
-
-void Light::unbind()
+const Light *Light::current(unsigned i)
 {
-	if(current_lights[current_unit])
-	{
-		disable(GL_LIGHT0+current_unit);
-		current_lights[current_unit] = 0;
-	}
+	return LightUnit::get_unit(i).get_light();
 }
 
 void Light::unbind_from(unsigned i)
 {
-	activate(i);
-	unbind();
+	LightUnit &unit = LightUnit::get_unit(i);
+	if(unit.set_light(0))
+		disable(GL_LIGHT0+unit.get_index());
 }
 
 } // namespace GL
diff --git a/source/light.h b/source/light.h
index 658e8287..cf9ab8a1 100644
--- a/source/light.h
+++ b/source/light.h
@@ -19,9 +19,6 @@ private:
 	float spot_cutoff;
 	float attenuation[3];
 
-	static unsigned current_unit;
-	static std::vector<const Light *> current_lights;
-
 public:
 	Light();
 
@@ -41,11 +38,11 @@ public:
 	void set_attenuation(float, float, float);
 	const float *get_attenuation() const { return attenuation; }
 
-	void bind() const;
+	void bind() const { return bind_to(0); }
 	void bind_to(unsigned) const;
 
-	static void activate(unsigned);
-	static void unbind();
+	static const Light *current(unsigned = 0);
+	static void unbind() { return unbind_from(0); }
 	static void unbind_from(unsigned);
 };
 
diff --git a/source/lightunit.cpp b/source/lightunit.cpp
new file mode 100644
index 00000000..58d42e6d
--- /dev/null
+++ b/source/lightunit.cpp
@@ -0,0 +1,48 @@
+#include <stdexcept>
+#include "gl.h"
+#include "misc.h"
+#include "lightunit.h"
+
+using namespace std;
+
+namespace Msp {
+namespace GL {
+
+vector<LightUnit> LightUnit::units;
+LightUnit *LightUnit::cur_unit = 0;
+
+LightUnit::LightUnit():
+	light(0)
+{ }
+
+bool LightUnit::set_light(const Light *l)
+{
+	bool result = (l!=light);
+	light = l;
+	return result;
+}
+
+unsigned LightUnit::get_n_units()
+{
+	static int count = get_i(GL_MAX_LIGHTS);
+	return count;
+}
+
+LightUnit &LightUnit::get_unit(unsigned n)
+{
+	if(n>=get_n_units())
+		throw out_of_range("LightUnit::get_unit");
+
+	if(units.size()<=n)
+	{
+		unsigned i = units.size();
+		units.resize(n+1, LightUnit());
+		for(; i<units.size(); ++i)
+			units[i].index = i;
+	}
+
+	return units[n];
+}
+
+} // namespace GL
+} // namespace Msp
diff --git a/source/lightunit.h b/source/lightunit.h
new file mode 100644
index 00000000..3f65d770
--- /dev/null
+++ b/source/lightunit.h
@@ -0,0 +1,34 @@
+#ifndef MSP_GL_LIGHTUNIT_H_
+#define MSP_GL_LIGHTUNIT_H_
+
+#include <vector>
+
+namespace Msp {
+namespace GL {
+
+class Light;
+
+class LightUnit
+{
+private:
+	unsigned index;
+	const Light *light;
+
+	static std::vector<LightUnit> units;
+	static LightUnit *cur_unit;
+
+	LightUnit();
+
+public:
+	unsigned get_index() const { return index; }
+	bool set_light(const Light *);
+	const Light *get_light() const { return light; }
+
+	static unsigned get_n_units();
+	static LightUnit &get_unit(unsigned i);
+};
+
+} // namespace GL
+} // namespace Msp
+
+#endif
-- 
2.45.2