From a8383f1163cd020e2ce2c030e93defd2f9909a1d Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 17 Apr 2021 21:43:48 +0300
Subject: [PATCH] Don't use an index when attaching lights

It's a relic of legacy OpenGL's way of doing lighting and unnecessary
in a modern engine.
---
 source/materials/lighting.cpp | 28 +++++++++++++++++++++-------
 source/materials/lighting.h   | 19 +++++++++++++------
 tools/viewer.cpp              |  2 +-
 3 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/source/materials/lighting.cpp b/source/materials/lighting.cpp
index fa0c26b4..bcf2bb0e 100644
--- a/source/materials/lighting.cpp
+++ b/source/materials/lighting.cpp
@@ -1,5 +1,6 @@
 #include <stdexcept>
 #include <cmath>
+#include <msp/core/algorithm.h>
 #include "error.h"
 #include "light.h"
 #include "lighting.h"
@@ -63,12 +64,17 @@ void Lighting::set_fog_half_distance(float d)
 	set_fog_density(-log(pow(0.5, 1.0/d)));
 }
 
-void Lighting::attach(unsigned i, const Light &l)
+void Lighting::attach(const Light &l)
 {
-	if(i>=lights.size())
-		lights.resize(i+1);
+	if(find(lights, &l)==lights.end())
+		lights.push_back(&l);
+}
 
-	lights[i] = &l;
+void Lighting::detach(const Light &l)
+{
+	vector<const Light *>::iterator i = find(lights, &l);
+	if(i!=lights.end())
+		lights.erase(i);
 }
 
 void Lighting::detach(unsigned i)
@@ -76,7 +82,7 @@ void Lighting::detach(unsigned i)
 	if(i>=lights.size())
 		return;
 
-	lights[i] = 0;
+	detach(*lights[i]);
 }
 
 const Light *Lighting::get_attached_light(unsigned i) const
@@ -120,6 +126,9 @@ void Lighting::Loader::init_actions()
 	add("light", &Loader::light);
 	add("sky_color", &Loader::sky_color);
 	add("zenith_direction", &Loader::zenith_direction);
+
+	// Deprecated
+	add("light", &Loader::light_index);
 }
 
 void Lighting::Loader::ambient(float r, float g, float b)
@@ -147,14 +156,19 @@ void Lighting::Loader::horizon_angle(float a)
 	obj.set_horizon_angle(Geometry::Angle<float>::from_degrees(a));
 }
 
-void Lighting::Loader::light(unsigned i)
+void Lighting::Loader::light()
 {
 	RefPtr<Light> lgt = new Light;
 	load_sub(*lgt);
-	obj.attach(i, *lgt);
+	obj.attach(*lgt);
 	obj.owned_data.push_back(lgt.release());
 }
 
+void Lighting::Loader::light_index(unsigned)
+{
+	light_inline();
+}
+
 void Lighting::Loader::sky_color(float r, float g, float b)
 {
 	obj.set_sky_color(Color(r, g, b));
diff --git a/source/materials/lighting.h b/source/materials/lighting.h
index 56c728a1..226dee1c 100644
--- a/source/materials/lighting.h
+++ b/source/materials/lighting.h
@@ -35,7 +35,8 @@ public:
 		void fog_density(float);
 		void fog_half_distance(float);
 		void horizon_angle(float);
-		void light(unsigned);
+		void light();
+		void light_index(unsigned);
 		void sky_color(float, float, float);
 		void zenith_direction(float, float, float);
 	};
@@ -80,15 +81,21 @@ public:
 	distance is 50%. */
 	void set_fog_half_distance(float);
 
-	/** Attaches a light source. */
-	void attach(unsigned, const Light &);
+	/** Attaches a light source.  If the light was already attached, does
+	nothing. */
+	void attach(const Light &);
 
-	/** Detaches a light source. */
-	void detach(unsigned);
+	/** Detaches a light source.  If the light was not attached, does nothing. */
+	void detach(const Light &);
+
+	DEPRECATED void attach(unsigned, const Light &l) { attach(l); }
+	DEPRECATED void detach(unsigned);
 
 	/** Returns an attached light.  If no light is attached at that index, null
 	is returned. */
-	const Light *get_attached_light(unsigned) const;
+	DEPRECATED const Light *get_attached_light(unsigned) const;
+
+	const std::vector<const Light *> &get_attached_lights() const { return lights; }
 
 	/** Updates a ProgramData object with the uniforms for the Lighting,
 	including all attached light sources.  A view matrix must be passed in. */
diff --git a/tools/viewer.cpp b/tools/viewer.cpp
index 674fbf16..e7af7024 100644
--- a/tools/viewer.cpp
+++ b/tools/viewer.cpp
@@ -215,7 +215,7 @@ Viewer::Viewer(int argc, char **argv):
 	mouse.signal_axis_motion.connect(sigc::bind_return(sigc::mem_fun(this, &Viewer::axis_motion), false));
 
 	light.set_position(GL::Vector4(0, 0, 1, 0));
-	lighting.attach(0, light);
+	lighting.attach(light);
 
 	camera.set_up_direction(GL::Vector3(0, 0, 1));
 	update_camera();
-- 
2.43.0