From 74c0467f6b55fad6ab9b5000d66338307ab7b4a7 Mon Sep 17 00:00:00 2001
From: Rebmiami <59275598+Rebmiami@users.noreply.github.com>
Date: Mon, 11 Dec 2023 08:48:12 -0500
Subject: [PATCH] Basic burning properties

---
 src/simulation/elements/FIRE.cpp |  5 +++
 src/simulation/elements/PAPR.cpp | 58 +++++++++++++++++++-------------
 2 files changed, 40 insertions(+), 23 deletions(-)

diff --git a/src/simulation/elements/FIRE.cpp b/src/simulation/elements/FIRE.cpp
index 69d2b3fd2..59c243a97 100644
--- a/src/simulation/elements/FIRE.cpp
+++ b/src/simulation/elements/FIRE.cpp
@@ -195,6 +195,11 @@ int Element_FIRE_update(UPDATE_FUNC_ARGS)
 						}
 					}
 				}
+				// Make paper burn more reliably
+				if (rt==PT_PAPR)
+				{
+					parts[ID(r)].temp += 4;
+				}
 
 				if (t == PT_LAVA)
 				{
diff --git a/src/simulation/elements/PAPR.cpp b/src/simulation/elements/PAPR.cpp
index b7ef6e17c..4a9892f5d 100644
--- a/src/simulation/elements/PAPR.cpp
+++ b/src/simulation/elements/PAPR.cpp
@@ -3,6 +3,15 @@
 static int update(UPDATE_FUNC_ARGS);
 static int graphics(GRAPHICS_FUNC_ARGS);
 
+// Element overview:
+// PAPR (Paper) is a flammable solid element that can be colored by certain other elements.
+// Additionally, it can be read and written to by ARAY.
+
+// Property usage:
+// life: Temporary read/write state for ARAY interaction
+// tmp: Written color value. If dcolour is not black, it gets copied here. 1 bit alpha
+// tmp2: Singe level
+
 void Element::Element_PAPR()
 {
 	Identifier = "DEFAULT_PT_PAPR";
@@ -14,7 +23,7 @@ void Element::Element_PAPR()
 
 	Advection = 0.0f;
 	AirDrag = 0.00f * CFDS;
-	AirLoss = 0.90f;
+	AirLoss = 0.995f;
 	Loss = 0.00f;
 	Collision = 0.0f;
 	Gravity = 0.0f;
@@ -22,14 +31,14 @@ void Element::Element_PAPR()
 	HotAir = 0.000f	* CFDS;
 	Falldown = 0;
 
-	Flammable = 20;
+	Flammable = 0;
 	Explosive = 0;
 	Meltable = 0;
 	Hardness = 15;
 
 	Weight = 100;
 
-	HeatConduct = 164;
+	HeatConduct = 80;
 	Description = "Paper. Flammable, readable, writable.";
 
 	Properties = TYPE_SOLID | PROP_NEUTPENETRATE;
@@ -40,8 +49,8 @@ void Element::Element_PAPR()
 	HighPressureTransition = NT;
 	LowTemperature = ITL;
 	LowTemperatureTransition = NT;
-	HighTemperature = 873.0f;
-	HighTemperatureTransition = PT_FIRE;
+	HighTemperature = 700.0f;
+	HighTemperatureTransition = PT_NONE; // Add ash or broken paper element?
 
 	Update = &update;
 	Graphics = &graphics;
@@ -49,33 +58,36 @@ void Element::Element_PAPR()
 
 static int update(UPDATE_FUNC_ARGS)
 {
-	if (parts[i].temp > 450 && parts[i].temp > parts[i].tmp)
-		parts[i].tmp = (int)parts[i].temp;
-
-	if (parts[i].temp > 773.0f && sim->pv[y/CELL][x/CELL] <= -10.0f)
+	if (parts[i].temp > 450 && parts[i].temp >= parts[i].tmp2)
 	{
-		float temp = parts[i].temp;
-		sim->create_part(i, x, y, PT_BCOL);
-		parts[i].temp = temp;
+		parts[i].tmp2 = (int)parts[i].temp;
 	}
 
+	// Auto-ignition temperature
+	if (parts[i].temp > (451.0f - 32.f) / 1.8f + 273.15f)
+	{
+		parts[i].temp += 1;
+		if (sim->rng.chance((int)parts[i].temp-450,400))
+		{
+			int np = sim->create_part(-1, x + sim->rng.between(-1, 1), y + sim->rng.between(-1, 1), PT_FIRE);
+			if (np >= 0)
+			{
+				parts[np].life = 70;
+				// parts[np].temp = parts[i].temp;
+			}
+		}
+	}
 	return 0;
 }
 
 static int graphics(GRAPHICS_FUNC_ARGS)
 {
-	float maxtemp = std::max((float)cpart->tmp, cpart->temp);
-	if (maxtemp > 400)
+	float maxtemp = std::max((float)cpart->tmp2, cpart->temp);
+	if (maxtemp > 450)
 	{
-		*colr -= (int)restrict_flt((maxtemp-400)/3,0,172);
-		*colg -= (int)restrict_flt((maxtemp-400)/4,0,140);
-		*colb -= (int)restrict_flt((maxtemp-400)/20,0,44);
-	}
-	if (maxtemp < 273)
-	{
-		*colr -= (int)restrict_flt((273-maxtemp)/5,0,40);
-		*colg += (int)restrict_flt((273-maxtemp)/4,0,40);
-		*colb += (int)restrict_flt((273-maxtemp)/1.5,0,150);
+		*colr -= (int)restrict_flt((maxtemp-450)*1.2f,0,230);
+		*colg -= (int)restrict_flt((maxtemp-450)*1.4f,0,230);
+		*colb -= (int)restrict_flt((maxtemp-450)*1.7f,0,197);
 	}
 	return 0;
 }