From: Esko Kokkonen <esko.kokkonen@gmail.com>
Date: Sat, 1 May 2010 14:23:23 +0000 (+0300)
Subject: merge_planets: Calculate new color for the remaining planet
X-Git-Url: http://git.itanic.dy.fi/?p=sdl-planets;a=commitdiff_plain;h=2295e56851607fe4e23c5b5101adc20e68e29b0c

merge_planets: Calculate new color for the remaining planet
---

diff --git a/planet.c b/planet.c
index 2482dd9..a79c085 100644
--- a/planet.c
+++ b/planet.c
@@ -235,15 +235,21 @@ int gravitize_planets(struct planet *a, struct planet *b, const double time)
 static void _merge_planets(struct planet *a, struct planet *b)
 {
 	struct vector pa, pb, p;
+	float mass;
 
 	vector_scale(&a->speed, a->mass, &pa);
 	vector_scale(&b->speed, b->mass, &pb);
 	vector_add(&pa, &pb, &p);
+	mass = a->mass + b->mass;
 
 	if (a->mass < b->mass)
 		a->pos = b->pos;
 
-	a->mass += b->mass;
+	a->r = (a->r * a->mass + b->r * b->mass) / mass;
+	a->g = (a->g * a->mass + b->g * b->mass) / mass;
+	a->b = (a->b * a->mass + b->b * b->mass) / mass;
+
+	a->mass = mass;
 	reshape_planet(a);
 	vector_div(&p, a->mass, &a->speed);
 }