From 5220729b8078c0b12dfbd403fb443c969362547b Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Wed, 19 Dec 2018 21:12:39 +0100
Subject: Extract equilibrium function

---
 src/shader/code/collide.glsl | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/shader/code/collide.glsl b/src/shader/code/collide.glsl
index 7b5534a..3510c4e 100644
--- a/src/shader/code/collide.glsl
+++ b/src/shader/code/collide.glsl
@@ -94,6 +94,12 @@ vec2 velocity(uint x, uint y, float d) {
 	);
 }
 
+/// Equilibrium distribution
+
+float equilibrium(float d, vec2 v, int i, int j) {
+	return w(i,j) * d * (1 + 3*comp(i,j,v) + 4.5*sq(comp(i,j,v)) - 1.5*sq(norm(v)));
+}
+
 /// Determine external influence
 
 float getExternalPressureInflux(uint x, uint y) {
@@ -121,8 +127,7 @@ void main() {
 
 	for ( int i = -1; i <= 1; ++i ) {
 		for ( int j = -1; j <= 1; ++j ) {
-			const float eq = w(i,j) * d * (1 + 3*comp(i,j,v) + 4.5*sq(comp(i,j,v)) - 1.5*sq(norm(v)));
-			set(x,y,i,j, get(x,y,i,j) + omega * (eq - get(x,y,i,j)));
+			set(x,y,i,j, get(x,y,i,j) + omega * (equilibrium(d,v,i,j) - get(x,y,i,j)));
 		}
 	}
 }
-- 
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