From 45efb366f3b4cff0b48d19a3e0658c46faef5403 Mon Sep 17 00:00:00 2001
From: Fabien Freling <public@ffreling.com>
Date: Thu, 28 Mar 2019 13:16:31 +0100
Subject: [PATCH] Fix fire effect in wren

---
 doom_fire.wren | 33 +++++++++++++++++++++------------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/doom_fire.wren b/doom_fire.wren
index 3377378..f0cdd5e 100644
--- a/doom_fire.wren
+++ b/doom_fire.wren
@@ -9,9 +9,11 @@ class Game is TIC{
 
 	construct new(){
 		_t=0
+		_width = 240
+		_height = 136
 		// Init to black
-		_base = List.filled(240 * 136, 0)
-		for (last_line in (240 * 135)...(240 * 136)) {
+		_base = List.filled(_width * _height, 0)
+		for (last_line in (_width * (_height-1))...(_width * _height)) {
 		  _base[last_line] = 15
 		}
 	 _random = Random.new(12345) 
@@ -19,26 +21,33 @@ class Game is TIC{
 	}
 	
 	dofire() {
-		for (x in 0...240) {
-			for (y in 135..1) {
+		for (x in 0..._width) {
+			for (y in 0...(_height-1)) {
 				spreadfire(x, y)
 			}
 		}
 	}
 	
 	spreadfire(x, y) {
-		var rand = _random.int(2)
-		var delta = rand
-		var index = x + y * 240
-		_base[index - 240] = _base[index] - delta
-		if (_base[index - 240] < 0) {
-			_base[index - 240] = 0
+		var rand = _random.int(4) // [0, 3]
+		var delta = rand & 1
+		var side = -rand+1 // [-2, 1]
+		if (x+side < 0) {
+			side=0
+		}
+		if (x+side >= _width) {
+			side = 0
+		}
+		var index = x + (y*240)
+		_base[index+side] = _base[index + _width] - delta
+		if (_base[index+side] < 0) {
+			_base[index+side] = 0
 		}
 	}
 	
 	TIC(){
-		for (y in 0...136) {
-			for (x in 0...240) {
+		for (y in 0..._height) {
+			for (x in 0..._width) {
 				TIC.pix(x, y, _base[x + y * 240])
 			}
 		}