From 56c2eb1b947c682a78c5909fee6cf4285683dc51 Mon Sep 17 00:00:00 2001
From: Jeremy Penner <jeremy@sporktania.com>
Date: Sat, 14 Nov 2020 22:54:43 -0500
Subject: [PATCH] fix redrawing map tile

---
 game/init.fnl | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/game/init.fnl b/game/init.fnl
index 05dbd49..287076d 100644
--- a/game/init.fnl
+++ b/game/init.fnl
@@ -148,8 +148,29 @@
   [:tya] [:and 0xe0]
   [:sta vm.TOP :x])
 
-(vm:word :drawtile-at ; xy --
-  :drop) ; todo
+(vm:def :itile-at ; yx -- itile
+  [:lda (- maph 1)]
+  [:sec]
+  [:sbc vm.TOPH :x]
+  [:asl :a] ; x2
+  [:asl :a] ; x4
+  [:sta vm.TOPH :x]
+  [:asl :a] ; x8
+  [:asl :a] ; x16
+  [:clc] [:adc vm.TOPH :x] ; x20
+  [:adc vm.TOP :x]
+  [:sta vm.TOP :x]
+  [:lda #(hi ($1:lookup-addr :map))]
+  [:sta vm.TOPH :x]
+  [:lda [vm.TOP :x]]
+  [:sta vm.TOP :x]
+  [:lda 0]
+  [:sta vm.TOPH :x])
+
+(vm:word :drawtile-at ; yx --
+  :dup :yx>screen :swap
+  :itile-at :lookup-tile
+  :drawtile)
 
 (vm:def :last-key ; -- key
   (vm:reserve)