From 484bafa8289ffc705679e2f55ea36c92e24bbc92 Mon Sep 17 00:00:00 2001
From: hugova <hugova@kth.se>
Date: Sat, 28 Jun 2025 21:10:59 +0200
Subject: [PATCH] Fix quartercircle offset isse (before the circle had the
 offset (0,0) always!)

---
 wip-hugo/routines/circle/circle.inc |  6 ++++--
 wip-hugo/routines/circle/circle.s   | 18 +++++++++---------
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/wip-hugo/routines/circle/circle.inc b/wip-hugo/routines/circle/circle.inc
index 598af41..855eead 100644
--- a/wip-hugo/routines/circle/circle.inc
+++ b/wip-hugo/routines/circle/circle.inc
@@ -3,5 +3,7 @@
 ;; public args
         radius = ARGVEC + 2
 ;; private args
-        t1   = $E0
-        t2   = $E1
+        t1    = $E0
+        t2    = $E1
+        X_rel = radius
+        Y_rel = $E3
diff --git a/wip-hugo/routines/circle/circle.s b/wip-hugo/routines/circle/circle.s
index b11f683..2da3b60 100644
--- a/wip-hugo/routines/circle/circle.s
+++ b/wip-hugo/routines/circle/circle.s
@@ -5,13 +5,11 @@
         ;; We use the algorithm jerkos method
         ;; https://schwarzers.com/algorithms/
 
+        ;; X_rel = radius (share the same address)
 
-        ;; X_pos is changed (fix this later)
-        LDA radius
-        STA X_pos
-
+        ;;Y_rel =0
         LDA #$00
-        STA Y_pos
+        STA Y_rel
 
         ;; t1 = radius >> 4
         LDA radius
@@ -25,28 +23,30 @@ while_x_bigger_then_y:
         JSR pixel_draw
 
         INC Y_pos ; y++
+        INC Y_rel
 
         ;;t1 += y
         CLC
         LDA t1
-        ADC Y_pos
+        ADC Y_rel
         STA t1
         ;; t2 = t1 - x
         SEC
         LDA t1
-        SBC X_pos
+        SBC X_rel
         STA t2
         ;; if t2 < 0 then skip to endif
         CMP #$00
         BMI endif
 if:
         DEC X_pos ; x--
+        DEC X_rel
         LDA t2
         STA t1    ; t1 = t2
 endif:
         ;; repeat if X > Y
-        LDA X_pos
-        CMP Y_pos
+        LDA X_rel
+        CMP Y_rel
 
         BCS while_x_bigger_then_y
         RTS