From 9d401a58619a9bf45ea218db5faebb349db4e7f8 Mon Sep 17 00:00:00 2001
From: Lucas Scharenbroich <lscharen@prowestgis.com>
Date: Mon, 21 Feb 2022 14:25:55 -0600
Subject: [PATCH] Fix masking bug in sprite pre-calc

---
 src/Sprite.s       |  2 +-
 src/Sprite2.s      | 19 +++++++++++++------
 src/SpriteRender.s |  2 +-
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/Sprite.s b/src/Sprite.s
index c8c935e..cf6253c 100644
--- a/src/Sprite.s
+++ b/src/Sprite.s
@@ -586,7 +586,7 @@ SPRITE_PLANE_SPAN equ VBUFF_STRIDE_BYTES        ; 52
 ; X = sprite index
 _PrecalcAllSpriteInfo
             lda   _Sprites+SPRITE_ID,x 
-            and   #$2E00
+            and   #$3E00
             xba
             sta   _Sprites+SPRITE_DISP,x        ; use bits 9 through 13 for full dispatch
 
diff --git a/src/Sprite2.s b/src/Sprite2.s
index 9bc35d2..d3feb2d 100644
--- a/src/Sprite2.s
+++ b/src/Sprite2.s
@@ -114,9 +114,12 @@ _MarkDirtySprite
 
         txa
         and   #$0007
-        clc
-        adc   _Sprites+SPRITE_CLIP_HEIGHT,y
+        pha
+
+        lda   _Sprites+SPRITE_CLIP_HEIGHT,y       ; Nominal value between 0 and 16+7 = 23 = 10111
         dec
+        clc
+        adc   1,s
         and   #$0018
         sta   AreaIndex
 
@@ -135,13 +138,17 @@ _MarkDirtySprite
 
         txa
         and   #$0003
-        clc
-        adc   _Sprites+SPRITE_CLIP_WIDTH,y
+        sta   1,s
+
+        lda   _Sprites+SPRITE_CLIP_WIDTH,y       ; max width = 8 = 0x08
         dec
-        and   #$000C
-        lsr
+        clc
+        adc   1,s
+        lsr                                      ; max value = 4 = 0x04
+        and   #$0006
         ora   AreaIndex
         sta   AreaIndex
+        pla
 
 ; Calculate the modified origin address for the sprite.  We need to look at the sprite flip bits
 ; to determine which of the four sprite stamps is the correct one to use.  Then, offset that origin
diff --git a/src/SpriteRender.s b/src/SpriteRender.s
index 2e5386b..5a4b1ca 100644
--- a/src/SpriteRender.s
+++ b/src/SpriteRender.s
@@ -4,7 +4,7 @@
 _DrawSpriteSheet
 DISP_VFLIP   equ    $0004      ; hard code these because they are internal values
 DISP_HFLIP   equ    $0002
-DISP_MASK    equ    $00F9
+DISP_MASK    equ    $0018      ; Isolate the size bits
 
              phx