From 4da737135d8e9c3bca629def39704325140597ec Mon Sep 17 00:00:00 2001
From: Samuel Walker <swalker@piwalker.net>
Date: Fri, 21 Feb 2025 12:36:25 -0700
Subject: [PATCH] fixed zelda line weirdness

---
 include/ppu.h      | 1 +
 lib/ppu_pipeline.c | 8 ++++----
 lib/ppu_sm.c       | 1 +
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/ppu.h b/include/ppu.h
index 6a9c39f..dcc1941 100644
--- a/include/ppu.h
+++ b/include/ppu.h
@@ -40,6 +40,7 @@ typedef struct {
     u8 map_x;
     u8 tile_y;
     u8 fifo_x;
+    u8 lo_scroll_x; 
 } pixel_fifo_context;
 
 typedef struct {
diff --git a/lib/ppu_pipeline.c b/lib/ppu_pipeline.c
index 8a214d8..c4d331a 100644
--- a/lib/ppu_pipeline.c
+++ b/lib/ppu_pipeline.c
@@ -41,7 +41,7 @@ u32 pixel_fifo_pop() {
 u32 fetch_sprite_pixels(int bit, u32 color, u8 bg_color) {
     for (int i = 0; i < ppu_get_context()->fetched_entry_count; i++) {
         int sp_x = (ppu_get_context()->fetched_entries[i].x - 8) +
-            ((lcd_get_context()->scroll_x % 8));
+            ((ppu_get_context()->pfc.lo_scroll_x));
         if(ppu_get_context()->rendering_window) { 
             sp_x = (ppu_get_context()->fetched_entries[i].x - 8);
         }
@@ -92,7 +92,7 @@ bool pipeline_fifo_add() {
         return false;
     }
 
-    int x = ppu_get_context()->pfc.fetch_x - (8 - lcd_get_context()->scroll_x % 8);
+    int x = ppu_get_context()->pfc.fetch_x - (8 - ppu_get_context()->pfc.lo_scroll_x);
 
     for (int i=0; i<8; i++) {
         int bit = 7 - i;
@@ -121,7 +121,7 @@ void pipeline_load_sprite_tile() {
     oam_line_entry *le = ppu_get_context()->line_sprites;
 
     while(le) {
-        int sp_x = (le->entry.x - 8) + (lcd_get_context()->scroll_x % 8);
+        int sp_x = (le->entry.x - 8) + (ppu_get_context()->pfc.lo_scroll_x);
 
         if ((sp_x >= ppu_get_context()->pfc.fetch_x && sp_x < ppu_get_context()->pfc.fetch_x + 8) ||
             ((sp_x + 8) >= ppu_get_context()->pfc.fetch_x && (sp_x + 8) < ppu_get_context()->pfc.fetch_x + 8)) {
@@ -292,7 +292,7 @@ void pipeline_push_pixel() {
 
                 ppu_get_context()->pfc.pushed_x++;
         }else {
-            if(ppu_get_context()->pfc.line_x >= (lcd_get_context()->scroll_x % 8)) {
+            if(ppu_get_context()->pfc.line_x >= (ppu_get_context()->pfc.lo_scroll_x)) {
                 ppu_get_context()->video_buffer[ppu_get_context()->pfc.pushed_x +
                     (lcd_get_context()->ly * XRES)] = interpolate(ppu_get_context()->video_buffer[ppu_get_context()->pfc.pushed_x +
                         (lcd_get_context()->ly * XRES)], pixel_data);
diff --git a/lib/ppu_sm.c b/lib/ppu_sm.c
index 239198e..1986be1 100644
--- a/lib/ppu_sm.c
+++ b/lib/ppu_sm.c
@@ -94,6 +94,7 @@ void ppu_mode_oam() {
     }
 
     if(ppu_get_context()->line_ticks == 1) {
+        ppu_get_context()->pfc.lo_scroll_x = lcd_get_context()->scroll_x & 0b111;
         //read oam on the first tick only...
         ppu_get_context()->line_sprites = 0;
         ppu_get_context()->line_sprite_count = 0;