From 233fae545aff4f17389a1c62c7c93dff2b0910a9 Mon Sep 17 00:00:00 2001
From: Matthew Pomes <matthew.pomes@pm.me>
Date: Wed, 8 Apr 2026 22:47:41 -0500
Subject: [PATCH] Fix large sprites

---
 src/ppu.rs | 71 ++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 45 insertions(+), 26 deletions(-)

diff --git a/src/ppu.rs b/src/ppu.rs
index 08ee485..10c1dc7 100644
--- a/src/ppu.rs
+++ b/src/ppu.rs
@@ -164,7 +164,7 @@ impl OAM {
                     OamState::ReadY => {
                         let l = self.oam_read_buffer as usize;
                         if self.count < 8 {
-                            if l <= line && line < l + 8 {
+                            if l <= line && line < l + if self.large_sprites { 16 } else { 8 } {
                                 self.secondary[self.count as usize * 4] = self.oam_read_buffer;
                                 self.state = OamState::ReadTile;
                             } else {
@@ -214,36 +214,55 @@ impl OAM {
                 } else if run % 8 == 3 {
                     self.sprite_output_units[run / 8].x_pos = self.secondary[(run / 8) * 4 + 3];
                 } else if run % 8 == 4 {
-                } else if run % 8 == 5 {
-                    let off = line - self.sprite_output_units[run / 8].y_pos as usize;
-                    let off = if self.sprite_output_units[run / 8].attrs.vflip() {
-                        7 - off
-                    } else {
-                        off
-                    };
-                    let addr = if self.sprite_offset_0x1000 {
-                        0x1000
-                    } else {
-                        0x0000
-                    } + 16 * self.sprite_output_units[run / 8].tile as u16
-                        + off as u16;
-                    self.sprite_output_units[run / 8].low = mem.read(addr).reg_map(|_, _| todo!());
+                    // } else if run % 8 == 5 {
+                    //     let off = line - self.sprite_output_units[run / 8].y_pos as usize;
+                    //     let off = if self.sprite_output_units[run / 8].attrs.vflip() {
+                    //         7 - off
+                    //     } else {
+                    //         off
+                    //     };
+                    //     let addr = if self.sprite_offset_0x1000 {
+                    //         0x1000
+                    //     } else {
+                    //         0x0000
+                    //     } + 16 * self.sprite_output_units[run / 8].tile as u16
+                    //         + off as u16;
+                    //     self.sprite_output_units[run / 8].low = mem.read(addr).reg_map(|_, _| todo!());
                 } else if run % 8 == 6 {
-                } else if run % 8 == 7 {
+                } else if run % 8 == 5 || run % 8 == 7 {
                     let off = line - self.sprite_output_units[run / 8].y_pos as usize;
-                    let off = if self.sprite_output_units[run / 8].attrs.vflip() {
-                        7 - off
+                    let addr = if self.large_sprites {
+                        let off = if self.sprite_output_units[run / 8].attrs.vflip() {
+                            15 - off
+                        } else {
+                            off
+                        };
+                        (if self.sprite_output_units[run / 8].tile & 1 == 1 {
+                            0x1000
+                        } else {
+                            0x0000
+                        } + 16 * (self.sprite_output_units[run / 8].tile & !1) as u16
+                            + off as u16 + if off > 7 { 8 } else { 0 })
                     } else {
-                        off
+                        let off = if self.sprite_output_units[run / 8].attrs.vflip() {
+                            7 - off
+                        } else {
+                            off
+                        };
+                        (if self.sprite_offset_0x1000 {
+                            0x1000
+                        } else {
+                            0x0000
+                        } + 16 * self.sprite_output_units[run / 8].tile as u16
+                            + off as u16)
                     };
-                    let addr = if self.sprite_offset_0x1000 {
-                        0x1000
+                    if run % 8 == 5 {
+                        self.sprite_output_units[run / 8].low =
+                            mem.read(addr).reg_map(|_, _| todo!());
                     } else {
-                        0x0000
-                    } + 16 * self.sprite_output_units[run / 8].tile as u16
-                        + off as u16
-                        + 8;
-                    self.sprite_output_units[run / 8].high = mem.read(addr).reg_map(|_, _| todo!());
+                        self.sprite_output_units[run / 8].high =
+                            mem.read(addr + 8).reg_map(|_, _| todo!());
+                    }
                 }
             }
         }