From c8cfcea551bc0f4911e889f21d87c476a946b958 Mon Sep 17 00:00:00 2001
From: Isaac Marovitz <isaacryu@icloud.com>
Date: Wed, 1 May 2024 21:09:00 -0400
Subject: [PATCH] BCPD/OCPD Read Blocking

---
 src/components/ppu/ppu.rs | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/components/ppu/ppu.rs b/src/components/ppu/ppu.rs
index 1fc8310..35bf301 100644
--- a/src/components/ppu/ppu.rs
+++ b/src/components/ppu/ppu.rs
@@ -569,9 +569,21 @@ impl Memory for PPU {
             // TODO: DMA
             0xFF51..=0xFF55 => 0x00,
             0xFF68 => self.bcps.read(),
-            0xFF69 => self.bcpd[self.bcps.address as usize],
+            0xFF69 => {
+                if self.ppu_mode != PPUMode::Draw {
+                    self.bcpd[self.bcps.address as usize]
+                } else {
+                    0xFF
+                }
+            },
             0xFF6A => self.ocps.read(),
-            0xFF6B => self.ocpd[self.ocps.address as usize],
+            0xFF6B => {
+                if self.ppu_mode != PPUMode::Draw {
+                    self.ocpd[self.ocps.address as usize]
+                } else {
+                    0xFF
+                }
+            },
             0xFF6C => self.opri as u8,
             _ => panic!("Read to unsupported PPU address ({:#06x})!", a),
         }