From cf80e313b17aecad8e1d0fe332c79185e0364054 Mon Sep 17 00:00:00 2001
From: xokz <106196742+xokz@users.noreply.github.com>
Date: Thu, 28 Sep 2023 14:46:32 -0400
Subject: [PATCH 1/4] Update bitmap4.rs

colors of lower values can now overwrite colors of higher values.
---
 agb/src/display/bitmap4.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/agb/src/display/bitmap4.rs b/agb/src/display/bitmap4.rs
index b40eff9c..91fe3a48 100644
--- a/agb/src/display/bitmap4.rs
+++ b/agb/src/display/bitmap4.rs
@@ -48,9 +48,9 @@ impl Bitmap4 {
 
         let c = addr.get(x_in_screen, y_in_screen);
         if x & 0b1 != 0 {
-            addr.set(x_in_screen, y_in_screen, c | u16::from(colour) << 8);
+            addr.set(x_in_screen, y_in_screen, (c & 0xff) | u16::from(colour) << 8);
         } else {
-            addr.set(x_in_screen, y_in_screen, c | u16::from(colour));
+            addr.set(x_in_screen, y_in_screen, (c & 0xff00) | u16::from(colour));
         }
     }
 

From 575976bf527a50dc2389e461b279d0a8e3ed3f90 Mon Sep 17 00:00:00 2001
From: xokz <106196742+xokz@users.noreply.github.com>
Date: Thu, 28 Sep 2023 15:03:24 -0400
Subject: [PATCH 2/4] Update bitmap4.rs

---
 agb/src/display/bitmap4.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/agb/src/display/bitmap4.rs b/agb/src/display/bitmap4.rs
index 91fe3a48..4ef454e2 100644
--- a/agb/src/display/bitmap4.rs
+++ b/agb/src/display/bitmap4.rs
@@ -48,9 +48,9 @@ impl Bitmap4 {
 
         let c = addr.get(x_in_screen, y_in_screen);
         if x & 0b1 != 0 {
-            addr.set(x_in_screen, y_in_screen, (c & 0xff) | u16::from(colour) << 8);
+            addr.set(x_in_screen, y_in_screen, c & 0xff | u16::from(colour) << 8);
         } else {
-            addr.set(x_in_screen, y_in_screen, (c & 0xff00) | u16::from(colour));
+            addr.set(x_in_screen, y_in_screen, c & 0xff00 | u16::from(colour));
         }
     }
 

From 74ccdfcd7fc77c975f7197cd10fd01e6c6224605 Mon Sep 17 00:00:00 2001
From: Corwin <corwin@kuiper.dev>
Date: Thu, 28 Sep 2023 21:19:07 +0100
Subject: [PATCH 3/4] update example to excersise the broken case

---
 agb/examples/bitmap4.rs | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/agb/examples/bitmap4.rs b/agb/examples/bitmap4.rs
index a46f6c72..3084cfa4 100644
--- a/agb/examples/bitmap4.rs
+++ b/agb/examples/bitmap4.rs
@@ -1,7 +1,7 @@
 #![no_std]
 #![no_main]
 
-use agb::display;
+use agb::display::{self, HEIGHT, WIDTH};
 
 #[agb::entry]
 fn main(mut gba: agb::Gba) -> ! {
@@ -11,25 +11,22 @@ fn main(mut gba: agb::Gba) -> ! {
     bitmap.set_palette_entry(1, 0x001F);
     bitmap.set_palette_entry(2, 0x03E0);
 
-    bitmap.draw_point_page(
-        display::WIDTH / 2,
-        display::HEIGHT / 2,
-        1,
-        display::bitmap4::Page::Front,
-    );
-    bitmap.draw_point_page(
-        display::WIDTH / 2 + 5,
-        display::HEIGHT / 2,
-        2,
-        display::bitmap4::Page::Back,
-    );
+    for y in 0..HEIGHT {
+        for x in 0..WIDTH {
+            bitmap.draw_point_page(x, y, 0xF, display::bitmap4::Page::Front);
+            bitmap.draw_point_page(x, y, 1, display::bitmap4::Page::Front);
+            bitmap.draw_point_page(x, y, 0xFF, display::bitmap4::Page::Back);
+            bitmap.draw_point_page(x, y, 2, display::bitmap4::Page::Back);
+        }
+    }
 
-    let mut count = 0;
+    let mut input = agb::input::ButtonController::new();
 
     loop {
         vblank.wait_for_vblank();
-        count += 1;
-        if count % 6 == 0 {
+        input.update();
+
+        if input.is_just_pressed(agb::input::Button::A) {
             bitmap.flip_page();
         }
     }

From e2bff6dffff73d4558964c98df432bfae94c05ad Mon Sep 17 00:00:00 2001
From: Corwin <corwin@kuiper.dev>
Date: Thu, 28 Sep 2023 21:20:56 +0100
Subject: [PATCH 4/4] update changelog

---
 CHANGELOG.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 11497da3..568443f0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 - Text renderer can now be re-used which is useful for rpg style character/word at a time text boxes.
 
+### Fixed
+- Fixed a bug in bitmap4 that caused setting pixels to be always incorrect.
+
 ## [0.12.2] - 2022/10/22
 
 This is a minor release to fix an alignment issue with background tiles.