From 1cf33af24a8336636d96acdf9f1e80cc8246371c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Sun, 30 Apr 2023 00:30:01 +0100
Subject: [PATCH] chore: initial support for color palette processing The code
is still pending extensive test and some errors may exist.
---
src/gb.rs | 4 ++--
src/ppu.rs | 57 ++++++++++++++++++++++++++++++++++++++++--------------
2 files changed, 44 insertions(+), 17 deletions(-)
diff --git a/src/gb.rs b/src/gb.rs
index ae412854..ac960219 100644
--- a/src/gb.rs
+++ b/src/gb.rs
@@ -499,10 +499,10 @@ impl GameBoy {
/// Obtains the pixel buffer for the tile at the
/// provided index, converting the color buffer
- /// using the currently loaded palette.
+ /// using the currently loaded (background) palette.
pub fn get_tile_buffer(&mut self, index: usize) -> Vec<u8> {
let tile = self.get_tile(index);
- tile.palette_buffer(self.ppu().palette())
+ tile.palette_buffer(self.ppu().palette_bg())
}
/// Obtains the name of the compiler that has been
diff --git a/src/ppu.rs b/src/ppu.rs
index 40391df5..d0b349c3 100644
--- a/src/ppu.rs
+++ b/src/ppu.rs
@@ -291,8 +291,8 @@ pub struct Ppu {
palette_colors: Palette,
/// The palette of colors that is currently loaded in Game Boy
- /// and used for background (tiles).
- palette: Palette,
+ /// and used for background (tiles) and window.
+ palette_bg: Palette,
/// The palette that is going to be used for sprites/objects #0.
palette_obj_0: Palette,
@@ -312,8 +312,9 @@ pub struct Ppu {
/// be re-read if required by the system.
palettes: [u8; 3],
- /// The raw byte information (64 bytes) for the color palettes,
- /// both the background and the objects one (CGB only).
+ /// The raw binary information (64 bytes) for the color palettes,
+ /// contains binary information for both the background and
+ /// the objects palettes (CGB only).
palettes_color: [[u8; 64]; 2],
/// The complete list of attributes for the first background
@@ -452,7 +453,7 @@ impl Ppu {
tiles: [Tile { buffer: [0u8; 64] }; TILE_COUNT],
obj_data: [ObjectData::default(); OBJ_COUNT],
palette_colors: PALETTE_COLORS,
- palette: [[0u8; RGB_SIZE]; PALETTE_SIZE],
+ palette_bg: [[0u8; RGB_SIZE]; PALETTE_SIZE],
palette_obj_0: [[0u8; RGB_SIZE]; PALETTE_SIZE],
palette_obj_1: [[0u8; RGB_SIZE]; PALETTE_SIZE],
palettes_color_bg: [[[0u8; RGB_SIZE]; PALETTE_SIZE]; 8],
@@ -501,7 +502,7 @@ impl Ppu {
self.vram_bank = 0x0;
self.vram_offset = 0x0000;
self.tiles = [Tile { buffer: [0u8; 64] }; TILE_COUNT];
- self.palette = [[0u8; RGB_SIZE]; PALETTE_SIZE];
+ self.palette_bg = [[0u8; RGB_SIZE]; PALETTE_SIZE];
self.palette_obj_0 = [[0u8; RGB_SIZE]; PALETTE_SIZE];
self.palette_obj_1 = [[0u8; RGB_SIZE]; PALETTE_SIZE];
self.palettes_color_bg = [[[0u8; RGB_SIZE]; PALETTE_SIZE]; 8];
@@ -719,7 +720,7 @@ impl Ppu {
0xff43 => self.scx = value,
0xff45 => self.lyc = value,
0xff47 => {
- Self::compute_palette(&mut self.palette, &self.palette_colors, value);
+ Self::compute_palette(&mut self.palette_bg, &self.palette_colors, value);
self.palettes[0] = value;
}
0xff48 => {
@@ -744,10 +745,16 @@ impl Ppu {
}
// 0xFF69 — BCPD/BGPD (CGB only)
0xff69 => {
- self.palettes_color[0][self.palette_address_bg as usize] = value;
- //@TODO: update palette background data accordingly for the given update
- // index - should not be a problem
- // compute_palette_color should probably be the name
+ let mut palette_color = self.palettes_color[0];
+ palette_color[self.palette_address_bg as usize] = value;
+
+ let palette_index = self.palette_address_bg / 8;
+ Self::compute_palette_color(
+ &mut self.palettes_color_bg[palette_index as usize],
+ &palette_color,
+ palette_index,
+ );
+
if self.auto_increment_bg {
self.palette_address_bg = (self.palette_address_bg + 1) & 0x3f;
}
@@ -789,8 +796,8 @@ impl Ppu {
self.compute_palettes()
}
- pub fn palette(&self) -> Palette {
- self.palette
+ pub fn palette_bg(&self) -> Palette {
+ self.palette_bg
}
pub fn palette_obj_0(&self) -> Palette {
@@ -1013,7 +1020,7 @@ impl Ppu {
// obtains the current pixel data from the tile and
// re-maps it according to the current palette
let pixel = self.tiles[tile_index].get(x, y);
- let color = self.palette[pixel as usize];
+ let color = self.palette_bg[pixel as usize];
// updates the pixel in the color buffer, which stores
// the raw pixel color information (unmapped)
@@ -1219,7 +1226,7 @@ impl Ppu {
fn compute_palettes(&mut self) {
// re-computes the complete set of palettes according to
// the currently set palette colors (that may have changed)
- Self::compute_palette(&mut self.palette, &self.palette_colors, self.palettes[0]);
+ Self::compute_palette(&mut self.palette_bg, &self.palette_colors, self.palettes[0]);
Self::compute_palette(
&mut self.palette_obj_0,
&self.palette_colors,
@@ -1249,6 +1256,26 @@ impl Ppu {
}
}
}
+
+ /// Static method that computes an RGB888 color palette ready to
+ /// be used for frame buffer operations from 4 (colors) x 2 bytes (RGB555)
+ /// that represent an RGB555 set of colors. This method should be
+ /// used for CGB mode where colors are represented using RGB555.
+ fn compute_palette_color(palette: &mut Palette, palette_color: &[u8; 64], palette_index: u8) {
+ let palette_offset = palette_index * 4 * 2;
+ for (index, palette_item) in palette.iter_mut().enumerate() {
+ let color_index: usize = palette_offset as usize + index * 2;
+ *palette_item =
+ Self::rgb555_to_rgb888(palette_color[color_index], palette_color[color_index + 1]);
+ }
+ }
+
+ fn rgb555_to_rgb888(first: u8, second: u8) -> Pixel {
+ let r = first & 0x1f << 3;
+ let g = (first & 0xe0 >> 5 | (second & 0x03) << 3) << 3;
+ let b = ((second & 0x7c) >> 2) << 3;
+ [r as u8, g as u8, b as u8]
+ }
}
impl Default for Ppu {
--
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