From f784e4c57d2a019263a5875c0bd8789fa8e079fe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Sun, 7 May 2023 00:57:55 +0100
Subject: [PATCH] chore: improved PPU performance for DMG By avoiding many of
the GBC required operations in the drawing pipeline.
---
src/ppu.rs | 46 +++++++++++++++++-----------------------------
1 file changed, 17 insertions(+), 29 deletions(-)
diff --git a/src/ppu.rs b/src/ppu.rs
index 8695ee6c..74a549ed 100644
--- a/src/ppu.rs
+++ b/src/ppu.rs
@@ -1143,6 +1143,9 @@ impl Ppu {
// bank in which the tile is stored, this is only required for CGB mode
tile_index += tile_attr.vram_bank as usize * TILE_COUNT_DMG;
+ // obtains the reference to the tile that is going to be drawn
+ let mut tile = &self.tiles[tile_index];
+
// calculates the offset that is going to be used in the update of the color buffer
// which stores Game Boy colors from 0 to 3
let mut color_offset = self.ly as usize * DISPLAY_WIDTH;
@@ -1163,8 +1166,8 @@ impl Ppu {
if index as i16 >= wx as i16 - 7 {
// obtains the current pixel data from the tile and
// re-maps it according to the current palette
- let pixel = self.tiles[tile_index].get_flipped(x, y, xflip, yflip);
- let color = palette[pixel as usize];
+ let pixel = tile.get_flipped(x, y, xflip, yflip);
+ let color = &palette[pixel as usize];
// updates the pixel in the color buffer, which stores
// the raw pixel color information (unmapped)
@@ -1196,34 +1199,19 @@ impl Ppu {
tile_index += 256;
}
- // obtains the reference to the attributes of the new tile in
- // drawing for meta processing (CGB only)
- tile_attr = if self.dmg_compat {
- &DEFAULT_TILE_ATTR
- } else {
- &bg_map_attrs[row_offset + line_offset]
- };
-
- // retrieves the proper palette for the current tile in drawing
- // taking into consideration if we're running in CGB mode or not
- palette = if self.gb_mode == GameBoyMode::Cgb {
- if self.dmg_compat {
- &self.palette_bg
- } else {
- &self.palettes_color_bg[tile_attr.palette as usize]
- }
- } else {
- &self.palette_bg
- };
-
- // obtains the values of both X and Y flips for the current tile
- // they will be applied by the get tile pixel method
- xflip = tile_attr.xflip;
- yflip = tile_attr.yflip;
+ // in case the current mode is CGB and the DMG compatibility
+ // flag is not set then a series of tile values must be
+ // updated according to the tile attributes field
+ if self.gb_mode == GameBoyMode::Cgb && !self.dmg_compat {
+ tile_attr = &bg_map_attrs[row_offset + line_offset];
+ palette = &self.palettes_color_bg[tile_attr.palette as usize];
+ xflip = tile_attr.xflip;
+ yflip = tile_attr.yflip;
+ tile_index += tile_attr.vram_bank as usize * TILE_COUNT_DMG;
+ }
- // increments the tile index value by the required offset for the VRAM
- // bank in which the tile is stored, this is only required for CGB mode
- tile_index += tile_attr.vram_bank as usize * TILE_COUNT_DMG;
+ // obtains the reference to the new tile in drawing
+ tile = &self.tiles[tile_index];
}
}
--
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