From 268193f4891708c6bd53ba8f6246f1654ad41961 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Fri, 1 Jul 2022 11:22:03 +0100
Subject: [PATCH] feat: better drawing of line
---
src/mmu.rs | 1 -
src/ppu.rs | 12 +++++++-----
2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/src/mmu.rs b/src/mmu.rs
index 56a7999b..8c79e05e 100644
--- a/src/mmu.rs
+++ b/src/mmu.rs
@@ -111,7 +111,6 @@ impl Mmu {
}
// Graphics: VRAM (8k)
0x8000 | 0x9000 => {
- println!("WRITING TO VRAM");
self.ppu.vram[(addr & 0x1fff) as usize] = value;
if addr < 0x9800 {
self.ppu.update_tile(addr, value);
diff --git a/src/ppu.rs b/src/ppu.rs
index 9c0e8ee0..4283078c 100644
--- a/src/ppu.rs
+++ b/src/ppu.rs
@@ -214,16 +214,18 @@ impl Ppu {
let y = ((self.scy + self.line) & 0x07) as usize;
let mut x = (self.scx & 0x07) as usize;
- let mut frame_offset = self.line as usize * SCREEN_WIDTH * RGBA_SIZE;
-
+ // calculates the index of the initial tile in drawing,
+ // if the tile data set in use is #1, the indices are
+ // signed, then calculates a real tile offset
let mut tile_index = self.vram[map_offset + line_offset] as usize;
-
- // if the tile data set in use is #1, the
- // indices are signed, calculates a real tile offset
if self.bg_tile && tile_index < 128 {
tile_index += 256;
}
+ // calculates the frame buffer offset position assuming the proper
+ // Game Boy screen width and RGBA pixel (4 bytes) size
+ let mut frame_offset = self.line as usize * SCREEN_WIDTH * RGBA_SIZE;
+
for _index in 0..SCREEN_WIDTH {
// in case the end of tile width has been reached then
// a new tile must be retrieved for plotting
--
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