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-rw-r--r--src/ppu.rs20
1 files changed, 12 insertions, 8 deletions
diff --git a/src/ppu.rs b/src/ppu.rs
index c5b4aec..54dbc0b 100644
--- a/src/ppu.rs
+++ b/src/ppu.rs
@@ -488,9 +488,10 @@ impl<'a> PPU<'a> {
self.cycle = cycle + 1;
return false;
}
+ let rendering = self.get_show_bg() || self.get_show_sp();
let visible_line = self.scanline < 240;
let pre_line = self.scanline == 261;
- if (pre_line || visible_line) && (self.get_show_bg() || self.get_show_sp()) {
+ if (pre_line || visible_line) && rendering {
if pre_line && 279 < cycle && cycle < 305 {
self.reset_y();
} else {
@@ -534,14 +535,17 @@ impl<'a> PPU<'a> {
self.bg_pixel = 0;
}
}
- } else if self.scanline == 241 && cycle == 1 {
- if !self.early_read {
- self.ppustatus |= PPU::FLAG_VBLANK;
+ } else {
+ if !rendering { self.bg_pixel = 0 }
+ if self.scanline == 241 && cycle == 1 {
+ if !self.early_read {
+ self.ppustatus |= PPU::FLAG_VBLANK;
+ }
+ self.scr.render();
+ self.cycle += 1;
+ self.early_read = false;
+ return !self.early_read && self.get_flag_nmi(); /* trigger cpu's NMI */
}
- self.scr.render();
- self.cycle += 1;
- self.early_read = false;
- return !self.early_read && self.get_flag_nmi(); /* trigger cpu's NMI */
}
self.cycle += 1;
if self.cycle > 340 {