accuracy PPU: fix incorrect rendering in hires mode (fixes #297)

bsnes/snes/ppu/background/background.cpp

@@ -145,34 +145,36 @@ void PPU::Background::run(bool screen) {
 
  if(regs.mode == Mode::Mode7) return run_mode7();
 
- uint8 palette = get_tile_color();
+ Pixel pixel;
+ pixel.priority = priority;
+ pixel.palette = get_tile_color();
+ if(pixel.palette) pixel.palette += palette_index;
+ pixel.tile = tile;
+
  bool update_mosaic = !hires || screen == Screen::Sub;
  if(x == 0) mosaic_hcounter = 1;
  if((x == 0 && update_mosaic)
  || (x > 0 && update_mosaic && --mosaic_hcounter == 0)) {
  mosaic_hcounter = regs.mosaic ? self.regs.mosaic_size : 1;
- mosaic_priority = priority;
- mosaic_palette = palette ? palette_index + palette : 0;
- mosaic_tile = tile;
+ mosaic = pixel;
+ }
+ else if (regs.mosaic)
+ {
+ pixel = mosaic;
  }
+
  if(screen == Screen::Main) x++;
- if(mosaic_palette == 0) return;
+ if(pixel.palette == 0) return;
 
  if(regs.mode == Mode::Inactive) return;
  if(!hires || screen == Screen::Main) {
- if(regs.main_enable) {
- output.main.priority = mosaic_priority;
- output.main.palette = mosaic_palette;
- output.main.tile = mosaic_tile;
- }
+ if(regs.main_enable)
+ output.main = pixel;
  }
 
  if(!hires || screen == Screen::Sub) {
- if(regs.sub_enable) {
- output.sub.priority = mosaic_priority;
- output.sub.palette = mosaic_palette;
- output.sub.tile = mosaic_tile;
- }
+ if(regs.sub_enable)
+ output.sub = pixel;
  }
 }
 
@@ -222,9 +224,9 @@ void PPU::Background::reset() {
  mosaic_hcounter = 0;
  mosaic_hoffset = 0;
 
- mosaic_priority = 0;
- mosaic_palette = 0;
- mosaic_tile = 0;
+ mosaic.priority = 0;
+ mosaic.palette = 0;
+ mosaic.tile = 0;
 
  tile_counter = 0;
  tile = 0;

bsnes/snes/ppu/background/background.hpp

@@ -25,12 +25,14 @@ class Background {
  unsigned voffset;
  } regs;
 
+ struct Pixel {
+ unsigned priority;
+ uint8 palette; //0 = none (transparent)
+ uint16 tile;
+ };
+
  struct Output {
- struct Pixel {
- unsigned priority; //0 = none (transparent)
- uint8 palette;
- uint16 tile;
- } main, sub;
+ Pixel main, sub;
  } output;
 
  struct {
@@ -39,10 +41,7 @@ class Background {
 
  unsigned mosaic_hcounter;
  unsigned mosaic_hoffset;
-
- unsigned mosaic_priority;
- uint8 mosaic_palette;
- uint16 mosaic_tile;
+ Pixel mosaic;
 
  unsigned tile_counter;
  unsigned tile;

bsnes/snes/ppu/serialization.cpp

@@ -113,9 +113,9 @@ void PPU::Background::serialize(serializer &s) {
  s.integer(mosaic_hcounter);
  s.integer(mosaic_hoffset);
 
- s.integer(mosaic_priority);
- s.integer(mosaic_palette);
- s.integer(mosaic_tile);
+ s.integer(mosaic.priority);
+ s.integer(mosaic.palette);
+ s.integer(mosaic.tile);
 
  s.integer(tile_counter);
  s.integer(tile);