reduce canvas to 1/4 size

apps/litenes/include/ppu.h

@@ -32,5 +32,93 @@ bool ppu_shows_sprites();
 bool ppu_in_vblank();
 void ppu_set_in_vblank(bool yesno);
 
+// PPU Memory and State
+typedef struct {
+    byte PPUCTRL;   // $2000 write only
+    byte PPUMASK;   // $2001 write only
+    byte PPUSTATUS; // $2002 read only
+    byte OAMADDR;   // $2003 write only
+    byte OAMDATA;   // $2004
+	word PPUSCROLL;
+    byte PPUSCROLL_X, PPUSCROLL_Y; // $2005 write only x2
+    word PPUADDR;   // $2006 write only x2
+    word PPUDATA;   // $2007
+
+    bool scroll_received_x;
+    bool addr_received_high_byte;
+    bool ready;
+
+    int mirroring, mirroring_xor;
+
+    int x, scanline;
+} PPU_STATE;
+
+extern PPU_STATE ppu;
+extern byte ppu_latch;
+extern bool ppu_sprite_hit_occured;
+extern byte ppu_screen_background[264][248];
+
+word ppu_get_real_ram_address(word address);
+
+
+// Screen State and Rendering
+
+static inline byte ppu_l_h_addition(int h, int l, int x) {
+  return (((h >> (7 - x)) & 1) << 1) | ((l >> (7 - x)) & 1);
+}
+static inline byte ppu_l_h_addition_flip(int l, int h, int x) {
+  return (((h >> x) & 1) << 1) | ((l >> x) & 1);
+}
+ 
+
+// Draws current screen pixels in ppu_background_pixels & ppu_sprite_pixels and clears them
+void ppu_render_screen();
+void ppu_set_background_color(byte color);
+
+
+
+// PPUCTRL Functions
+
+word ppu_base_nametable_address();
+byte ppu_vram_address_increment();
+word ppu_sprite_pattern_table_address();
+word ppu_background_pattern_table_address();
+byte ppu_sprite_width();
+byte ppu_sprite_height();
+bool ppu_generates_nmi();
+
+
+
+// PPUMASK Functions
+
+bool ppu_renders_grayscale();
+bool ppu_shows_background_in_leftmost_8px();
+bool ppu_shows_sprites_in_leftmost_8px();
+bool ppu_intensifies_reds();
+bool ppu_intensifies_greens();
+bool ppu_intensifies_blues();
+void ppu_set_renders_grayscale(bool yesno);
+void ppu_set_shows_background_in_leftmost_8px(bool yesno);
+void ppu_set_shows_sprites_in_leftmost_8px(bool yesno);
+void ppu_set_shows_background(bool yesno);
+void ppu_set_shows_sprites(bool yesno);
+void ppu_set_intensifies_reds(bool yesno);
+void ppu_set_intensifies_greens(bool yesno);
+void ppu_set_intensifies_blues(bool yesno);
+
+
+
+// PPUSTATUS Functions
+
+bool ppu_sprite_overflow();
+bool ppu_sprite_0_hit();
+bool ppu_in_vblank();
+
+void ppu_set_sprite_overflow(bool yesno);
+void ppu_set_sprite_0_hit(bool yesno);
+void ppu_set_in_vblank(bool yesno);
+
+
+
 
 #endif

apps/litenes/src/fce/cpu-addressing.c

@@ -1,5 +1,4 @@
 #include "cpu.h"
-#include "cpu-internal.h"
 #include "memory.h"
 
 // CPU Addressing Modes

apps/litenes/src/fce/fce.c

@@ -5,7 +5,6 @@
 #include "hal.h"
 #include "nes.h"
 
-_Pixel canvas[W][H];
 
 typedef struct {
     char signature[4];
@@ -115,10 +114,11 @@ void fce_run()
 
 // Rendering
 
+byte canvas[W][H];
+
 void fce_update_screen()
 {
   int idx = ppu_ram_read(0x3F00);
-  _Pixel bgc = palette[idx];
 
   int w = _screen.width;
   int h = _screen.height;
@@ -126,13 +126,14 @@ void fce_update_screen()
   int pad = (w - h) / 2;
   for (int x = pad; x < w - pad; x ++) {
     for (int y = 0; y < h; y ++) {
-      _draw_p(x, y, canvas[(x - pad) * W / h][y * H / h]);
+      _draw_p(x, y, palette[canvas[(x - pad) * W / h][y * H / h]]);
     }
   }
+
   _draw_sync();
 
   for (int i = 0; i < W; i ++)
     for (int j = 0; j < H; j ++)
-      canvas[i][j] = bgc;
+      canvas[i][j] = idx;
 }
 

apps/litenes/src/fce/ppu.c

@@ -1,20 +1,25 @@
 #include "ppu.h"
-#include "ppu-internal.h"
 #include "cpu.h"
 #include "fce.h"
 #include "memory.h"
 #include "hal.h"
 
+static const word ppu_base_nametable_addresses[4] = { 0x2000, 0x2400, 0x2800, 0x2C00 };
+
 byte ppu_sprite_palette[4][4];
 bool ppu_2007_first_read;
 byte ppu_addr_latch;
+PPU_STATE ppu;
+byte ppu_latch;
+bool ppu_sprite_hit_occured = false;
+byte ppu_screen_background[264][248];
 
-
-extern _Pixel canvas[W][H];
+extern byte canvas[W][H];
 
 void draw(int x, int y, int idx) {
-  if (x >= 0 && x < W && y >= 0 && y < H) {
-    canvas[x][y] = palette[idx];
+  if (x >= 0 && y >= 0 && x < W && y < H) {
+//    _draw_p(x, y, palette[idx]);
+    canvas[x][y] = idx;
   }
 }