nes: fixed presets, added to platforms menu

doc/notes.txt

@@ -96,6 +96,7 @@ TODO:
 - open ROM from URL?
 - NES: disassembly not aligned on PC
 - NES: vrambuf.c for Solarian
+- game starts even if switched away before first load
 
 
 WEB WORKER FORMAT

index.html

@@ -109,6 +109,7 @@ if (window.location.host.endsWith('8bitworkshop.com')) {
              <ul class="dropdown-menu">
                <li><a class="dropdown-item" href="?platform=vcs" id="item_platform_vcs">Atari 2600/VCS</a></li>
                <li><a class="dropdown-item" href="?platform=vcs.mame" id="item_platform_vcs">Atari 2600/VCS (MAME)</a></li>
+               <li><a class="dropdown-item" href="?platform=nes" id="item_platform_nes">NES</a></li>
              </ul>
           </li>
           <li class="dropdown dropdown-submenu">

presets/nes/climber.c

@@ -78,10 +78,6 @@ byte rndint(byte a, byte b) {
   return (rand() % (b-a)) + a;
 }
 
-///// OAM buffer (for sprites)
-
-#define OAMBUF ((unsigned char*) 0x200)
-
 // return nametable address for tile (x,y)
 // assuming vertical scrolling (horiz. mirroring)
 word getntaddr(byte x, byte y) {
@@ -397,6 +393,7 @@ void create_actors_on_floor(byte floor_index) {
     if (floor_index == MAX_FLOORS-1) {
       a->name = ACTOR_RESCUE;
       a->state = PACING;
+      a->x = 0;
     }
   }
 }
@@ -439,14 +436,15 @@ byte draw_actor(byte oam_id, byte i) {
   x = a->x;
   y = screen_y;
   oam_id = oam_meta_spr(x, y, oam_id, meta);
-  // actor 0 is player sprite
+  // is this actor 0? (player sprite)
   if (i == 0) {
     player_screen_y = y; // last screen Y position
-    // set special palette for player sprites
+    // set special palette for the player's sprites
-    OAMBUF[0+2] |= 3;
+    // directly in OAM buffer
-    OAMBUF[4+2] |= 3;
+    OAMBUF[0].attr |= 3;
-    OAMBUF[8+2] |= 3;
+    OAMBUF[1].attr |= 3;
-    OAMBUF[12+2] |= 3;
+    OAMBUF[2].attr |= 3;
+    OAMBUF[3].attr |= 3;
   }
   a->onscreen = 1;
   return oam_id;

presets/nes/ex1.asm

@@ -38,7 +38,7 @@ Start:
 ; fill video RAM with "Hello World" msg
 HelloVRAM: subroutine
 ; set PPU address to name table A (row 1, col 1)
-	PPU_SETADDR	$2021
+	PPU_SETADDR $2021
 	ldy #0		; set Y counter to 0
 .loop:
 	lda HelloMsg,y	; get next character
@@ -57,7 +57,8 @@ HelloMsg:
 ; set palette colors
 SetPalette: subroutine
 ; set PPU address to palette start
-	PPU_SETADDR	$3f00
+	PPU_SETADDR $3f00
+        ldy #0
 .loop:
 	lda Palette,y	; lookup byte in ROM
 	sta PPU_DATA	; store byte to PPU data

presets/nes/ex2.asm

@@ -10,7 +10,7 @@ ScrollPos	word	; used during NMI
 
 ;;;;; NES CARTRIDGE HEADER
 
-	NES_HEADER 0,2,1,1 ; mapper 0, 2 PRGs, 1 CHR, horiz. mirror
+	NES_HEADER 0,2,1,1 ; mapper 0, 2 PRGs, 1 CHR, vert. mirror
 
 ;;;;; START OF CODE
 
@@ -54,6 +54,7 @@ FillVRAM: subroutine
 ; set palette colors
 SetPalette: subroutine
 	PPU_SETADDR $3f00
+        ldy #0
 .loop:
 	lda Palette,y	; lookup byte in ROM
 	sta PPU_DATA	; store byte to PPU data

presets/nes/ex3.asm

@@ -45,6 +45,7 @@ Start:
 FillVRAM: subroutine
 	PPU_SETADDR $2000
 	ldy #$10
+        ldx #0
 .loop:
 	stx PPU_DATA	; X -> PPU data port
 	inx		; X = X + 1
@@ -83,6 +84,7 @@ MoveSprites: subroutine
 ; set palette colors
 SetPalette: subroutine
 	PPU_SETADDR $3f00
+        ldy #0
 .loop:
 	lda Palette,y	; lookup byte in ROM
 	sta PPU_DATA	; store byte to PPU data

presets/nes/ex4.asm

@@ -38,8 +38,9 @@ Start:
 
 ; fill video RAM
 FillVRAM: subroutine
-	PPU_SETADDR	$2000
+	PPU_SETADDR $2000
 	ldy #$10
+        ldx #0
 .loop:
 	stx PPU_DATA
 	inx
@@ -49,17 +50,16 @@ FillVRAM: subroutine
         rts
 
 ; set palette colors
-
 SetPalette: subroutine
-	PPU_SETADDR	$3f00
+	PPU_SETADDR $3f00
-	ldx #32
+        ldy #0
 .loop:
-	lda Palette,y
+	lda Palette,y	; lookup byte in ROM
-	sta PPU_DATA
+	sta PPU_DATA	; store byte to PPU data
-        iny
+        iny		; Y = Y + 1
-	dex
+        cpy #32		; is Y equal to 32?
-	bne .loop
+	bne .loop	; not yet, loop
-        rts
+        rts		; return to caller
 
 
 ;;;;; COMMON SUBROUTINES

presets/nes/metacursor.c

@@ -92,9 +92,6 @@ char actor_y[NUM_ACTORS];
 char actor_dx[NUM_ACTORS];
 char actor_dy[NUM_ACTORS];
 
-// OAM buffer pointer, in case we want to manipulate directly
-#define OAMBUF ((unsigned char*) 0x200)
-
 // main program
 void main() {
   char i;

presets/nes/metatrigger.c

@@ -92,9 +92,6 @@ char actor_y[NUM_ACTORS];
 char actor_dx[NUM_ACTORS];
 char actor_dy[NUM_ACTORS];
 
-// OAM buffer pointer, in case we want to manipulate directly
-#define OAMBUF ((unsigned char*) 0x200)
-
 // main program
 void main() {
   char i;
@@ -138,6 +135,11 @@ void main() {
       actor_x[i] += actor_dx[i];
       actor_y[i] += actor_dy[i];
     }
+    // set sprites 0-3 palette directly in OAM buffer
+    OAMBUF[0].attr |= 3;
+    OAMBUF[1].attr |= 3;
+    OAMBUF[2].attr |= 3;
+    OAMBUF[3].attr |= 3;
     // hide rest of sprites
     // if we haven't wrapped oam_id around to 0
     if (oam_id!=0) oam_hide_rest(oam_id);

presets/nes/neslib.h

@@ -42,7 +42,6 @@ typedef unsigned short word;	// 16-bit signed
 typedef enum { false, true } bool;	// boolean
 
 
-
 // set bg and spr palettes, data is 32 bytes array
 void __fastcall__ pal_all(const char *data);
 
@@ -309,5 +308,16 @@ void __fastcall__ nmi_set_callback(void (*callback)(void));
 #define MSB(x)			(((x)>>8))
 #define LSB(x)			(((x)&0xff))
 
+// OAM buffer @ $200-$2FF
+
+typedef struct OAMSprite {
+  byte y;	// Y coordinate
+  byte name;	// tile index in name table
+  byte attr;	// attribute flags
+  byte x;	// X coordinate
+} OAMSprite;
+
+#define OAMBUF			((OAMSprite*) 0x200)
+
 #endif /* neslib.h */
 

presets/nes/shoot2.c

@@ -692,25 +692,19 @@ void set_sounds() {
   APU_ENABLE(enable);
 }
 
-static char starx[32];	// array of star X coords
-static byte starofs;	// Y offset of all stars
-
 void init_stars() {
+  byte oamid = 0; // 32 slots = 128 bytes
   byte i;
-  for (i=0; i<sizeof(starx); i++) {
+  for (i=0; i<32; i++) {
-    starx[i] = rand();
+    oamid = oam_spr(rand(), i*8, 103+(i&3), 0, oamid);
   }
 }
 
 void draw_stars() {
   byte i;
-  byte oamid = 0; // 32 slots = 128 bytes
-  byte yofs = starofs;
   for (i=0; i<32; i++) {
-    oamid = oam_spr(starx[i], yofs, 102+(i&3), 0, oamid);
+    ++OAMBUF[i].y;
-    yofs += 8; // 32*8 = 256, wraps around
   }
-  starofs++;
 }
 
 void play_round() {
@@ -812,13 +806,13 @@ void setup_graphics() {
 void main() {  
   setup_graphics();
   apu_init();
-  init_stars();
   player_score = 0;
   while (1) {
     pal_all(PALETTE);
     oam_clear();
     oam_size(1); // 8x16 sprites
     clrscr();
+    init_stars();
     play_round();
   }
 }

presets/nes/vrambuf.c

@@ -2,15 +2,9 @@
 #include "neslib.h"
 #include "vrambuf.h"
 
-#pragma bss-name(push,"ZEROPAGE")
-#pragma data-name(push,"ZEROPAGE")
-
 // index to end of buffer
 byte updptr = 0;
 
-#pragma bss-name(pop)
-#pragma data-name(pop)
-
 // add EOF marker to buffer
 void cendbuf(void) {
   updbuf[updptr] = NT_UPD_EOF;
@@ -35,13 +29,18 @@ void cflushnow(void) {
 // add multiple characters to update buffer
 // using horizontal increment
 void putbytes(word addr, const char* str, byte len) {
+  // if bytes won't fit, wait for vsync and flush buffer
   if (updptr >= VBUFSIZE-4-len) cflushnow();
+  // add vram address
   updbuf[updptr] = (addr >> 8) ^ NT_UPD_HORZ;
   updbuf[++updptr] = addr & 0xff;
+  // add length
   updbuf[++updptr] = len;
+  // add bytes
   while (len--) {
     	updbuf[++updptr] = *str++;
   }
   ++updptr;
+  // add EOF mark
   cendbuf();
 }