superman.c

这个是延伸mame的在wince平台下的游戏模拟器的代码

/***************************************************************************

  vidhrdw/superman.c

  Functions to emulate the video hardware of the machine.

***************************************************************************/

#include "driver.h"

int supes_videoram_size;
int supes_attribram_size;

unsigned char *supes_videoram;
unsigned char *supes_attribram;

int superman_vh_start (void)
{
	return 0;
}

void superman_vh_stop (void)
{
}

/*************************************
 *
 *		Foreground RAM
 *
 *************************************/

void supes_attribram_w (int offset, int data)
{
   int oldword = READ_WORD (&supes_attribram[offset]);
   int newword = COMBINE_WORD (oldword, data);

   if (oldword != newword)
   {
		WRITE_WORD (&supes_attribram[offset], data);
   }
}

int supes_attribram_r (int offset)
{
   return READ_WORD (&supes_attribram[offset]);
}



/*************************************
 *
 *		Background RAM
 *
 *************************************/

void supes_videoram_w (int offset, int data)
{
   int oldword = READ_WORD (&supes_videoram[offset]);
   int newword = COMBINE_WORD (oldword, data);

   if (oldword != newword)
   {
		WRITE_WORD (&supes_videoram[offset], data);
   }
}

int supes_videoram_r (int offset)
{
   return READ_WORD (&supes_videoram[offset]);
}


void superman_update_palette (void)
{
	unsigned short palette_map[32]; /* range of color table is 0-31 */
	int i;

	memset (palette_map, 0, sizeof (palette_map));

	/* Find colors used in the background tile plane */
	for (i = 0; i < 0x400; i += 0x40)
	{
		int i2;

		for (i2 = i; i2 < (i + 0x40); i2 += 2)
		{
			int tile;
			int color;

			color = 0;

			tile = READ_WORD (&supes_videoram[0x800 + i2]) & 0x3fff;
			if (tile)
				color = READ_WORD (&supes_videoram[0xc00 + i2]) >> 11;

			palette_map[color] |= Machine->gfx[0]->pen_usage[tile];

		}
	}

	/* Find colors used in the sprite plane */
	for (i = 0x3fe; i >= 0; i -= 2)
	{
		int tile;
		int color;

		color = 0;

		tile = READ_WORD (&supes_videoram[i]) & 0x3fff;
		if (tile)
			color = READ_WORD (&supes_videoram[0x400 + i]) >> 11;

		palette_map[color] |= Machine->gfx[0]->pen_usage[tile];
	}

	/* Now tell the palette system about those colors */
	for (i = 0;i < 32;i++)
	{
		int usage = palette_map[i];
		int j;

		if (usage)
		{
			palette_used_colors[i * 16 + 0] = PALETTE_COLOR_TRANSPARENT;
			for (j = 1; j < 16; j++)
				if (palette_map[i] & (1 << j))
					palette_used_colors[i * 16 + j] = PALETTE_COLOR_USED;
				else
					palette_used_colors[i * 16 + j] = PALETTE_COLOR_UNUSED;
		}
		else
			memset(&palette_used_colors[i * 16],PALETTE_COLOR_UNUSED,16);
	}

	palette_recalc ();

}

void superman_vh_screenrefresh (struct osd_bitmap *bitmap, int full_refresh)
{
	int i;

	superman_update_palette ();

	osd_clearbitmap(bitmap);

	/* Refresh the background tile plane */
	for (i = 0; i < 0x400; i += 0x40)
	{
		int x1, y1;
		int i2;

		x1 = READ_WORD (&supes_attribram[0x408 + (i >> 1)]);
		y1 = READ_WORD (&supes_attribram[0x400 + (i >> 1)]);

		for (i2 = i; i2 < (i + 0x40); i2 += 2)
		{
			int tile;

			tile = READ_WORD (&supes_videoram[0x800 + i2]) & 0x3fff;
			if (tile)
			{
				int x, y;

				x = (        x1 + ((i2 & 0x03) << 3))  & 0x1ff;
				y = ((265 - (y1 - ((i2 & 0x3c) << 2))) &  0xff);

				{
					int flipx = READ_WORD (&supes_videoram[0x800 + i2]) & 0x4000;
					int flipy = READ_WORD (&supes_videoram[0x800 + i2]) & 0x8000;
					int color = READ_WORD (&supes_videoram[0xc00 + i2]) >> 11;

					/* Some tiles are transparent, e.g. the gate, so we use TRANSPARENCY_PEN */
					drawgfx(bitmap,Machine->gfx[0],
						tile,
						color,
						flipx,flipy,
						x,y,
						&Machine->drv->visible_area,
						TRANSPARENCY_PEN,0);
				}
			}
		}
	}

	/* Refresh the sprite plane */
	for (i = 0x3fe; i >= 0; i -= 2)
	{
		int sprite;

		sprite = READ_WORD (&supes_videoram[i]) & 0x3fff;
		if (sprite)
		{
			int x, y;

			x = (      READ_WORD (&supes_videoram [0x400 + i]))  & 0x1ff;
			y = (250 - READ_WORD (&supes_attribram[i        ]))  & 0xff;

			{
				int flipy = READ_WORD (&supes_videoram[i]) & 0x4000;
				int flipx = READ_WORD (&supes_videoram[i]) & 0x8000;
				int color = READ_WORD (&supes_videoram[0x400 + i]) >> 11;

				drawgfx(bitmap,Machine->gfx[0],
					sprite,
					color,
					flipx,flipy,
					x,y,
					&Machine->drv->visible_area,
					TRANSPARENCY_PEN,0);
			}
		}
	}
}