kungfum.c

这个是延伸mame的在wince平台下的游戏模拟器的代码

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

  vidhrdw.c

  Functions to emulate the video hardware of the machine.

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

#include "driver.h"
#include "vidhrdw/generic.h"



unsigned char *kungfum_scroll_low;
unsigned char *kungfum_scroll_high;
static int flipscreen;
static const unsigned char *sprite_height_prom;



static struct rectangle spritevisiblearea =
{
	0*8, 32*8-1,
	10*8, 32*8-1
};
static struct rectangle flipspritevisiblearea =
{
	0*8, 32*8-1,
	0*8, 22*8-1
};



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

  Convert the color PROMs into a more useable format.

  Kung Fu Master has a six 256x4 palette PROMs (one per gun; three for
  characters, three for sprites).
  I don't know the exact values of the resistors between the RAM and the
  RGB output. I assumed these values (the same as Commando)

  bit 3 -- 220 ohm resistor  -- RED/GREEN/BLUE
        -- 470 ohm resistor  -- RED/GREEN/BLUE
        -- 1  kohm resistor  -- RED/GREEN/BLUE
  bit 0 -- 2.2kohm resistor  -- RED/GREEN/BLUE

***************************************************************************/
void kungfum_vh_convert_color_prom(unsigned char *palette, unsigned short *colortable,const unsigned char *color_prom)
{
	int i;


	for (i = 0;i < Machine->drv->total_colors;i++)
	{
		int bit0,bit1,bit2,bit3;

		/* red component */
		bit0 = (color_prom[0] >> 0) & 0x01;
		bit1 = (color_prom[0] >> 1) & 0x01;
		bit2 = (color_prom[0] >> 2) & 0x01;
		bit3 = (color_prom[0] >> 3) & 0x01;
		*(palette++) =  0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
		/* green component */
		bit0 = (color_prom[Machine->drv->total_colors] >> 0) & 0x01;
		bit1 = (color_prom[Machine->drv->total_colors] >> 1) & 0x01;
		bit2 = (color_prom[Machine->drv->total_colors] >> 2) & 0x01;
		bit3 = (color_prom[Machine->drv->total_colors] >> 3) & 0x01;
		*(palette++) =  0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
		/* blue component */
		bit0 = (color_prom[2*Machine->drv->total_colors] >> 0) & 0x01;
		bit1 = (color_prom[2*Machine->drv->total_colors] >> 1) & 0x01;
		bit2 = (color_prom[2*Machine->drv->total_colors] >> 2) & 0x01;
		bit3 = (color_prom[2*Machine->drv->total_colors] >> 3) & 0x01;
		*(palette++) =  0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;

		color_prom++;
	}

	color_prom += 2*Machine->drv->total_colors;
	/* color_prom now points to the beginning of the sprite height table */

	sprite_height_prom = color_prom;	/* we'll need this at run time */
}



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

  Start the video hardware emulation.

***************************************************************************/
int kungfum_vh_start(void)
{
	if ((dirtybuffer = malloc(videoram_size)) == 0)
		return 1;
	memset(dirtybuffer,1,videoram_size);

	/* Kung Fu Master has a virtual screen twice as large as the visible screen */
	if ((tmpbitmap = osd_create_bitmap(2 * Machine->drv->screen_width,Machine->drv->screen_height)) == 0)
	{
		free(dirtybuffer);
		return 1;
	}

	return 0;
}



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

  Stop the video hardware emulation.

***************************************************************************/
void kungfum_vh_stop(void)
{
	free(dirtybuffer);
	osd_free_bitmap(tmpbitmap);
}



void kungfum_flipscreen_w(int offset,int data)
{
	/* screen flip is handled both by software and hardware */
	data ^= ~readinputport(4) & 1;

	if (flipscreen != (data & 1))
	{
		flipscreen = data & 1;
		memset(dirtybuffer,1,videoram_size);
	}
}



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

  Draw the game screen in the given osd_bitmap.
  Do NOT call osd_update_display() from this function, it will be called by
  the main emulation engine.

***************************************************************************/
void kungfum_vh_screenrefresh(struct osd_bitmap *bitmap,int full_refresh)
{
	int offs,i;


	/* for every character in the Video RAM, check if it has been modified */
	/* since last time and update it accordingly. */
	for (offs = videoram_size - 1;offs >= 0;offs--)
	{
		if (dirtybuffer[offs])
		{
			int sx,sy,flipx,flipy;


			dirtybuffer[offs] = 0;

			sx = offs % 64;
			sy = offs / 64;
			flipx = colorram[offs] & 0x20;
			flipy = 0;
			if (flipscreen)
			{
				sx = 63 - sx;
				sy = 31 - sy;
				flipx = !flipx;
				flipy = !flipy;
			}

			drawgfx(tmpbitmap,Machine->gfx[0],
					videoram[offs] + 4 * (colorram[offs] & 0xc0),
					colorram[offs] & 0x1f,
					flipx,flipy,
					8*sx,8*sy,
					0,TRANSPARENCY_NONE,0);
		}
	}


	/* copy the temporary bitmap to the screen */
	{
		int scroll[32];


		if (flipscreen)
		{
			for (i = 31;i > 25;i--)
				scroll[i] = -128;
			for (i = 25;i >= 0;i--)
				scroll[i] = (*kungfum_scroll_low + 256 * *kungfum_scroll_high) - 128;
		}
		else
		{
			for (i = 0;i < 6;i++)
				scroll[i] = -128;
			for (i = 6;i < 32;i++)
				scroll[i] = -(*kungfum_scroll_low + 256 * *kungfum_scroll_high) - 128;
		}

		copyscrollbitmap(bitmap,tmpbitmap,32,scroll,0,0,&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
	}


	/* Draw the sprites. */
	for (offs = 0;offs < spriteram_size;offs += 8)
	{
		int incr,code,col,flipx,flipy,sx,sy;


		code = spriteram[offs+4] + 256 * (spriteram[offs+5] & 0x03);

		if (code != 0)
		{
			col = spriteram[offs+0] & 0x1f;
			sx = 256 * (spriteram[offs+7] & 1) + spriteram[offs+6] - 128,
			sy = 256+128-15 - (256 * (spriteram[offs+3] & 1) + spriteram[offs+2]),
			flipx = spriteram[offs+5] & 0x40;
			flipy = spriteram[offs+5] & 0x80;

			i = sprite_height_prom[code / 32];
			if (i == 1)	/* double height */
			{
				code &= ~1;
				sy -= 16;
			}
			else if (i == 2)	/* quadruple height */
			{
				i = 3;
				code &= ~3;
				sy -= 3*16;
			}

			if (flipscreen)
			{
				sx = 240 - sx;
				sy = 242 - i*16 - sy;	/* sprites are slightly misplaced by the hardware */
				flipx = !flipx;
				flipy = !flipy;
			}

			if (flipy)
			{
				incr = -1;
				code += i;
			}
			else incr = 1;

			do
			{
				drawgfx(bitmap,Machine->gfx[1],
						code + i * incr,col,
						flipx,flipy,
						sx,sy + 16 * i,
						flipscreen ? &flipspritevisiblearea : &spritevisiblearea,TRANSPARENCY_PEN,0);

				i--;
			} while (i >= 0);
		}
	}
}