medlanes.c

这个是延伸mame的在wince平台下的游戏模拟器的代码

/*************************************************************
 *
 * Meadows Lanes video handler
 *
 *************************************************************/

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

extern	int medlanes_latches[32];

static  int overlay = 0;

/* scale a markers vertical position */
static  int vert_scale(int data)
{
    return (data & 3) + ((data & 4) ? 6 : 0) + ((data & ~7) >> 3) * VERT_CHR;
}

/* mark the character occupied by the left (0) or right (1) marker dirty */
void	medlanes_marker_dirty(int marker)
{
int x, y;
	if (marker)
	{
		x = MARKER_HORZ_ADJ + medlanes_latches[MARKER1_HORZ];
		y = MARKER_VERT_ADJ + vert_scale(medlanes_latches[MARKER1_VERT]);
	}
	else
	{
		x = MARKER_HORZ_ADJ + medlanes_latches[MARKER0_HORZ];
		y = MARKER_VERT_ADJ + vert_scale(medlanes_latches[MARKER0_VERT]);
    }
	if (x < 0 || x >= HORZ_RES * HORZ_CHR)
		return;
	if (y < 0 || y >= VERT_RES * VERT_CHR)
        return;
	/* mark all occupied character positions dirty */
    dirtybuffer[(y+0)/VERT_CHR * HORZ_RES + (x+0)/HORZ_CHR] = 1;
	dirtybuffer[(y+3)/VERT_CHR * HORZ_RES + (x+0)/HORZ_CHR] = 1;
	dirtybuffer[(y+0)/VERT_CHR * HORZ_RES + (x+3)/HORZ_CHR] = 1;
	dirtybuffer[(y+3)/VERT_CHR * HORZ_RES + (x+3)/HORZ_CHR] = 1;
}

/* plot a bitmap pattern (for displaying markers) */
static  void plot_pattern(int x, int y, int pattern)
{
int bit;
	if (y < 0 || y >= VERT_RES * VERT_CHR)
		return;
	for (bit = 0; bit < 3; bit++)
	{
		if (x+bit < 0 || x+bit >= HORZ_RES * HORZ_CHR)
			continue;
		if (!(pattern & (4 >> bit)))
			tmpbitmap->line[y][x+bit] = Machine->colortable[0];
	}
}

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

        if (overlay != (input_port_2_r(0) & 0x80))
        {
                overlay = input_port_2_r(0) & 0x80;
                memset(dirtybuffer, 1, videoram_size);
        }

        /* The first row of characters is invsisible */
		for (i = 0; i < (VERT_RES - 1) * HORZ_RES; i++)
        {
			if (dirtybuffer[i])
			{
			int 	x, y;

				dirtybuffer[i] = 0;

				x = i % HORZ_RES;
				y = i / HORZ_RES;

				x *= HORZ_CHR;
				y *= VERT_CHR;

				drawgfx(tmpbitmap,
						Machine->gfx[0],
						videoram[i],
						0,
						0,0, x,y,
						&Machine->drv->visible_area,
						TRANSPARENCY_NONE,0);
			}
        }

		{
		int x, y;
			x = MARKER_HORZ_ADJ + medlanes_latches[MARKER0_HORZ];
			y = MARKER_VERT_ADJ + vert_scale(medlanes_latches[MARKER0_VERT]);
			plot_pattern(x,y+0,0);
			plot_pattern(x,y+1,2);
			plot_pattern(x,y+2,0);
        }

		{
		int x, y;
			x = MARKER_HORZ_ADJ + medlanes_latches[MARKER1_HORZ];
			y = MARKER_VERT_ADJ + vert_scale(medlanes_latches[MARKER1_VERT]);
            plot_pattern(x,y+0,0);
			plot_pattern(x,y+1,0);
			plot_pattern(x,y+2,0);
        }
		copybitmap(bitmap,tmpbitmap,0,0,0,0,&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
}