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vidhrdw
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yard.c
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C/C++ Source or Header
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2000-04-04
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9KB
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380 lines
/***************************************************************************
vidhrdw.c
10 Yard Fight
L Taylor
J Clegg
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
#include "vidhrdw/generic.h"
unsigned char *yard_scroll_x_low;
unsigned char *yard_scroll_x_high;
unsigned char *yard_scroll_y_low;
unsigned char *yard_score_panel_disabled;
static int flipscreen;
static struct osd_bitmap *scroll_panel_bitmap;
#define SCROLL_PANEL_WIDTH (14*4)
#define RADAR_PALETTE_BASE (256+16)
static struct rectangle panelvisiblearea =
{
26*8, 32*8-1,
1*8, 31*8-1
};
static struct rectangle panelvisibleareaflip =
{
0*8, 6*8-1,
1*8, 31*8-1
};
/***************************************************************************
Convert the color PROMs into a more useable format.
10 Yard Fight has two 256x4 character palette PROMs, one 32x8 sprite
palette PROM, one 256x4 sprite color lookup table PROM, and two 256x4
radar palette PROMs.
I don't know for sure how the palette PROMs are connected to the RGB
output, but it's probably something like this; note that RED and BLUE
are swapped wrt the usual configuration.
bit 7 -- 220 ohm resistor -- RED
-- 470 ohm resistor -- RED
-- 220 ohm resistor -- GREEN
-- 470 ohm resistor -- GREEN
-- 1 kohm resistor -- GREEN
-- 220 ohm resistor -- BLUE
-- 470 ohm resistor -- BLUE
bit 0 -- 1 kohm resistor -- BLUE
***************************************************************************/
void yard_vh_convert_color_prom(unsigned char *palette, unsigned short *colortable,const unsigned char *color_prom)
{
int i;
#define TOTAL_COLORS(gfxn) (Machine->gfx[gfxn]->total_colors * Machine->gfx[gfxn]->color_granularity)
#define COLOR(gfxn,offs) (colortable[Machine->drv->gfxdecodeinfo[gfxn].color_codes_start + offs])
/* character palette */
for (i = 0;i < 256;i++)
{
int bit0,bit1,bit2;
/* red component */
bit0 = 0;
bit1 = (color_prom[256] >> 2) & 0x01;
bit2 = (color_prom[256] >> 3) & 0x01;
*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = (color_prom[0] >> 3) & 0x01;
bit1 = (color_prom[256] >> 0) & 0x01;
bit2 = (color_prom[256] >> 1) & 0x01;
*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = (color_prom[0] >> 0) & 0x01;
bit1 = (color_prom[0] >> 1) & 0x01;
bit2 = (color_prom[0] >> 2) & 0x01;
*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
color_prom++;
}
color_prom += 256;
/* color_prom now points to the beginning of the sprite palette */
/* sprite palette */
for (i = 0;i < 16;i++)
{
int bit0,bit1,bit2;
/* red component */
bit0 = 0;
bit1 = (*color_prom >> 6) & 0x01;
bit2 = (*color_prom >> 7) & 0x01;
*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = (*color_prom >> 3) & 0x01;
bit1 = (*color_prom >> 4) & 0x01;
bit2 = (*color_prom >> 5) & 0x01;
*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = (*color_prom >> 0) & 0x01;
bit1 = (*color_prom >> 1) & 0x01;
bit2 = (*color_prom >> 2) & 0x01;
*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
color_prom++;
}
color_prom += 16;
/* color_prom now points to the beginning of the sprite lookup table */
/* sprite lookup table */
for (i = 0;i < TOTAL_COLORS(1);i++)
COLOR(1,i) = 256 + (*(color_prom++) & 0x0f);
/* color_prom now points to the beginning of the radar palette */
/* radar palette */
for (i = 0;i < 256;i++)
{
int bit0,bit1,bit2;
/* red component */
bit0 = 0;
bit1 = (color_prom[256] >> 2) & 0x01;
bit2 = (color_prom[256] >> 3) & 0x01;
*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = (color_prom[0] >> 3) & 0x01;
bit1 = (color_prom[256] >> 0) & 0x01;
bit2 = (color_prom[256] >> 1) & 0x01;
*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = (color_prom[0] >> 0) & 0x01;
bit1 = (color_prom[0] >> 1) & 0x01;
bit2 = (color_prom[0] >> 2) & 0x01;
*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
color_prom++;
}
}
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
int yard_vh_start(void)
{
if ((dirtybuffer = malloc(videoram_size)) == 0)
return 1;
memset(dirtybuffer,1,videoram_size);
if ((tmpbitmap = osd_create_bitmap(Machine->drv->screen_width*2,Machine->drv->screen_height)) == 0)
{
free(dirtybuffer);
return 1;
}
if ((scroll_panel_bitmap = osd_create_bitmap(SCROLL_PANEL_WIDTH,Machine->drv->screen_height)) == 0)
{
free(dirtybuffer);
osd_free_bitmap(tmpbitmap);
return 1;
}
return 0;
}
/***************************************************************************
Stop the video hardware emulation.
***************************************************************************/
void yard_vh_stop(void)
{
free(dirtybuffer);
osd_free_bitmap(tmpbitmap);
osd_free_bitmap(scroll_panel_bitmap);
}
WRITE_HANDLER( yard_flipscreen_w )
{
/* 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);
}
coin_counter_w(0,data & 0x02);
coin_counter_w(1,data & 0x20);
}
WRITE_HANDLER( yard_scroll_panel_w )
{
int sx,sy,i;
sx = ( offset % 16 );
sy = ( offset / 16 );
if (sx < 1 || sx > 14) return;
sx = 4 * (sx - 1);
for (i = 0;i < 4;i++)
{
int col;
col = (data >> i) & 0x11;
col = ((col >> 3) | col) & 3;
plot_pixel(scroll_panel_bitmap, sx + i, sy, Machine->pens[RADAR_PALETTE_BASE + (sy & 0xfc) + col]);
}
}
/***************************************************************************
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 yard_vh_screenrefresh(struct osd_bitmap *bitmap,int full_refresh)
{
int offs;
/* for every character in the Video RAM, check if it has been modified */
/* since last time and update it accordingly. */
for (offs = videoram_size-2;offs >= 0;offs -= 2)
{
if (dirtybuffer[offs] || dirtybuffer[offs+1])
{
int sx,sy,flipx;
dirtybuffer[offs] = 0;
dirtybuffer[offs+1] = 0;
sx = (offs/2) % 32;
sy = (offs/2) / 32;
flipx = videoram[offs+1] & 0x20;
if (sy >= 32)
{
sy -= 32;
sx += 32;
}
if (flipscreen)
{
sx = 63 - sx;
sy = 31 - sy;
flipx = !flipx;
}
drawgfx(tmpbitmap,Machine->gfx[0],
videoram[offs] + ((videoram[offs+1] & 0xc0) << 2),
videoram[offs+1] & 0x1f,
flipx,flipscreen,
8*sx,8*sy,
0,TRANSPARENCY_NONE,0);
}
}
/* copy the temporary bitmap to the screen */
{
int scroll_x,scroll_y;
scroll_x = (*yard_scroll_x_high * 0x100) + *yard_scroll_x_low;
if (flipscreen)
{
scroll_x += 256;
scroll_y = *yard_scroll_y_low ;
}
else
{
scroll_x = -scroll_x;
scroll_y = -*yard_scroll_y_low ;
}
copyscrollbitmap(bitmap,tmpbitmap,1,&scroll_x,1,&scroll_y,&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
}
for (offs = spriteram_size - 4;offs >= 0;offs -= 4)
{
int code1,code2,bank,sx,sy1,sy2,flipx,flipy;
bank = (spriteram[offs + 1] & 0x20) >> 5;
code1 = spriteram[offs + 2] & 0xbf;
sx = spriteram[offs + 3];
sy1 = 241 - spriteram[offs];
flipx = spriteram[offs + 1] & 0x40;
flipy = spriteram[offs + 1] & 0x80;
if (flipy)
{
code2 = code1;
code1 += 0x40;
}
else
{
code2 = code1 + 0x40;
}
if (flipscreen)
{
flipx = !flipx;
flipy = !flipy;
sx = 240 - sx;
sy2 = 224 - sy1;
sy1 = sy2 + 0x10;
}
else
{
sy2 = sy1 + 0x10;
}
drawgfx(bitmap,Machine->gfx[1],
code1 + 256 * bank,
spriteram[offs + 1] & 0x1f,
flipx,flipy,
sx, sy1,
&Machine->drv->visible_area,TRANSPARENCY_COLOR,256);
drawgfx(bitmap,Machine->gfx[1],
code2 + 256 * bank,
spriteram[offs + 1] & 0x1f,
flipx,flipy,
sx, sy2,
&Machine->drv->visible_area,TRANSPARENCY_COLOR,256);
}
/* draw the static bitmapped area to screen */
if (! *yard_score_panel_disabled)
{
int xpos;
xpos = flipscreen ? Machine->drv->visible_area.min_x - 8 :
Machine->drv->visible_area.max_x + 1 - SCROLL_PANEL_WIDTH;
copybitmap(bitmap,scroll_panel_bitmap,flipscreen,flipscreen,
xpos,0,
flipscreen ? &panelvisibleareaflip : &panelvisiblearea,TRANSPARENCY_NONE,0);
}
}