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AmigActive 10
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AACD 10.iso
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vidhrdw
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arkanoid.c
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C/C++ Source or Header
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2000-04-04
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5KB
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184 lines
/***************************************************************************
vidhrdw.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
#include "vidhrdw/generic.h"
static int flipscreen[2];
static int gfxbank,palettebank;
extern int arkanoid_paddle_select;
extern int arkanoid_coin_lockout;
/***************************************************************************
Convert the color PROMs into a more useable format.
Arkanoid has a three 512x4 palette PROMs (one per gun).
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 arkanoid_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++;
}
}
WRITE_HANDLER( arkanoid_d008_w )
{
/* bits 0 and 1 flip X and Y, I don't know which is which */
if (flipscreen[0] != (data & 0x01))
{
flipscreen[0] = data & 0x01;
memset(dirtybuffer,1,videoram_size);
}
if (flipscreen[1] != (data & 0x02))
{
flipscreen[1] = data & 0x02;
memset(dirtybuffer,1,videoram_size);
}
/* bit 2 selects the input paddle */
arkanoid_paddle_select = data & 0x04;
/* bit 3 is coin lockout (but not the service coin) */
coin_lockout_w(0, !(data & 0x08));
coin_lockout_w(1, !(data & 0x08));
/* bit 4 is unknown */
/* bits 5 and 6 control gfx bank and palette bank. They are used together */
/* so I don't know which is which. */
if (gfxbank != ((data & 0x20) >> 5))
{
gfxbank = (data & 0x20) >> 5;
memset(dirtybuffer,1,videoram_size);
}
if (palettebank != ((data & 0x40) >> 6))
{
palettebank = (data & 0x40) >> 6;
memset(dirtybuffer,1,videoram_size);
}
/* bit 7 is unknown */
}
/***************************************************************************
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 arkanoid_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)
{
int offs2;
offs2 = offs/2;
if (dirtybuffer[offs] || dirtybuffer[offs+1])
{
int sx,sy,code;
dirtybuffer[offs] = 0;
dirtybuffer[offs + 1] = 0;
sx = offs2 % 32;
sy = offs2 / 32;
if (flipscreen[0]) sx = 31 - sx;
if (flipscreen[1]) sy = 31 - sy;
code = videoram[offs + 1] + ((videoram[offs] & 0x07) << 8) + 2048 * gfxbank;
drawgfx(tmpbitmap,Machine->gfx[0],
code,
((videoram[offs] & 0xf8) >> 3) + 32 * palettebank,
flipscreen[0],flipscreen[1],
8*sx,8*sy,
&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
}
}
/* copy the temporary bitmap to the screen */
copybitmap(bitmap,tmpbitmap,0,0,0,0,&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
/* Draw the sprites. */
for (offs = 0;offs < spriteram_size;offs += 4)
{
int sx,sy,code;
sx = spriteram[offs];
sy = 248 - spriteram[offs + 1];
if (flipscreen[0]) sx = 248 - sx;
if (flipscreen[1]) sy = 248 - sy;
code = spriteram[offs + 3] + ((spriteram[offs + 2] & 0x03) << 8) + 1024 * gfxbank;
drawgfx(bitmap,Machine->gfx[0],
2 * code,
((spriteram[offs + 2] & 0xf8) >> 3) + 32 * palettebank,
flipscreen[0],flipscreen[1],
sx,sy + (flipscreen[1] ? 8 : -8),
&Machine->drv->visible_area,TRANSPARENCY_PEN,0);
drawgfx(bitmap,Machine->gfx[0],
2 * code + 1,
((spriteram[offs + 2] & 0xf8) >> 3) + 32 * palettebank,
flipscreen[0],flipscreen[1],
sx,sy,
&Machine->drv->visible_area,TRANSPARENCY_PEN,0);
}
}