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AmigActive 10
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AACD 10.iso
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vidhrdw
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mikie.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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186 lines
/***************************************************************************
vidhrdw.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
#include "vidhrdw/generic.h"
static int palettebank,flipscreen;
/***************************************************************************
Convert the color PROMs into a more useable format.
Mikie has three 256x4 palette PROMs (one per gun) and two 256x4 lookup
table PROMs (one for characters, one for sprites).
I don't know for sure how the palette PROMs are connected to the RGB
output, but it's probably the usual:
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 mikie_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])
for (i = 0;i < Machine->drv->total_colors;i++)
{
int bit0,bit1,bit2,bit3;
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;
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;
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 character lookup table */
/* there are eight 32 colors palette banks; sprites use colors 0-15 and */
/* characters 16-31 of each bank. */
for (i = 0;i < TOTAL_COLORS(0)/8;i++)
{
int j;
for (j = 0;j < 8;j++)
COLOR(0,i + j * TOTAL_COLORS(0)/8) = (*color_prom & 0x0f) + 32 * j + 16;
color_prom++;
}
for (i = 0;i < TOTAL_COLORS(1)/8;i++)
{
int j;
for (j = 0;j < 8;j++)
COLOR(1,i + j * TOTAL_COLORS(1)/8) = (*color_prom & 0x0f) + 32 * j;
color_prom++;
}
}
WRITE_HANDLER( mikie_palettebank_w )
{
if (palettebank != (data & 7))
{
palettebank = data & 7;
memset(dirtybuffer,1,videoram_size);
}
}
WRITE_HANDLER( mikie_flipscreen_w )
{
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 mikie_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 - 1;offs >= 0;offs--)
{
int sx,sy,flipx,flipy;
if (dirtybuffer[offs])
{
dirtybuffer[offs] = 0;
sx = offs % 32;
sy = offs / 32;
flipx = colorram[offs] & 0x40;
flipy = colorram[offs] & 0x80;
if (flipscreen)
{
sx = 31 - sx;
sy = 31 - sy;
flipx = !flipx;
flipy = !flipy;
}
drawgfx(tmpbitmap,Machine->gfx[0],
videoram[offs] + ((colorram[offs] & 0x20) << 3),
(colorram[offs] & 0x0f) + 16 * palettebank,
flipx,flipy,
8*sx,8*sy,
&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
}
}
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,flipx,flipy;
sx = spriteram[offs + 3];
sy = 244 - spriteram[offs + 1];
flipx = ~spriteram[offs] & 0x10;
flipy = spriteram[offs] & 0x20;
if (flipscreen)
{
sy = 242 - sy;
flipy = !flipy;
}
drawgfx(bitmap,Machine->gfx[(spriteram[offs+2] & 0x40) ? 2 : 1],
(spriteram[offs + 2] & 0x3f) + ((spriteram[offs + 2] & 0x80) >> 1)
+ ((spriteram[offs] & 0x40) << 1),
(spriteram[offs] & 0x0f) + 16 * palettebank,
flipx,flipy,
sx,sy,
&Machine->drv->visible_area,TRANSPARENCY_PEN,0);
}
}