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AmigActive 10
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AACD 10.iso
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vidhrdw
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bankp.c
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C/C++ Source or Header
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2000-04-04
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7KB
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283 lines
/***************************************************************************
vidhrdw.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
#include "vidhrdw/generic.h"
unsigned char *bankp_videoram2;
unsigned char *bankp_colorram2;
static unsigned char *dirtybuffer2;
static struct osd_bitmap *tmpbitmap2;
static int scroll_x;
static int flipscreen;
static int priority;
/***************************************************************************
Convert the color PROMs into a more useable format.
Bank Panic has a 32x8 palette PROM (I'm not sure whether the second 16
bytes are used - they contain the same colors as the first 16 with only
one different) and two 256x4 lookup table PROMs (one for charset #1, one
for charset #2 - only the first 128 nibbles seem to be used).
I don't know for sure how the palette PROM is connected to the RGB output,
but it's probably the usual:
bit 7 -- 220 ohm resistor -- BLUE
-- 470 ohm resistor -- BLUE
-- 220 ohm resistor -- GREEN
-- 470 ohm resistor -- GREEN
-- 1 kohm resistor -- GREEN
-- 220 ohm resistor -- RED
-- 470 ohm resistor -- RED
bit 0 -- 1 kohm resistor -- RED
***************************************************************************/
void bankp_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;
/* red component */
bit0 = (*color_prom >> 0) & 0x01;
bit1 = (*color_prom >> 1) & 0x01;
bit2 = (*color_prom >> 2) & 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 = 0;
bit1 = (*color_prom >> 6) & 0x01;
bit2 = (*color_prom >> 7) & 0x01;
*(palette++) = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
color_prom++;
}
/* color_prom now points to the beginning of the lookup table */
/* charset #1 lookup table */
for (i = 0;i < TOTAL_COLORS(0);i++)
COLOR(0,i) = *(color_prom++) & 0x0f;
color_prom += 128; /* skip the bottom half of the PROM - seems to be not used */
/* charset #2 lookup table */
for (i = 0;i < TOTAL_COLORS(1);i++)
COLOR(1,i) = *(color_prom++) & 0x0f;
/* the bottom half of the PROM seems to be not used */
}
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
int bankp_vh_start(void)
{
if (generic_vh_start() != 0)
return 1;
if ((dirtybuffer2 = malloc(videoram_size)) == 0)
{
generic_vh_stop();
return 1;
}
memset(dirtybuffer2,1,videoram_size);
if ((tmpbitmap2 = osd_create_bitmap(Machine->drv->screen_width,Machine->drv->screen_height)) == 0)
{
free(dirtybuffer2);
generic_vh_stop();
return 1;
}
return 0;
}
WRITE_HANDLER( bankp_scroll_w )
{
scroll_x = data;
}
/***************************************************************************
Stop the video hardware emulation.
***************************************************************************/
void bankp_vh_stop(void)
{
free(dirtybuffer2);
osd_free_bitmap(tmpbitmap2);
generic_vh_stop();
}
WRITE_HANDLER( bankp_videoram2_w )
{
if (bankp_videoram2[offset] != data)
{
dirtybuffer2[offset] = 1;
bankp_videoram2[offset] = data;
}
}
WRITE_HANDLER( bankp_colorram2_w )
{
if (bankp_colorram2[offset] != data)
{
dirtybuffer2[offset] = 1;
bankp_colorram2[offset] = data;
}
}
WRITE_HANDLER( bankp_out_w )
{
/* bits 0-1 are playfield priority */
/* TODO: understand how this works, currently the only thing I do is */
/* invert the layer order when priority == 2 */
priority = data & 0x03;
/* bits 2-3 unknown (2 is used) */
/* bit 4 controls NMI */
if (data & 0x10) interrupt_enable_w(0,1);
else interrupt_enable_w(0,0);
/* bit 5 controls screen flip */
if ((data & 0x20) != flipscreen)
{
flipscreen = data & 0x20;
memset(dirtybuffer,1,videoram_size);
memset(dirtybuffer2,1,videoram_size);
}
/* bits 6-7 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 bankp_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--)
{
if (dirtybuffer[offs])
{
int sx,sy,flipx;
dirtybuffer[offs] = 0;
sx = offs % 32;
sy = offs / 32;
flipx = colorram[offs] & 0x04;
if (flipscreen)
{
sx = 31 - sx;
sy = 31 - sy;
flipx = !flipx;
}
drawgfx(tmpbitmap,Machine->gfx[0],
videoram[offs] + 256 * ((colorram[offs] & 3) >> 0),
colorram[offs] >> 3,
flipx,flipscreen,
8*sx,8*sy,
0,TRANSPARENCY_NONE,0);
}
if (dirtybuffer2[offs])
{
int sx,sy,flipx;
dirtybuffer2[offs] = 0;
sx = offs % 32;
sy = offs / 32;
flipx = bankp_colorram2[offs] & 0x08;
if (flipscreen)
{
sx = 31 - sx;
sy = 31 - sy;
flipx = !flipx;
}
drawgfx(tmpbitmap2,Machine->gfx[1],
bankp_videoram2[offs] + 256 * (bankp_colorram2[offs] & 0x07),
bankp_colorram2[offs] >> 4,
flipx,flipscreen,
8*sx,8*sy,
&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
}
}
/* copy the temporary bitmaps to the screen */
{
int scroll;
scroll = -scroll_x;
if (priority == 2)
{
copyscrollbitmap(bitmap,tmpbitmap,1,&scroll,0,0,&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
copybitmap(bitmap,tmpbitmap2,0,0,0,0,&Machine->drv->visible_area,TRANSPARENCY_COLOR,0);
}
else
{
copybitmap(bitmap,tmpbitmap2,0,0,0,0,&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
copyscrollbitmap(bitmap,tmpbitmap,1,&scroll,0,0,&Machine->drv->visible_area,TRANSPARENCY_COLOR,0);
}
}
}