home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
AmigActive 10
/
AACD 10.iso
/
AACD
/
Games
/
MAME
/
src
/
vidhrdw
/
amidar.c
< prev
next >
Wrap
C/C++ Source or Header
|
2000-04-04
|
5KB
|
206 lines
/***************************************************************************
vidhrdw.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
#include "vidhrdw/generic.h"
unsigned char *amidar_attributesram;
static int flipscreen[2];
static struct rectangle spritevisiblearea =
{
2*8+1, 32*8-1,
2*8, 30*8-1
};
static struct rectangle spritevisibleareaflipx =
{
0*8, 30*8-2,
2*8, 30*8-1
};
/***************************************************************************
Convert the color PROMs into a more useable format.
Amidar has one 32 bytes palette PROM, connected to the RGB output this
way:
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 amidar_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 = (*color_prom >> 6) & 0x01;
bit1 = (*color_prom >> 7) & 0x01;
*(palette++) = 0x4f * bit0 + 0xa8 * bit1;
color_prom++;
}
/* characters and sprites use the same palette */
for (i = 0;i < TOTAL_COLORS(0);i++)
{
if (i & 3) COLOR(0,i) = i;
else COLOR(0,i) = 0; /* 00 is always black, regardless of the contents of the PROM */
}
}
WRITE_HANDLER( amidar_flipx_w )
{
if (flipscreen[0] != (data & 1))
{
flipscreen[0] = data & 1;
memset(dirtybuffer,1,videoram_size);
}
}
WRITE_HANDLER( amidar_flipy_w )
{
if (flipscreen[1] != (data & 1))
{
flipscreen[1] = data & 1;
memset(dirtybuffer,1,videoram_size);
}
}
WRITE_HANDLER( amidar_attributes_w )
{
if ((offset & 1) && amidar_attributesram[offset] != data)
{
int i;
for (i = offset / 2;i < videoram_size;i += 32)
dirtybuffer[i] = 1;
}
amidar_attributesram[offset] = data;
}
/***************************************************************************
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 amidar_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;
dirtybuffer[offs] = 0;
sx = offs % 32;
sy = offs / 32;
if (flipscreen[0]) sx = 31 - sx;
if (flipscreen[1]) sy = 31 - sy;
drawgfx(tmpbitmap,Machine->gfx[0],
videoram[offs],
amidar_attributesram[2 * (offs % 32) + 1] & 0x07,
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. Note that it is important to draw them exactly in this */
/* order, to have the correct priorities. */
for (offs = spriteram_size - 4;offs >= 0;offs -= 4)
{
int flipx,flipy,sx,sy;
sx = (spriteram[offs + 3] + 1) & 0xff; /* ??? */
sy = 240 - spriteram[offs];
flipx = spriteram[offs + 1] & 0x40;
flipy = spriteram[offs + 1] & 0x80;
if (flipscreen[0])
{
sx = 241 - sx; /* note: 241, not 240 */
flipx = !flipx;
}
if (flipscreen[1])
{
sy = 240 - sy;
flipy = !flipy;
}
/* Sprites #0, #1 and #2 need to be offset one pixel to be correctly */
/* centered on the ladders in Turtles (we move them down, but since this */
/* is a rotated game, we actually move them left). */
/* Note that the adjustement must be done AFTER handling flipscreen, thus */
/* proving that this is a hardware related "feature" */
if (offs <= 2*4) sy++;
drawgfx(bitmap,Machine->gfx[1],
spriteram[offs + 1] & 0x3f,
spriteram[offs + 2] & 0x07,
flipx,flipy,
sx,sy,
flipscreen[0] ? &spritevisibleareaflipx : &spritevisiblearea,TRANSPARENCY_PEN,0);
}
}