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AmigActive 10
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AACD 10.iso
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vidhrdw
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milliped.c
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C/C++ Source or Header
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2000-04-04
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178 lines
/***************************************************************************
vidhrdw.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
#include "vidhrdw/generic.h"
static struct rectangle spritevisiblearea =
{
1*8, 31*8-1,
0*8, 30*8-1
};
/***************************************************************************
Millipede doesn't have a color PROM, it uses RAM.
The RAM seems to be conncted to the video output this way:
bit 7 red
red
red
green
green
blue
blue
bit 0 blue
***************************************************************************/
WRITE_HANDLER( milliped_paletteram_w )
{
int bit0,bit1,bit2;
int r,g,b;
paletteram[offset] = data;
/* red component */
bit0 = (~data >> 5) & 0x01;
bit1 = (~data >> 6) & 0x01;
bit2 = (~data >> 7) & 0x01;
r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = 0;
bit1 = (~data >> 3) & 0x01;
bit2 = (~data >> 4) & 0x01;
g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = (~data >> 0) & 0x01;
bit1 = (~data >> 1) & 0x01;
bit2 = (~data >> 2) & 0x01;
b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
palette_change_color(offset,r,g,b);
}
/***************************************************************************
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 milliped_vh_screenrefresh(struct osd_bitmap *bitmap,int full_refresh)
{
int offs;
if (palette_recalc() || full_refresh)
memset (dirtybuffer, 1, videoram_size);
/* 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;
int bank;
int color;
dirtybuffer[offs] = 0;
sx = offs % 32;
sy = offs / 32;
if (videoram[offs] & 0x40)
bank = 1;
else bank = 0;
if (videoram[offs] & 0x80)
color = 2;
else color = 0;
drawgfx(bitmap,Machine->gfx[0],
0x40 + (videoram[offs] & 0x3f) + 0x80 * bank,
bank + color,
0,0,
8*sx,8*sy,
&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
}
}
/* Draw the sprites */
for (offs = 0;offs < 0x10;offs++)
{
int spritenum,color;
int x, y;
int sx, sy;
x = spriteram[offs + 0x20];
y = 240 - spriteram[offs + 0x10];
spritenum = spriteram[offs] & 0x3f;
if (spritenum & 1) spritenum = spritenum / 2 + 64;
else spritenum = spritenum / 2;
/* Millipede is unusual because the sprite color code specifies the */
/* colors to use one by one, instead of a combination code. */
/* bit 7-6 = palette bank (there are 4 groups of 4 colors) */
/* bit 5-4 = color to use for pen 11 */
/* bit 3-2 = color to use for pen 10 */
/* bit 1-0 = color to use for pen 01 */
/* pen 00 is transparent */
color = spriteram[offs + 0x30];
Machine->gfx[1]->colortable[3] =
Machine->pens[16+((color >> 4) & 3)+4*((color >> 6) & 3)];
Machine->gfx[1]->colortable[2] =
Machine->pens[16+((color >> 2) & 3)+4*((color >> 6) & 3)];
Machine->gfx[1]->colortable[1] =
Machine->pens[16+((color >> 0) & 3)+4*((color >> 6) & 3)];
drawgfx(bitmap,Machine->gfx[1],
spritenum,
0,
0,spriteram[offs] & 0x80,
x,y,
&spritevisiblearea,TRANSPARENCY_PEN,0);
/* mark tiles underneath as dirty */
sx = x >> 3;
sy = y >> 3;
{
int max_x = 1;
int max_y = 2;
int x2, y2;
if (x & 0x07) max_x ++;
if (y & 0x0f) max_y ++;
for (y2 = sy; y2 < sy + max_y; y2 ++)
{
for (x2 = sx; x2 < sx + max_x; x2 ++)
{
if ((x2 < 32) && (y2 < 32) && (x2 >= 0) && (y2 >= 0))
dirtybuffer[x2 + 32*y2] = 1;
}
}
}
}
}