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AmigActive 10
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vidhrdw
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vulgus.c
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C/C++ Source or Header
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2000-05-04
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7KB
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280 lines
/***************************************************************************
vidhrdw.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
#include "vidhrdw/generic.h"
unsigned char *vulgus_bgvideoram,*vulgus_bgcolorram;
size_t vulgus_bgvideoram_size;
unsigned char *vulgus_scrolllow,*vulgus_scrollhigh;
unsigned char *vulgus_palette_bank;
static unsigned char *dirtybuffer2;
static struct osd_bitmap *tmpbitmap2;
/***************************************************************************
Convert the color PROMs into a more useable format.
***************************************************************************/
void vulgus_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 lookup table */
/* characters use colors 32-47 (?) */
for (i = 0;i < TOTAL_COLORS(0);i++)
COLOR(0,i) = *(color_prom++) + 32;
/* sprites use colors 16-31 */
for (i = 0;i < TOTAL_COLORS(2);i++)
{
COLOR(2,i) = *(color_prom++) + 16;
}
/* background tiles use colors 0-15, 64-79, 128-143, 192-207 in four banks */
for (i = 0;i < TOTAL_COLORS(1)/4;i++)
{
COLOR(1,i) = *color_prom;
COLOR(1,i+32*8) = *color_prom + 64;
COLOR(1,i+2*32*8) = *color_prom + 128;
COLOR(1,i+3*32*8) = *color_prom + 192;
color_prom++;
}
}
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
int vulgus_vh_start(void)
{
if (generic_vh_start() != 0)
return 1;
if ((dirtybuffer2 = malloc(vulgus_bgvideoram_size)) == 0)
{
generic_vh_stop();
return 1;
}
memset(dirtybuffer2,1,vulgus_bgvideoram_size);
/* the background area is twice as tall and twice as large as the screen */
if ((tmpbitmap2 = osd_create_bitmap(2*Machine->drv->screen_width,2*Machine->drv->screen_height)) == 0)
{
free(dirtybuffer2);
generic_vh_stop();
return 1;
}
return 0;
}
/***************************************************************************
Stop the video hardware emulation.
***************************************************************************/
void vulgus_vh_stop(void)
{
osd_free_bitmap(tmpbitmap2);
free(dirtybuffer2);
generic_vh_stop();
}
WRITE_HANDLER( vulgus_bgvideoram_w )
{
if (vulgus_bgvideoram[offset] != data)
{
dirtybuffer2[offset] = 1;
vulgus_bgvideoram[offset] = data;
}
}
WRITE_HANDLER( vulgus_bgcolorram_w )
{
if (vulgus_bgcolorram[offset] != data)
{
dirtybuffer2[offset] = 1;
vulgus_bgcolorram[offset] = data;
}
}
WRITE_HANDLER( vulgus_palette_bank_w )
{
if (*vulgus_palette_bank != data)
{
memset(dirtybuffer2,1,vulgus_bgvideoram_size);
*vulgus_palette_bank = 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 vulgus_vh_screenrefresh(struct osd_bitmap *bitmap,int full_refresh)
{
int offs;
int scrollx,scrolly;
scrolly = -(vulgus_scrolllow[0] + 256 * vulgus_scrollhigh[0]);
scrollx = -(vulgus_scrolllow[1] + 256 * vulgus_scrollhigh[1]);
for (offs = vulgus_bgvideoram_size - 1;offs >= 0;offs--)
{
int sx,sy;
if (dirtybuffer2[offs])
{
// int minx,maxx,miny,maxy;
sx = (offs % 32);
sy = (offs / 32);
/* between level Vulgus changes the palette bank every frame. Redrawing */
/* the whole background every time would slow the game to a crawl, so here */
/* we check and redraw only the visible tiles */
/*
minx = (sx + scrollx) & 0x1ff;
maxx = (sx + 15 + scrollx) & 0x1ff;
if (minx > maxx) minx = maxx - 15;
miny = (sy + scrolly) & 0x1ff;
maxy = (sy + 15 + scrolly) & 0x1ff;
if (miny > maxy) miny = maxy - 15;
if (minx + 15 >= Machine->drv->visible_area.min_x &&
maxx - 15 <= Machine->drv->visible_area.max_x &&
miny + 15 >= Machine->drv->visible_area.min_y &&
maxy - 15 <= Machine->drv->visible_area.max_y)
*/
{
dirtybuffer2[offs] = 0;
drawgfx(tmpbitmap2,Machine->gfx[1],
vulgus_bgvideoram[offs] + 2 * (vulgus_bgcolorram[offs] & 0x80),
(vulgus_bgcolorram[offs] & 0x1f) + 32 * *vulgus_palette_bank,
vulgus_bgcolorram[offs] & 0x20,vulgus_bgcolorram[offs] & 0x40,
16*sy,16*sx,
0,TRANSPARENCY_NONE,0);
}
}
}
/* copy the background graphics */
copyscrollbitmap(bitmap,tmpbitmap2,1,&scrollx,1,&scrolly,&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
/* Draw the sprites. */
for (offs = spriteram_size - 4;offs >= 0;offs -= 4)
{
int code,i,col,sx,sy;
code = spriteram[offs];
col = spriteram[offs + 1] & 0x0f;
sx = spriteram[offs + 3];
sy = spriteram[offs + 2];
i = (spriteram[offs + 1] & 0xc0) >> 6;
if (i == 2) i = 3;
do
{
drawgfx(bitmap,Machine->gfx[2],
code + i,
col,
0, 0,
sx, sy + 16 * i,
&Machine->drv->visible_area,TRANSPARENCY_PEN,15);
/* draw again with wraparound */
drawgfx(bitmap,Machine->gfx[2],
code + i,
col,
0, 0,
sx, sy + 16 * i - 256,
&Machine->drv->visible_area,TRANSPARENCY_PEN,15);
i--;
} while (i >= 0);
}
/* draw the frontmost playfield. They are characters, but draw them as sprites */
for (offs = videoram_size - 1;offs >= 0;offs--)
{
int sx,sy;
sx = 8 * (offs % 32);
sy = 8 * (offs / 32);
drawgfx(bitmap,Machine->gfx[0],
videoram[offs] + 2 * (colorram[offs] & 0x80),
colorram[offs] & 0x3f,
0,0,
sx,sy,
&Machine->drv->visible_area,TRANSPARENCY_COLOR,47);
}
}