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AmigActive 10
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vidhrdw
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gundealr.c
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C/C++ Source or Header
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2000-04-04
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4KB
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158 lines
/***************************************************************************
vidhrdw.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
unsigned char *gundealr_bg_videoram,*gundealr_fg_videoram;
static struct tilemap *bg_tilemap,*fg_tilemap;
static int flipscreen;
/***************************************************************************
Callbacks for the TileMap code
***************************************************************************/
static void get_bg_tile_info(int tile_index)
{
unsigned char attr = gundealr_bg_videoram[2*tile_index+1];
SET_TILE_INFO(0,gundealr_bg_videoram[2*tile_index] + ((attr & 0x07) << 8),(attr & 0xf0) >> 4)
}
static UINT32 gundealr_scan(UINT32 col,UINT32 row,UINT32 num_cols,UINT32 num_rows)
{
/* logical (col,row) -> memory offset */
return (row & 0x0f) + ((col & 0x3f) << 4) + ((row & 0x10) << 6);
}
static void get_fg_tile_info(int tile_index)
{
unsigned char attr = gundealr_fg_videoram[2*tile_index+1];
SET_TILE_INFO(1,gundealr_fg_videoram[2*tile_index] + ((attr & 0x03) << 8),(attr & 0xf0) >> 4)
}
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
int gundealr_vh_start(void)
{
bg_tilemap = tilemap_create(get_bg_tile_info,tilemap_scan_cols,TILEMAP_OPAQUE, 8, 8,32,32);
fg_tilemap = tilemap_create(get_fg_tile_info,gundealr_scan, TILEMAP_TRANSPARENT,16,16,64,32);
if (!bg_tilemap || !fg_tilemap)
return 1;
fg_tilemap->transparent_pen = 15;
return 0;
}
/***************************************************************************
Memory handlers
***************************************************************************/
WRITE_HANDLER( gundealr_bg_videoram_w )
{
if (gundealr_bg_videoram[offset] != data)
{
gundealr_bg_videoram[offset] = data;
tilemap_mark_tile_dirty(bg_tilemap,offset/2);
}
}
WRITE_HANDLER( gundealr_fg_videoram_w )
{
if (gundealr_fg_videoram[offset] != data)
{
gundealr_fg_videoram[offset] = data;
tilemap_mark_tile_dirty(fg_tilemap,offset/2);
}
}
WRITE_HANDLER( gundealr_paletteram_w )
{
int r,g,b,val;
paletteram[offset] = data;
val = paletteram[offset & ~1];
r = (val >> 4) & 0x0f;
g = (val >> 0) & 0x0f;
val = paletteram[offset | 1];
b = (val >> 4) & 0x0f;
/* TODO: the bottom 4 bits are used as well, but I'm not sure about the meaning */
r = 0x11 * r;
g = 0x11 * g;
b = 0x11 * b;
palette_change_color(offset / 2,r,g,b);
}
WRITE_HANDLER( gundealr_fg_scroll_w )
{
static unsigned char scroll[4];
scroll[offset] = data;
tilemap_set_scrollx(fg_tilemap,0,scroll[1] | ((scroll[0] & 0x03) << 8));
tilemap_set_scrolly(fg_tilemap,0,scroll[3] | ((scroll[2] & 0x03) << 8));
}
WRITE_HANDLER( yamyam_fg_scroll_w )
{
static unsigned char scroll[4];
scroll[offset] = data;
tilemap_set_scrollx(fg_tilemap,0,scroll[0] | ((scroll[1] & 0x03) << 8));
tilemap_set_scrolly(fg_tilemap,0,scroll[2] | ((scroll[3] & 0x03) << 8));
}
WRITE_HANDLER( gundealr_flipscreen_w )
{
flipscreen = data;
tilemap_set_flip(ALL_TILEMAPS,flipscreen ? (TILEMAP_FLIPY | TILEMAP_FLIPX) : 0);
}
/***************************************************************************
Display refresh
***************************************************************************/
void gundealr_vh_screenrefresh(struct osd_bitmap *bitmap,int full_refresh)
{
tilemap_update(ALL_TILEMAPS);
palette_init_used_colors();
if (palette_recalc())
tilemap_mark_all_pixels_dirty(ALL_TILEMAPS);
tilemap_render(ALL_TILEMAPS);
tilemap_draw(bitmap,bg_tilemap,0);
tilemap_draw(bitmap,fg_tilemap,0);
}