/*****************************************************************************************
Speed Attack video hardware emulation
*****************************************************************************************/
#include "emu.h"
#include "includes/speedatk.h"
#include "video/mc6845.h"
PALETTE_INIT( speedatk )
{
int i;
/* allocate the colortable */
machine.colortable = colortable_alloc(machine, 0x10);
/* create a lookup table for the palette */
for (i = 0; i < 0x10; i++)
{
int bit0, bit1, bit2;
int r, g, b;
/* red component */
bit0 = (color_prom[i] >> 0) & 0x01;
bit1 = (color_prom[i] >> 1) & 0x01;
bit2 = (color_prom[i] >> 2) & 0x01;
r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = (color_prom[i] >> 3) & 0x01;
bit1 = (color_prom[i] >> 4) & 0x01;
bit2 = (color_prom[i] >> 5) & 0x01;
g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = 0;
bit1 = (color_prom[i] >> 6) & 0x01;
bit2 = (color_prom[i] >> 7) & 0x01;
b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
colortable_palette_set_color(machine.colortable, i, MAKE_RGB(r, g, b));
}
/* color_prom now points to the beginning of the lookup table */
color_prom += 0x20;
for (i = 0; i < 0x100; i++)
{
UINT8 ctabentry = color_prom[i] & 0x0f;
colortable_entry_set_value(machine.colortable, i, ctabentry);
}
}
WRITE8_HANDLER( speedatk_videoram_w )
{
speedatk_state *state = space->machine().driver_data<speedatk_state>();
state->m_videoram[offset] = data;
}
WRITE8_HANDLER( speedatk_colorram_w )
{
speedatk_state *state = space->machine().driver_data<speedatk_state>();
state->m_colorram[offset] = data;
}
VIDEO_START( speedatk )
{
}
WRITE8_HANDLER( speedatk_6845_w )
{
speedatk_state *state = space->machine().driver_data<speedatk_state>();
if(offset == 0)
{
state->m_crtc_index = data;
space->machine().device<mc6845_device>("crtc")->address_w(*space,0,data);
}
else
{
state->m_crtc_vreg[state->m_crtc_index] = data;
space->machine().device<mc6845_device>("crtc")->register_w(*space,0,data);
}
}
SCREEN_UPDATE( speedatk )
{
speedatk_state *state = screen->machine().driver_data<speedatk_state>();
int x,y;
int count;
UINT16 tile;
UINT8 color, region;
bitmap_fill(bitmap, cliprect, 0);
count = (state->m_crtc_vreg[0x0c]<<8)|(state->m_crtc_vreg[0x0d] & 0xff);
if(state->m_flip_scr) { count = 0x3ff - count; }
for(y=0;y<state->m_crtc_vreg[6];y++)
{
for(x=0;x<state->m_crtc_vreg[1];x++)
{
tile = state->m_videoram[count] + ((state->m_colorram[count] & 0xe0) << 3);
color = state->m_colorram[count] & 0x1f;
region = (state->m_colorram[count] & 0x10) >> 4;
drawgfx_opaque(bitmap,cliprect,screen->machine().gfx[region],tile,color,state->m_flip_scr,state->m_flip_scr,x*8,y*8);
count = (state->m_flip_scr) ? count-1 : count+1;
count&=0x3ff;
}
}
return 0;
}