UINT32 segaybd_state::screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
// if no drawing is happening, fill with black and get out
if (!m_segaic16vid->segaic16_display_enable)
{
bitmap.fill(m_palette->black_pen(), cliprect);
return 0;
}
// start the sprites drawing
rectangle yboard_clip(0, 511, 0, 511);
m_ysprites->bitmap().fill(0xffff);
m_ysprites->draw_async(yboard_clip);
m_bsprites->draw_async(cliprect);
// apply rotation
m_segaic16vid->segaic16_rotate_draw(0, bitmap, cliprect, screen.priority(), m_ysprites->bitmap());
// mix in 16B sprites
bitmap_ind16 &sprites = m_bsprites->bitmap();
for (const sparse_dirty_rect *rect = m_bsprites->first_dirty_rect(cliprect); rect != NULL; rect = rect->next())
for (int y = rect->min_y; y <= rect->max_y; y++)
{
UINT16 *dest = &bitmap.pix(y);
UINT16 *src = &sprites.pix(y);
UINT8 *pri = &screen.priority().pix(y);
for (int x = rect->min_x; x <= rect->max_x; x++)
{
// only process written pixels
UINT16 pix = src[x];
if (pix != 0xffff)
{
// compare sprite priority against tilemap priority
int priority = (pix >> 11) & 0x1e;
if (priority < pri[x])
{
// if the color is set to maximum, shadow pixels underneath us
if ((pix & 0xf) == 0xe)
dest[x] += (m_paletteram[dest[x]] & 0x8000) ? m_palette_entries*2 : m_palette_entries;
// otherwise, just add in sprite palette base
else
dest[x] = 0x800 | (pix & 0x7ff);
}
}
}
}
UINT32 segaybd_state::screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
// if no drawing is happening, fill with black and get out
if (!m_segaic16vid->m_display_enable)
{
bitmap.fill(m_palette->black_pen(), cliprect);
return 0;
}
// start the sprites drawing
rectangle yboard_clip(0, 511, 0, 511);
m_ysprites->bitmap().fill(0xffff);
m_ysprites->draw_async(yboard_clip);
m_bsprites->draw_async(cliprect);
// apply rotation
m_segaic16vid->rotate_draw(0, bitmap, cliprect, screen.priority(), m_ysprites->bitmap());
// mix in 16B sprites
bitmap_ind16 &sprites = m_bsprites->bitmap();
for (const sparse_dirty_rect *rect = m_bsprites->first_dirty_rect(cliprect); rect != nullptr; rect = rect->next())
for (int y = rect->min_y; y <= rect->max_y; y++)
{
UINT16 *dest = &bitmap.pix(y);
UINT16 *src = &sprites.pix(y);
UINT8 *pri = &screen.priority().pix(y);
for (int x = rect->min_x; x <= rect->max_x; x++)
{
// only process written pixels
UINT16 pix = src[x];
if (pix != 0xffff)
{
// the 16b priority bits are stored like this
// int colpri = ((data[4] & 0xff) << 4) | (((data[1] >> 9) & 0xf) << 12);
// so PPPPppppppppcccc (P = priority p = palette c = colour data)
// for Y board the (((data[1] >> 9) & 0xf) << 12) bit is the part we care about
// the format of the screen.priority() buffer (populated in rotate_draw) is
// ccc----- Sprite color
// ---rrrr- Sprite priority
// -------1 'was Indirected color data' before rotate_draw, forced to 1 when filling pri buffer
// compare sprite priority against tilemap priority
int priority = (pix >> 11) & 0x1e;
if (priority < (pri[x] & 0x1f))
{
// if the color is set to maximum, shadow pixels underneath us
if ((pix & 0xf) == 0xe)
dest[x] += (m_paletteram[dest[x]] & 0x8000) ? m_palette_entries*2 : m_palette_entries;
// otherwise, just add in sprite palette base
else
dest[x] = 0x800 | (pix & 0x7ff);
}
}
}
}
