// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/***************************************************************************
Sega System 16B hardware
***************************************************************************/
#include "emu.h"
#include "includes/segas16b.h"
//-------------------------------------------------
// video_start - initialize the video system
//-------------------------------------------------
void segas16b_state::video_start()
{
// initialize the tile/text layers
m_segaic16vid->tilemap_init( 0, m_tilemap_type, 0x000, 0, 2);
}
//-------------------------------------------------
// screen_update - render all graphics
//-------------------------------------------------
uint32_t segas16b_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
if (m_sprites.found())
m_sprites->draw_async(cliprect);
// reset priorities
screen.priority().fill(0, cliprect);
// draw background opaquely first, not setting any priorities
m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_BACKGROUND, 0 | TILEMAP_DRAW_OPAQUE, 0x00);
m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_BACKGROUND, 1 | TILEMAP_DRAW_OPAQUE, 0x00);
// draw background again, just to set the priorities on non-transparent pixels
bitmap_ind16 dummy_bitmap;
m_segaic16vid->tilemap_draw( screen, dummy_bitmap, cliprect, 0, segaic16_video_device::TILEMAP_BACKGROUND, 0, 0x01);
m_segaic16vid->tilemap_draw( screen, dummy_bitmap, cliprect, 0, segaic16_video_device::TILEMAP_BACKGROUND, 1, 0x02);
// draw foreground
m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_FOREGROUND, 0, 0x02);
m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_FOREGROUND, 1, 0x04);
// text layer
m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_TEXT, 0, 0x04);
m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_TEXT, 1, 0x08);
// mix in sprites
if (!m_sprites.found()) return 0;
bitmap_ind16 &sprites = m_sprites->bitmap();
for (const sparse_dirty_rect *rect = m_sprites->first_dirty_rect(cliprect); rect != nullptr; rect = rect->next())
for (int y = rect->min_y; y <= rect->max_y; y++)
{
uint16_t *dest = &bitmap.pix(y);
uint16_t *src = &sprites.pix(y);
uint8_t *pri = &screen.priority().pix(y);
for (int x = rect->min_x; x <= rect->max_x; x++)
{
// only process written pixels
uint16_t pix = src[x];
if (pix != 0xffff)
{
// compare sprite priority against tilemap priority
int priority = (pix >> 10) & 3;
if ((1 << priority) > pri[x])
{
// if the color is set to maximum, shadow pixels underneath us
if ((pix & 0x03f0) == 0x03f0)
dest[x] += (m_paletteram[dest[x]] & 0x8000) ? m_palette_entries*2 : m_palette_entries;
// otherwise, just add in sprite palette base
else
dest[x] = m_spritepalbase | (pix & 0x3ff);
}
}
}
}
return 0;
}