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// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/***************************************************************************
Atari G42 hardware
*****************************************************************************
MO data has 12 bits total: MVID0-11
MVID9-11 form the priority
MVID0-9 form the color bits
PF data has 13 bits total: PF.VID0-12
PF.VID10-12 form the priority
PF.VID0-9 form the color bits
Upper bits come from the low 5 bits of the HSCROLL value in alpha RAM
Playfield bank comes from low 2 bits of the VSCROLL value in alpha RAM
For GX2, there are 4 bits of bank
****************************************************************************/
#include "emu.h"
#include "atarirle.h"
#include "atarig42.h"
/*************************************
*
* Tilemap callbacks
*
*************************************/
TILE_GET_INFO_MEMBER(atarig42_state::get_alpha_tile_info)
{
uint16_t data = m_alpha_tilemap->basemem_read(tile_index);
int code = data & 0xfff;
int color = (data >> 12) & 0x0f;
int opaque = data & 0x8000;
tileinfo.set(1, code, color, opaque ? TILE_FORCE_LAYER0 : 0);
}
TILE_GET_INFO_MEMBER(atarig42_state::get_playfield_tile_info)
{
uint16_t data = m_playfield_tilemap->basemem_read(tile_index);
int code = (m_playfield_tile_bank << 12) | (data & 0xfff);
int color = (m_playfield_base >> 5) + ((m_playfield_color_bank << 3) & 0x18) + ((data >> 12) & 7);
tileinfo.set(0, code, color, (data >> 15) & 1);
tileinfo.category = (m_playfield_color_bank >> 2) & 7;
}
TILEMAP_MAPPER_MEMBER(atarig42_state::atarig42_playfield_scan)
{
int bank = 1 - (col / (num_cols / 2));
return bank * (num_rows * num_cols / 2) + row * (num_cols / 2) + (col % (num_cols / 2));
}
/*************************************
*
* Video system start
*
*************************************/
void atarig42_state::video_start()
{
/* blend the playfields and free the temporary one */
blend_gfx(0, 2, 0x0f, 0x30);
/* save states */
save_item(NAME(m_current_control));
save_item(NAME(m_playfield_tile_bank));
save_item(NAME(m_playfield_color_bank));
save_item(NAME(m_playfield_xscroll));
save_item(NAME(m_playfield_yscroll));
}
/*************************************
*
* Periodic scanline updater
*
*************************************/
TIMER_DEVICE_CALLBACK_MEMBER(atarig42_state::scanline_update)
{
int scanline = param;
/* keep in range */
int offset = (scanline / 8) * 64 + 48;
if (offset >= 0x800)
return;
/* update the playfield scrolls */
for (int i = 0; i < 8; i++)
{
uint16_t word;
word = m_alpha_tilemap->basemem_read(offset++);
if (word & 0x8000)
{
int newscroll = (word >> 5) & 0x3ff;
int newbank = word & 0x1f;
if (newscroll != m_playfield_xscroll)
{
if (scanline + i > 0)
m_screen->update_partial(scanline + i - 1);
m_playfield_tilemap->set_scrollx(0, newscroll);
m_playfield_xscroll = newscroll;
}
if (newbank != m_playfield_color_bank)
{
if (scanline + i > 0)
m_screen->update_partial(scanline + i - 1);
m_playfield_tilemap->mark_all_dirty();
m_playfield_color_bank = newbank;
}
}
word = m_alpha_tilemap->basemem_read(offset++);
if (word & 0x8000)
{
int newscroll = ((word >> 6) - (scanline + i)) & 0x1ff;
int newbank = word & 7;
if (newscroll != m_playfield_yscroll)
{
if (scanline + i > 0)
m_screen->update_partial(scanline + i - 1);
m_playfield_tilemap->set_scrolly(0, newscroll);
m_playfield_yscroll = newscroll;
}
if (newbank != m_playfield_tile_bank)
{
if (scanline + i > 0)
m_screen->update_partial(scanline + i - 1);
m_playfield_tilemap->mark_all_dirty();
m_playfield_tile_bank = newbank;
}
}
}
}
/*************************************
*
* Main refresh
*
*************************************/
uint32_t atarig42_state::screen_update_atarig42(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
bitmap_ind8 &priority_bitmap = screen.priority();
/* draw the playfield */
priority_bitmap.fill(0, cliprect);
m_playfield_tilemap->draw(screen, bitmap, cliprect, 0, 0);
m_playfield_tilemap->draw(screen, bitmap, cliprect, 1, 1);
m_playfield_tilemap->draw(screen, bitmap, cliprect, 2, 2);
m_playfield_tilemap->draw(screen, bitmap, cliprect, 3, 3);
m_playfield_tilemap->draw(screen, bitmap, cliprect, 4, 4);
m_playfield_tilemap->draw(screen, bitmap, cliprect, 5, 5);
m_playfield_tilemap->draw(screen, bitmap, cliprect, 6, 6);
m_playfield_tilemap->draw(screen, bitmap, cliprect, 7, 7);
/* copy the motion objects on top */
{
bitmap_ind16 &mo_bitmap = m_rle->vram(0);
int const left = cliprect.left();
int const top = cliprect.top();
int const right = cliprect.right() + 1;
int const bottom = cliprect.bottom() + 1;
/* now blend with the playfield */
for (int y = top; y < bottom; y++)
{
uint16_t *const pf = &bitmap.pix(y);
uint16_t const *const mo = &mo_bitmap.pix(y);
uint8_t const *const pri = &priority_bitmap.pix(y);
for (int x = left; x < right; x++)
if (mo[x])
{
int const pfpri = pri[x];
int const mopri = mo[x] >> ATARIRLE_PRIORITY_SHIFT;
if (mopri >= pfpri)
pf[x] = mo[x] & ATARIRLE_DATA_MASK;
}
}
}
/* add the alpha on top */
m_alpha_tilemap->draw(screen, bitmap, cliprect, 0, 0);
return 0;
}
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