// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/***************************************************************************
Atari Blasteroids hardware
****************************************************************************/
#include "emu.h"
#include "machine/atarigen.h"
#include "video/atarimo.h"
#include "includes/blstroid.h"
/*************************************
*
* Tilemap callbacks
*
*************************************/
TILE_GET_INFO_MEMBER(blstroid_state::get_playfield_tile_info)
{
uint16_t data = m_playfield_tilemap->basemem_read(tile_index);
int code = data & 0x1fff;
int color = (data >> 13) & 0x07;
SET_TILE_INFO_MEMBER(0, code, color, 0);
}
/*************************************
*
* Video system start
*
*************************************/
const atari_motion_objects_config blstroid_state::s_mob_config =
{
1, /* index to which gfx system */
1, /* number of motion object banks */
1, /* are the entries linked? */
0, /* are the entries split? */
0, /* render in reverse order? */
0, /* render in swapped X/Y order? */
0, /* does the neighbor bit affect the next object? */
0, /* pixels per SLIP entry (0 for no-slip) */
0, /* pixel offset for SLIPs */
0, /* maximum number of links to visit/scanline (0=all) */
0x000, /* base palette entry */
0x100, /* maximum number of colors */
0, /* transparent pen index */
{{ 0,0,0x0ff8,0 }}, /* mask for the link */
{{ 0,0x3fff,0,0 }}, /* mask for the code index */
{{ 0,0,0,0x000f }}, /* mask for the color */
{{ 0,0,0,0xffc0 }}, /* mask for the X position */
{{ 0xff80,0,0,0 }}, /* mask for the Y position */
{{ 0 }}, /* mask for the width, in tiles*/
{{ 0x000f,0,0,0 }}, /* mask for the height, in tiles */
{{ 0,0x8000,0,0 }}, /* mask for the horizontal flip */
{{ 0,0x4000,0,0 }}, /* mask for the vertical flip */
{{ 0 }}, /* mask for the priority */
{{ 0 }}, /* mask for the neighbor */
{{ 0 }}, /* mask for absolute coordinates */
{{ 0 }}, /* mask for the special value */
0 /* resulting value to indicate "special" */
};
VIDEO_START_MEMBER(blstroid_state,blstroid)
{
m_irq_off_timer = timer_alloc(TIMER_IRQ_OFF);
m_irq_on_timer = timer_alloc(TIMER_IRQ_ON);
}
/*************************************
*
* Periodic scanline updater
*
*************************************/
void blstroid_state::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
{
switch (id)
{
case TIMER_IRQ_OFF:
/* clear the interrupt */
scanline_int_ack_w();
break;
case TIMER_IRQ_ON:
/* generate the interrupt */
scanline_int_write_line(1);
update_interrupts();
break;
default:
atarigen_state::device_timer(timer, id, param, ptr);
break;
}
}
void blstroid_state::scanline_update(screen_device &screen, int scanline)
{
int offset = (scanline / 8) * 64 + 40;
/* check for interrupts */
if (offset < 0x1000)
if (m_playfield_tilemap->basemem_read(offset) & 0x8000)
{
/* FIXME: - the only thing this IRQ does it tweak the starting MO link */
/* unfortunately, it does it too early for the given MOs! */
/* perhaps it is not actually hooked up on the real PCB... */
return;
/* set a timer to turn the interrupt on at HBLANK of the 7th scanline */
/* and another to turn it off one scanline later */
int width = screen.width();
int vpos = screen.vpos();
attotime period_on = screen.time_until_pos(vpos + 7, width * 0.9);
attotime period_off = screen.time_until_pos(vpos + 8, width * 0.9);
m_irq_on_timer->adjust(period_on);
m_irq_off_timer->adjust(period_off);
}
}
/*************************************
*
* Main refresh
*
*************************************/
uint32_t blstroid_state::screen_update_blstroid(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
// start drawing
m_mob->draw_async(cliprect);
/* draw the playfield */
m_playfield_tilemap->draw(screen, bitmap, cliprect, 0, 0);
/* draw and merge the MO */
bitmap_ind16 &mobitmap = m_mob->bitmap();
for (const sparse_dirty_rect *rect = m_mob->first_dirty_rect(cliprect); rect != nullptr; rect = rect->next())
for (int y = rect->top(); y <= rect->bottom(); y++)
{
uint16_t *mo = &mobitmap.pix16(y);
uint16_t *pf = &bitmap.pix16(y);
for (int x = rect->left(); x <= rect->right(); x++)
if (mo[x] != 0xffff)
{
/* verified via schematics
priority address = HPPPMMMM
*/
int priaddr = ((pf[x] & 8) << 4) | (pf[x] & 0x70) | ((mo[x] & 0xf0) >> 4);
if (m_priorityram[priaddr] & 1)
pf[x] = mo[x];
}
}
return 0;
}