// license:BSD-3-Clause
// copyright-holders:Jarek Parchanski
/***************************************************************************
video.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "emu.h"
#include "includes/pingpong.h"
/***************************************************************************
Convert the color PROMs into a more useable format.
Ping Pong has a 32 bytes palette PROM and two 256 bytes color lookup table
PROMs (one for sprites, one for characters).
I don't know for sure how the palette PROM is connected to the RGB output,
but it's probably the usual:
bit 7 -- 220 ohm resistor -- BLUE
-- 470 ohm resistor -- BLUE
-- 220 ohm resistor -- GREEN
-- 470 ohm resistor -- GREEN
-- 1 kohm resistor -- GREEN
-- 220 ohm resistor -- RED
-- 470 ohm resistor -- RED
bit 0 -- 1 kohm resistor -- RED
***************************************************************************/
PALETTE_INIT_MEMBER(pingpong_state, pingpong)
{
const uint8_t *color_prom = memregion("proms")->base();
int i;
/* create a lookup table for the palette */
for (i = 0; i < 0x20; 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;
palette.set_indirect_color(i, rgb_t(r, g, b));
}
/* color_prom now points to the beginning of the lookup table */
color_prom += 0x20;
/* characters */
for (i = 0; i < 0x100; i++)
{
uint8_t ctabentry = (color_prom[i] & 0x0f) | 0x10;
palette.set_pen_indirect(i, ctabentry);
}
/* sprites */
for (i = 0x100; i < 0x200; i++)
{
uint8_t ctabentry = bitswap<8>(color_prom[i],7,6,5,4,0,1,2,3);
palette.set_pen_indirect(i, ctabentry);
}
}
WRITE8_MEMBER(pingpong_state::pingpong_videoram_w)
{
m_videoram[offset] = data;
m_bg_tilemap->mark_tile_dirty(offset);
}
WRITE8_MEMBER(pingpong_state::pingpong_colorram_w)
{
m_colorram[offset] = data;
m_bg_tilemap->mark_tile_dirty(offset);
}
TILE_GET_INFO_MEMBER(pingpong_state::get_bg_tile_info)
{
int attr = m_colorram[tile_index];
int code = m_videoram[tile_index] + ((attr & 0x20) << 3);
int color = attr & 0x1f;
int flags = ((attr & 0x40) ? TILE_FLIPX : 0) | ((attr & 0x80) ? TILE_FLIPY : 0);
SET_TILE_INFO_MEMBER(0, code, color, flags);
}
void pingpong_state::video_start()
{
m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(FUNC(pingpong_state::get_bg_tile_info),this), TILEMAP_SCAN_ROWS, 8, 8, 32, 32);
}
void pingpong_state::draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect )
{
/* This is strange; it's unlikely that the sprites actually have a hardware */
/* clipping region, but I haven't found another way to have them masked by */
/* the characters at the top and bottom of the screen. */
const rectangle spritevisiblearea(0*8, 32*8-1, 4*8, 29*8-1);
uint8_t *spriteram = m_spriteram;
int offs;
for (offs = m_spriteram.bytes() - 4;offs >= 0;offs -= 4)
{
int sx,sy,flipx,flipy,color,schar;
sx = spriteram[offs + 3];
sy = 241 - spriteram[offs + 1];
flipx = spriteram[offs] & 0x40;
flipy = spriteram[offs] & 0x80;
color = spriteram[offs] & 0x1f;
schar = spriteram[offs + 2] & 0x7f;
m_gfxdecode->gfx(1)->transmask(bitmap,spritevisiblearea,
schar,
color,
flipx,flipy,
sx,sy,
m_palette->transpen_mask(*m_gfxdecode->gfx(1), color, 0));
}
}
uint32_t pingpong_state::screen_update_pingpong(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
draw_sprites(bitmap, cliprect);
return 0;
}