// license:BSD-3-Clause
// copyright-holders:Zsolt Vasvari
/***************************************************************************
video.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "emu.h"
#include "video/resnet.h"
#include "includes/sbasketb.h"
/***************************************************************************
Convert the color PROMs into a more useable format.
Super Basketball has three 256x4 palette PROMs (one per gun) and two 256x4
lookup table PROMs (one for characters, one for sprites).
I don't know for sure how the palette PROMs are connected to the RGB
output, but it's probably the usual:
bit 3 -- 220 ohm resistor -- RED/GREEN/BLUE
-- 470 ohm resistor -- RED/GREEN/BLUE
-- 1 kohm resistor -- RED/GREEN/BLUE
bit 0 -- 2.2kohm resistor -- RED/GREEN/BLUE
***************************************************************************/
void sbasketb_state::sbasketb_palette(palette_device &palette) const
{
const uint8_t *color_prom = memregion("proms")->base();
static constexpr int resistances[4] = { 2000, 1000, 470, 220 };
// compute the color output resistor weights
double rweights[4], gweights[4], bweights[4];
compute_resistor_weights(0, 255, -1.0,
4, resistances, rweights, 1000, 0,
4, resistances, gweights, 1000, 0,
4, resistances, bweights, 1000, 0);
// create a lookup table for the palette
for (int i = 0; i < 0x100; i++)
{
int bit0, bit1, bit2, bit3;
// red component
bit0 = BIT(color_prom[i | 0x000], 0);
bit1 = BIT(color_prom[i | 0x000], 1);
bit2 = BIT(color_prom[i | 0x000], 2);
bit3 = BIT(color_prom[i | 0x000], 3);
int const r = combine_weights(rweights, bit0, bit1, bit2, bit3);
// green component
bit0 = BIT(color_prom[i | 0x100], 0);
bit1 = BIT(color_prom[i | 0x100], 1);
bit2 = BIT(color_prom[i | 0x100], 2);
bit3 = BIT(color_prom[i | 0x100], 3);
int const g = combine_weights(gweights, bit0, bit1, bit2, bit3);
// blue component
bit0 = BIT(color_prom[i | 0x200], 0);
bit1 = BIT(color_prom[i | 0x200], 1);
bit2 = BIT(color_prom[i | 0x200], 2);
bit3 = BIT(color_prom[i | 0x200], 3);
int const b = combine_weights(bweights, bit0, bit1, bit2, bit3);
palette.set_indirect_color(i, rgb_t(r, g, b));
}
// color_prom now points to the beginning of the lookup table
color_prom += 0x300;
// characters use colors 0xf0-0xff
for (int i = 0; i < 0x100; i++)
{
uint8_t const ctabentry = (color_prom[i] & 0x0f) | 0xf0;
palette.set_pen_indirect(i, ctabentry);
}
// sprites use colors 0-256 (?) in 16 banks
for (int i = 0; i < 0x100; i++)
{
for (int j = 0; j < 0x10; j++)
{
uint8_t const ctabentry = (j << 4) | (color_prom[i + 0x100] & 0x0f);
palette.set_pen_indirect(0x100 + ((j << 8) | i), ctabentry);
}
}
}
WRITE8_MEMBER(sbasketb_state::sbasketb_videoram_w)
{
m_videoram[offset] = data;
m_bg_tilemap->mark_tile_dirty(offset);
}
WRITE8_MEMBER(sbasketb_state::sbasketb_colorram_w)
{
m_colorram[offset] = data;
m_bg_tilemap->mark_tile_dirty(offset);
}
WRITE_LINE_MEMBER(sbasketb_state::flipscreen_w)
{
flip_screen_set(state);
machine().tilemap().mark_all_dirty();
}
WRITE_LINE_MEMBER(sbasketb_state::spriteram_select_w)
{
m_spriteram_select = state;
}
TILE_GET_INFO_MEMBER(sbasketb_state::get_bg_tile_info)
{
int code = m_videoram[tile_index] + ((m_colorram[tile_index] & 0x20) << 3);
int color = m_colorram[tile_index] & 0x0f;
int flags = ((m_colorram[tile_index] & 0x40) ? TILE_FLIPX : 0) | ((m_colorram[tile_index] & 0x80) ? TILE_FLIPY : 0);
SET_TILE_INFO_MEMBER(0, code, color, flags);
}
void sbasketb_state::video_start()
{
m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(sbasketb_state::get_bg_tile_info)), TILEMAP_SCAN_ROWS, 8, 8, 32, 32);
m_bg_tilemap->set_scroll_cols(32);
save_item(NAME(m_spriteram_select));
}
void sbasketb_state::draw_sprites( bitmap_ind16 &bitmap, const rectangle &cliprect )
{
uint8_t *spriteram = m_spriteram;
int offs = m_spriteram_select ? 0x100 : 0;
int i;
for (i = 0; i < 64; i++, offs += 4)
{
int sx = spriteram[offs + 2];
int sy = spriteram[offs + 3];
if (sx || sy)
{
int code = spriteram[offs + 0] | ((spriteram[offs + 1] & 0x20) << 3);
int color = (spriteram[offs + 1] & 0x0f) + 16 * *m_palettebank;
int flipx = spriteram[offs + 1] & 0x40;
int flipy = spriteram[offs + 1] & 0x80;
if (flip_screen())
{
sx = 240 - sx;
sy = 240 - sy;
flipx = !flipx;
flipy = !flipy;
}
m_gfxdecode->gfx(1)->transpen(bitmap,cliprect,
code, color,
flipx, flipy,
sx, sy, 0);
}
}
}
uint32_t sbasketb_state::screen_update_sbasketb(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
int col;
for (col = 6; col < 32; col++)
m_bg_tilemap->set_scrolly(col, *m_scroll);
m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
draw_sprites(bitmap, cliprect);
return 0;
}