/***************************************************************************
Lemmings video emulation - Bryan McPhail, mish@tendril.co.uk
*********************************************************************
There are two sets of sprites, the combination of custom chips 52 & 71.
There is a background pixel layer implemented with discrete logic
rather than a custom chip and a foreground VRAM tilemap layer that the
game mostly uses as a pixel layer (the vram format is arranged as
sequential pixels, rather than sequential characters).
***************************************************************************/
#include "emu.h"
#include "includes/lemmings.h"
static void draw_sprites( running_machine &machine, bitmap_t *bitmap, const rectangle *cliprect, UINT16 *spritedata, int gfxbank, UINT16 pri )
{
int offs;
for (offs = 0; offs < 0x400; offs += 4)
{
int x, y, sprite, colour, multi, fx, fy, inc, flash, mult;
sprite = spritedata[offs + 1] & 0x3fff;
if ((spritedata[offs + 2] & 0x2000) != pri)
continue;
y = spritedata[offs];
flash = y & 0x1000;
if (flash && (machine.primary_screen->frame_number() & 1))
continue;
x = spritedata[offs + 2];
colour = (x >>9) & 0xf;
fx = y & 0x2000;
fy = y & 0x4000;
multi = (1 << ((y & 0x0600) >> 9)) - 1; /* 1x, 2x, 4x, 8x height */
x = x & 0x01ff;
y = y & 0x01ff;
if (x >= 320) x -= 512;
if (y >= 256) y -= 512;
if (x > 320 || x < -16) continue;
sprite &= ~multi;
if (fy)
inc = 1;
else
{
sprite += multi;
inc = -1;
}
mult = -16;
while (multi >= 0)
{
drawgfx_transpen(bitmap,cliprect,machine.gfx[gfxbank],
sprite - multi * inc,
colour,
fx,fy,
x,y + mult * multi,0);
multi--;
}
}
}
/******************************************************************************/
static TILE_GET_INFO( get_tile_info )
{
lemmings_state *state = machine.driver_data<lemmings_state>();
UINT16 tile = state->m_vram_data[tile_index];
SET_TILE_INFO(
2,
tile&0x7ff,
(tile>>12)&0xf,
0);
}
VIDEO_START( lemmings )
{
lemmings_state *state = machine.driver_data<lemmings_state>();
state->m_bitmap0 = auto_bitmap_alloc(machine, 2048, 256, machine.primary_screen->format());
state->m_vram_tilemap = tilemap_create(machine, get_tile_info, tilemap_scan_cols, 8, 8, 64, 32);
state->m_vram_buffer = auto_alloc_array(machine, UINT8, 2048 * 64); /* 64 bytes per VRAM character */
state->m_sprite_triple_buffer_0 = auto_alloc_array(machine, UINT16, 0x800 / 2);
state->m_sprite_triple_buffer_1 = auto_alloc_array(machine, UINT16, 0x800 / 2);
tilemap_set_transparent_pen(state->m_vram_tilemap, 0);
bitmap_fill(state->m_bitmap0, 0, 0x100);
gfx_element_set_source(machine.gfx[2], state->m_vram_buffer);
state->save_item(NAME(*state->m_bitmap0));
state->save_pointer(NAME(state->m_vram_buffer), 2048 * 64);
state->save_pointer(NAME(state->m_sprite_triple_buffer_0), 0x800 / 2);
state->save_pointer(NAME(state->m_sprite_triple_buffer_1), 0x800 / 2);
}
SCREEN_EOF( lemmings )
{
lemmings_state *state = machine.driver_data<lemmings_state>();
memcpy(state->m_sprite_triple_buffer_0, machine.generic.buffered_spriteram.u16, 0x800);
memcpy(state->m_sprite_triple_buffer_1, machine.generic.buffered_spriteram2.u16, 0x800);
}
/******************************************************************************/
WRITE16_HANDLER( lemmings_pixel_0_w )
{
lemmings_state *state = space->machine().driver_data<lemmings_state>();
int sx, sy, src, old;
old = state->m_pixel_0_data[offset];
COMBINE_DATA(&state->m_pixel_0_data[offset]);
src = state->m_pixel_0_data[offset];
if (old == src)
return;
sy = (offset << 1) / 0x800;
sx = (offset << 1) & 0x7ff;
if (sx > 2047 || sy > 255)
return;
*BITMAP_ADDR16(state->m_bitmap0, sy, sx + 0) = ((src >> 8) & 0xf) | 0x100;
*BITMAP_ADDR16(state->m_bitmap0, sy, sx + 1) = ((src >> 0) & 0xf) | 0x100;
}
WRITE16_HANDLER( lemmings_pixel_1_w )
{
lemmings_state *state = space->machine().driver_data<lemmings_state>();
int sx, sy, src, /*old,*/ tile;
// old = state->m_pixel_1_data[offset];
COMBINE_DATA(&state->m_pixel_1_data[offset]);
src = state->m_pixel_1_data[offset];
// if (old == src)
// return;
sy = ((offset << 1) / 0x200);
sx = ((offset << 1) & 0x1ff);
/* Copy pixel to buffer for easier decoding later */
tile = ((sx / 8) * 32) + (sy / 8);
gfx_element_mark_dirty(space->machine().gfx[2], tile);
state->m_vram_buffer[(tile * 64) + ((sx & 7)) + ((sy & 7) * 8)] = (src >> 8) & 0xf;
sx += 1; /* Update both pixels in the word */
state->m_vram_buffer[(tile * 64) + ((sx & 7)) + ((sy & 7) * 8)] = (src >> 0) & 0xf;
}
WRITE16_HANDLER( lemmings_vram_w )
{
lemmings_state *state = space->machine().driver_data<lemmings_state>();
COMBINE_DATA(&state->m_vram_data[offset]);
tilemap_mark_tile_dirty(state->m_vram_tilemap, offset);
}
SCREEN_UPDATE( lemmings )
{
lemmings_state *state = screen->machine().driver_data<lemmings_state>();
int x1 = -state->m_control_data[0];
int x0 = -state->m_control_data[2];
int y = 0;
rectangle rect;
rect.max_y = cliprect->max_y;
rect.min_y = cliprect->min_y;
bitmap_fill(bitmap, cliprect, get_black_pen(screen->machine()));
draw_sprites(screen->machine(), bitmap, cliprect, state->m_sprite_triple_buffer_1, 1, 0x0000);
/* Pixel layer can be windowed in hardware (two player mode) */
if ((state->m_control_data[6] & 2) == 0)
copyscrollbitmap_trans(bitmap, state->m_bitmap0, 1, &x1, 1, &y, cliprect, 0x100);
else
{
rect.max_x = 159;
rect.min_x = 0;
copyscrollbitmap_trans(bitmap, state->m_bitmap0, 1, &x0, 1, &y, &rect, 0x100);
rect.max_x = 319;
rect.min_x = 160;
copyscrollbitmap_trans(bitmap, state->m_bitmap0, 1, &x1, 1, &y, &rect, 0x100);
}
draw_sprites(screen->machine(), bitmap, cliprect, state->m_sprite_triple_buffer_0, 0, 0x0000);
draw_sprites(screen->machine(), bitmap, cliprect, state->m_sprite_triple_buffer_1, 1, 0x2000);
tilemap_draw(bitmap, cliprect, state->m_vram_tilemap, 0, 0);
draw_sprites(screen->machine(), bitmap, cliprect, state->m_sprite_triple_buffer_0, 0, 0x2000);
return 0;
}