diff options
Diffstat (limited to 'src/mame/video/champbas.c')
-rw-r--r-- | src/mame/video/champbas.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/src/mame/video/champbas.c b/src/mame/video/champbas.c new file mode 100644 index 00000000000..62e865876b8 --- /dev/null +++ b/src/mame/video/champbas.c @@ -0,0 +1,151 @@ +/*************************************************************************** + + video.c + + Functions to emulate the video hardware of the machine. + +***************************************************************************/ + +#include "driver.h" + +static int gfxbank; + +static tilemap *bg_tilemap; + +/*************************************************************************** + + Convert the color PROMs into a more useable format. + + Pac Man has a 16 bytes palette PROM and a 128 bytes color lookup table PROM. + + Pengo has a 32 bytes palette PROM and a 256 bytes color lookup table PROM + (actually that's 512 bytes, but the high address bit is grounded). + + The palette PROM is connected to the RGB output this way: + + 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( champbas ) +{ + int i; + #define TOTAL_COLORS(gfxn) (machine->gfx[gfxn]->total_colors * machine->gfx[gfxn]->color_granularity) + #define COLOR(gfxn,offs) (colortable[machine->drv->gfxdecodeinfo[gfxn].color_codes_start + offs]) + + + for (i = 0;i < machine->drv->total_colors;i++) + { + int bit0,bit1,bit2,r,g,b; + + + /* red component */ + bit0 = (*color_prom >> 0) & 0x01; + bit1 = (*color_prom >> 1) & 0x01; + bit2 = (*color_prom >> 2) & 0x01; + r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2; + /* green component */ + bit0 = (*color_prom >> 3) & 0x01; + bit1 = (*color_prom >> 4) & 0x01; + bit2 = (*color_prom >> 5) & 0x01; + g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2; + /* blue component */ + bit0 = 0; + bit1 = (*color_prom >> 6) & 0x01; + bit2 = (*color_prom >> 7) & 0x01; + b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2; + + palette_set_color(machine,i,MAKE_RGB(r,g,b)); + color_prom++; + } + + /* color_prom now points to the beginning of the lookup table */ + + /* TODO: there are 32 colors in the palette, but we are suing only 16 */ + /* the only difference between the two banks is color #14, grey instead of green */ + + /* character lookup table */ + /* sprites use the same color lookup table as characters */ + for (i = 0;i < TOTAL_COLORS(0);i++) + COLOR(0,i) = (*(color_prom++) & 0x0f); +} + +WRITE8_HANDLER( champbas_videoram_w ) +{ + videoram[offset] = data; + tilemap_mark_tile_dirty(bg_tilemap, offset); +} + +WRITE8_HANDLER( champbas_colorram_w ) +{ + colorram[offset] = data; + tilemap_mark_tile_dirty(bg_tilemap, offset); +} + +WRITE8_HANDLER( champbas_gfxbank_w ) +{ + if (gfxbank != (data & 0x01)) + { + gfxbank = data & 0x01; + tilemap_mark_all_tiles_dirty(ALL_TILEMAPS); + } +} + +WRITE8_HANDLER( champbas_flipscreen_w ) +{ + if (flip_screen != data) + { + flip_screen_set(data); + tilemap_mark_all_tiles_dirty(ALL_TILEMAPS); + } +} + +static TILE_GET_INFO( get_bg_tile_info ) +{ + int code = videoram[tile_index]; + int color = (colorram[tile_index] & 0x1f) + 32; + + SET_TILE_INFO(gfxbank, code, color, 0); +} + +VIDEO_START( champbas ) +{ + bg_tilemap = tilemap_create(get_bg_tile_info, tilemap_scan_rows, + TILEMAP_TYPE_PEN, 8, 8, 32, 32); +} + +static void draw_sprites(running_machine *machine, mame_bitmap *bitmap, const rectangle *cliprect) +{ + int offs; + + for (offs = spriteram_size - 2; offs >= 0; offs -= 2) + { + int code = spriteram[offs] >> 2; + int color = spriteram[offs + 1]; + int flipx = spriteram[offs] & 0x01; + int flipy = spriteram[offs] & 0x02; + int sx = ((256 + 16 - spriteram_2[offs + 1]) & 0xff) - 16; + int sy = spriteram_2[offs] - 16; + + drawgfx(bitmap, + machine->gfx[2 + gfxbank], + code, color, + flipx, flipy, + sx, sy, + cliprect, + TRANSPARENCY_COLOR, 0); + } +} + +VIDEO_UPDATE( champbas ) +{ + tilemap_draw(bitmap, cliprect, bg_tilemap, 0, 0); + draw_sprites(machine, bitmap, cliprect); + return 0; +} |