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-rw-r--r--src/mame/video/champbas.c151
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
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+++ b/src/mame/video/champbas.c
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+/***************************************************************************
+
+ 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;
+}