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-rw-r--r--src/mame/video/circusc.c199
1 files changed, 199 insertions, 0 deletions
diff --git a/src/mame/video/circusc.c b/src/mame/video/circusc.c
new file mode 100644
index 00000000000..242ef0111d2
--- /dev/null
+++ b/src/mame/video/circusc.c
@@ -0,0 +1,199 @@
+/***************************************************************************
+
+ video.c
+
+ Functions to emulate the video hardware of the machine.
+
+***************************************************************************/
+
+#include "driver.h"
+
+
+
+UINT8 *circusc_videoram,*circusc_colorram;
+static tilemap *bg_tilemap;
+
+UINT8 *circusc_spritebank;
+UINT8 *circusc_scroll;
+
+
+
+/***************************************************************************
+
+ Convert the color PROMs into a more useable format.
+
+ Circus Charlie has one 32x8 palette PROM and two 256x4 lookup table PROMs
+ (one for characters, one for sprites).
+ 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( circusc )
+{
+ 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 */
+
+ /* sprites */
+ for (i = 0;i < TOTAL_COLORS(1);i++)
+ COLOR(1,i) = *(color_prom++) & 0x0f;
+
+ /* characters */
+ for (i = 0;i < TOTAL_COLORS(0);i++)
+ COLOR(0,i) = (*(color_prom++) & 0x0f) + 0x10;
+}
+
+
+
+/***************************************************************************
+
+ Callbacks for the TileMap code
+
+***************************************************************************/
+
+static TILE_GET_INFO( get_tile_info )
+{
+ UINT8 attr = circusc_colorram[tile_index];
+ tileinfo->category = (attr & 0x10) >> 4;
+ SET_TILE_INFO(
+ 0,
+ circusc_videoram[tile_index] + ((attr & 0x20) << 3),
+ attr & 0x0f,
+ TILE_FLIPYX((attr & 0xc0) >> 6));
+}
+
+
+
+/***************************************************************************
+
+ Start the video hardware emulation.
+
+***************************************************************************/
+
+VIDEO_START( circusc )
+{
+ bg_tilemap = tilemap_create(get_tile_info,tilemap_scan_rows,TILEMAP_TYPE_PEN,8,8,32,32);
+
+ tilemap_set_scroll_cols(bg_tilemap,32);
+}
+
+
+
+/***************************************************************************
+
+ Memory handlers
+
+***************************************************************************/
+
+WRITE8_HANDLER( circusc_videoram_w )
+{
+ circusc_videoram[offset] = data;
+ tilemap_mark_tile_dirty(bg_tilemap,offset);
+}
+
+WRITE8_HANDLER( circusc_colorram_w )
+{
+ circusc_colorram[offset] = data;
+ tilemap_mark_tile_dirty(bg_tilemap,offset);
+}
+
+WRITE8_HANDLER( circusc_flipscreen_w )
+{
+ flip_screen_set(data & 1);
+}
+
+
+
+/***************************************************************************
+
+ Display refresh
+
+***************************************************************************/
+
+static void draw_sprites(running_machine *machine, mame_bitmap *bitmap, const rectangle *cliprect)
+{
+ int offs;
+ UINT8 *sr;
+
+
+ if ((*circusc_spritebank & 0x01) != 0)
+ sr = spriteram;
+ else sr = spriteram_2;
+
+ for (offs = 0; offs < spriteram_size;offs += 4)
+ {
+ int sx,sy,flipx,flipy;
+
+
+ sx = sr[offs + 2];
+ sy = sr[offs + 3];
+ flipx = sr[offs + 1] & 0x40;
+ flipy = sr[offs + 1] & 0x80;
+ if (flip_screen)
+ {
+ sx = 240 - sx;
+ sy = 240 - sy;
+ flipx = !flipx;
+ flipy = !flipy;
+ }
+
+
+ drawgfx(bitmap,machine->gfx[1],
+ sr[offs + 0] + 8 * (sr[offs + 1] & 0x20),
+ sr[offs + 1] & 0x0f,
+ flipx,flipy,
+ sx,sy,
+ cliprect,TRANSPARENCY_COLOR,0);
+
+ }
+}
+
+VIDEO_UPDATE( circusc )
+{
+ int i;
+
+ for (i = 0;i < 10;i++)
+ tilemap_set_scrolly(bg_tilemap,i,0);
+ for (i = 10;i < 32;i++)
+ tilemap_set_scrolly(bg_tilemap,i,*circusc_scroll);
+
+ tilemap_draw(bitmap,cliprect,bg_tilemap,1,0);
+ draw_sprites(machine,bitmap,cliprect);
+ tilemap_draw(bitmap,cliprect,bg_tilemap,0,0);
+ return 0;
+}