/***************************************************************************

  video.c

  Functions to emulate the video hardware of the machine.

***************************************************************************/

#include "emu.h"
#include "includes/kchamp.h"


PALETTE_INIT( kchamp )
{
	int i, red, green, blue;

	for (i = 0; i < machine->total_colors(); i++)
	{
		red = color_prom[i];
		green = color_prom[machine->total_colors() + i];
		blue = color_prom[2 * machine->total_colors() + i];

		palette_set_color_rgb(machine, i, pal4bit(red), pal4bit(green), pal4bit(blue));
	}
}

WRITE8_HANDLER( kchamp_videoram_w )
{
	kchamp_state *state = (kchamp_state *)space->machine->driver_data;
	state->videoram[offset] = data;
	tilemap_mark_tile_dirty(state->bg_tilemap, offset);
}

WRITE8_HANDLER( kchamp_colorram_w )
{
	kchamp_state *state = (kchamp_state *)space->machine->driver_data;
	state->colorram[offset] = data;
	tilemap_mark_tile_dirty(state->bg_tilemap, offset);
}

WRITE8_HANDLER( kchamp_flipscreen_w )
{
	flip_screen_set(space->machine, data & 0x01);
}

static TILE_GET_INFO( get_bg_tile_info )
{
	kchamp_state *state = (kchamp_state *)machine->driver_data;
	int code = state->videoram[tile_index] + ((state->colorram[tile_index] & 7) << 8);
	int color = (state->colorram[tile_index] >> 3) & 0x1f;

	SET_TILE_INFO(0, code, color, 0);
}

VIDEO_START( kchamp )
{
	kchamp_state *state = (kchamp_state *)machine->driver_data;
	state->bg_tilemap = tilemap_create(machine, get_bg_tile_info, tilemap_scan_rows, 8, 8, 32, 32);
}

/*
        Sprites
        -------
        Offset        Encoding
             0        YYYYYYYY
             1        TTTTTTTT
             2        FGGTCCCC
             3        XXXXXXXX
*/

static void kchamp_draw_sprites( running_machine *machine, bitmap_t *bitmap, const rectangle *cliprect )
{
	kchamp_state *state = (kchamp_state *)machine->driver_data;
	UINT8 *spriteram = state->spriteram;
	int offs;

	for (offs = 0; offs < 0x100; offs += 4)
	{
		int attr = spriteram[offs + 2];
		int bank = 1 + ((attr & 0x60) >> 5);
		int code = spriteram[offs + 1] + ((attr & 0x10) << 4);
		int color = attr & 0x0f;
		int flipx = 0;
		int flipy = attr & 0x80;
		int sx = spriteram[offs + 3] - 8;
		int sy = 247 - spriteram[offs];

		if (flip_screen_get(machine))
		{
			sx = 240 - sx;
			sy = 240 - sy;
			flipx = !flipx;
			flipy = !flipy;
		}

		drawgfx_transpen(bitmap, cliprect, machine->gfx[bank], code, color, flipx, flipy, sx, sy, 0);
	}
}

static void kchampvs_draw_sprites( running_machine *machine, bitmap_t *bitmap, const rectangle *cliprect )
{
	kchamp_state *state = (kchamp_state *)machine->driver_data;
	UINT8 *spriteram = state->spriteram;
	int offs;

	for (offs = 0; offs < 0x100; offs += 4)
	{
		int attr = spriteram[offs + 2];
		int bank = 1 + ((attr & 0x60) >> 5);
		int code = spriteram[offs + 1] + ((attr & 0x10) << 4);
		int color = attr & 0x0f;
		int flipx = 0;
		int flipy = attr & 0x80;
		int sx = spriteram[offs + 3];
		int sy = 240 - spriteram[offs];

		if (flip_screen_get(machine))
		{
			sx = 240 - sx;
			sy = 240 - sy;
			flipx = !flipx;
			flipy = !flipy;
		}

		drawgfx_transpen(bitmap, cliprect, machine->gfx[bank], code, color, flipx, flipy, sx, sy, 0);
	}
}


VIDEO_UPDATE( kchamp )
{
	kchamp_state *state = (kchamp_state *)screen->machine->driver_data;

	tilemap_draw(bitmap, cliprect, state->bg_tilemap, 0, 0);
	kchamp_draw_sprites(screen->machine, bitmap, cliprect);
	return 0;
}

VIDEO_UPDATE( kchampvs )
{
	kchamp_state *state = (kchamp_state *)screen->machine->driver_data;

	tilemap_draw(bitmap, cliprect, state->bg_tilemap, 0, 0);
	kchampvs_draw_sprites(screen->machine, bitmap, cliprect);
	return 0;
}
