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AmigActive 10
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AACD 10.iso
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vidhrdw
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dkong.c
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C/C++ Source or Header
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2000-04-19
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11KB
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377 lines
/***************************************************************************
vidhrdw.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
#include "vidhrdw/generic.h"
static int flipscreen;
static int gfx_bank,palette_bank,grid_on;
static const unsigned char *color_codes;
/***************************************************************************
Convert the color PROMs into a more useable format.
Donkey Kong has two 256x4 palette PROMs and one 256x4 PROM which contains
the color codes to use for characters on a per row/column basis (groups of
of 4 characters in the same column - actually row, since the display is
rotated)
The palette PROMs are connected to the RGB output this way:
bit 3 -- 220 ohm resistor -- inverter -- RED
-- 470 ohm resistor -- inverter -- RED
-- 1 kohm resistor -- inverter -- RED
bit 0 -- 220 ohm resistor -- inverter -- GREEN
bit 3 -- 470 ohm resistor -- inverter -- GREEN
-- 1 kohm resistor -- inverter -- GREEN
-- 220 ohm resistor -- inverter -- BLUE
bit 0 -- 470 ohm resistor -- inverter -- BLUE
***************************************************************************/
void dkong_vh_convert_color_prom(unsigned char *palette, unsigned short *colortable,const unsigned char *color_prom)
{
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 < 256;i++)
{
int bit0,bit1,bit2;
/* red component */
bit0 = (color_prom[256] >> 1) & 1;
bit1 = (color_prom[256] >> 2) & 1;
bit2 = (color_prom[256] >> 3) & 1;
*(palette++) = 255 - (0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2);
/* green component */
bit0 = (color_prom[0] >> 2) & 1;
bit1 = (color_prom[0] >> 3) & 1;
bit2 = (color_prom[256] >> 0) & 1;
*(palette++) = 255 - (0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2);
/* blue component */
bit0 = (color_prom[0] >> 0) & 1;
bit1 = (color_prom[0] >> 1) & 1;
*(palette++) = 255 - (0x55 * bit0 + 0xaa * bit1);
color_prom++;
}
color_prom += 256;
/* color_prom now points to the beginning of the character color codes */
color_codes = color_prom; /* we'll need it later */
}
/***************************************************************************
Convert the color PROMs into a more useable format.
Donkey Kong 3 has two 512x8 palette PROMs and one 256x4 PROM which contains
the color codes to use for characters on a per row/column basis (groups of
of 4 characters in the same column - actually row, since the display is
rotated)
Interstingly, bytes 0-255 of the palette PROMs contain an inverted palette,
as other Nintendo games like Donkey Kong, while bytes 256-511 contain a non
inverted palette. This was probably done to allow connection to both the
special Nintendo and a standard monitor.
I don't know the exact values of the resistors between the PROMs and the
RGB output, but they are probably the usual:
bit 7 -- 220 ohm resistor -- inverter -- RED
-- 470 ohm resistor -- inverter -- RED
-- 1 kohm resistor -- inverter -- RED
-- 2.2kohm resistor -- inverter -- RED
-- 220 ohm resistor -- inverter -- GREEN
-- 470 ohm resistor -- inverter -- GREEN
-- 1 kohm resistor -- inverter -- GREEN
bit 0 -- 2.2kohm resistor -- inverter -- GREEN
bit 3 -- 220 ohm resistor -- inverter -- BLUE
-- 470 ohm resistor -- inverter -- BLUE
-- 1 kohm resistor -- inverter -- BLUE
bit 0 -- 2.2kohm resistor -- inverter -- BLUE
***************************************************************************/
void dkong3_vh_convert_color_prom(unsigned char *palette, unsigned short *colortable,const unsigned char *color_prom)
{
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 < 256;i++)
{
int bit0,bit1,bit2,bit3;
/* red component */
bit0 = (color_prom[0] >> 4) & 0x01;
bit1 = (color_prom[0] >> 5) & 0x01;
bit2 = (color_prom[0] >> 6) & 0x01;
bit3 = (color_prom[0] >> 7) & 0x01;
*(palette++) = 255 - (0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3);
/* green component */
bit0 = (color_prom[0] >> 0) & 0x01;
bit1 = (color_prom[0] >> 1) & 0x01;
bit2 = (color_prom[0] >> 2) & 0x01;
bit3 = (color_prom[0] >> 3) & 0x01;
*(palette++) = 255 - (0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3);
/* blue component */
bit0 = (color_prom[256] >> 0) & 0x01;
bit1 = (color_prom[256] >> 1) & 0x01;
bit2 = (color_prom[256] >> 2) & 0x01;
bit3 = (color_prom[256] >> 3) & 0x01;
*(palette++) = 255 - (0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3);
color_prom++;
}
color_prom += 256;
/* color_prom now points to the beginning of the character color codes */
color_codes = color_prom; /* we'll need it later */
}
int dkong_vh_start(void)
{
gfx_bank = 0;
palette_bank = 0;
return generic_vh_start();
}
WRITE_HANDLER( dkongjr_gfxbank_w )
{
if (gfx_bank != (data & 1))
{
gfx_bank = data & 1;
memset(dirtybuffer,1,videoram_size);
}
}
WRITE_HANDLER( dkong3_gfxbank_w )
{
if (gfx_bank != (~data & 1))
{
gfx_bank = ~data & 1;
memset(dirtybuffer,1,videoram_size);
}
}
WRITE_HANDLER( dkong_palettebank_w )
{
int newbank;
newbank = palette_bank;
if (data & 1)
newbank |= 1 << offset;
else
newbank &= ~(1 << offset);
if (palette_bank != newbank)
{
palette_bank = newbank;
memset(dirtybuffer,1,videoram_size);
}
}
WRITE_HANDLER( radarscp_grid_enable_w )
{
grid_on = data & 1;
}
WRITE_HANDLER( radarscp_grid_color_w )
{
int r,g,b;
r = ((~data >> 0) & 0x01) * 0xff;
g = ((~data >> 1) & 0x01) * 0xff;
b = ((~data >> 2) & 0x01) * 0xff;
// palette_change_color(257,r,g,b);
palette_change_color(257,0x00,0x00,0xff);
}
WRITE_HANDLER( dkong_flipscreen_w )
{
if (flipscreen != (~data & 1))
{
flipscreen = ~data & 1;
memset(dirtybuffer,1,videoram_size);
}
}
/***************************************************************************
Draw the game screen in the given osd_bitmap.
Do NOT call osd_update_display() from this function, it will be called by
the main emulation engine.
***************************************************************************/
static void draw_tiles(struct osd_bitmap *bitmap)
{
int offs;
/* for every character in the Video RAM, check if it has been modified */
/* since last time and update it accordingly. */
for (offs = videoram_size - 1;offs >= 0;offs--)
{
if (dirtybuffer[offs])
{
int sx,sy;
int charcode,color;
dirtybuffer[offs] = 0;
sx = offs % 32;
sy = offs / 32;
charcode = videoram[offs] + 256 * gfx_bank;
/* retrieve the character color from the PROM */
color = (color_codes[offs % 32 + 32 * (offs / 32 / 4)] & 0x0f) + 0x10 * palette_bank;
if (flipscreen)
{
sx = 31 - sx;
sy = 31 - sy;
}
drawgfx(tmpbitmap,Machine->gfx[0],
charcode,color,
flipscreen,flipscreen,
8*sx,8*sy,
&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
}
}
/* copy the character mapped graphics */
copybitmap(bitmap,tmpbitmap,0,0,0,0,&Machine->drv->visible_area,TRANSPARENCY_NONE,0);
}
static void draw_sprites(struct osd_bitmap *bitmap)
{
int offs;
/* Draw the sprites. */
for (offs = 0;offs < spriteram_size;offs += 4)
{
if (spriteram[offs])
{
/* spriteram[offs + 2] & 0x40 is used by Donkey Kong 3 only */
/* spriteram[offs + 2] & 0x30 don't seem to be used (they are */
/* probably not part of the color code, since Mario Bros, which */
/* has similar hardware, uses a memory mapped port to change */
/* palette bank, so it's limited to 16 color codes) */
int x,y;
x = spriteram[offs + 3] - 8;
y = 240 - spriteram[offs] + 7;
if (flipscreen)
{
x = 240 - x;
y = 240 - y;
drawgfx(bitmap,Machine->gfx[1],
(spriteram[offs + 1] & 0x7f) + 2 * (spriteram[offs + 2] & 0x40),
(spriteram[offs + 2] & 0x0f) + 16 * palette_bank,
!(spriteram[offs + 2] & 0x80),!(spriteram[offs + 1] & 0x80),
x,y,
&Machine->drv->visible_area,TRANSPARENCY_PEN,0);
/* draw with wrap around - this fixes the 'beheading' bug */
drawgfx(bitmap,Machine->gfx[1],
(spriteram[offs + 1] & 0x7f) + 2 * (spriteram[offs + 2] & 0x40),
(spriteram[offs + 2] & 0x0f) + 16 * palette_bank,
(spriteram[offs + 2] & 0x80),(spriteram[offs + 1] & 0x80),
x-256,y,
&Machine->drv->visible_area,TRANSPARENCY_PEN,0);
}
else
{
drawgfx(bitmap,Machine->gfx[1],
(spriteram[offs + 1] & 0x7f) + 2 * (spriteram[offs + 2] & 0x40),
(spriteram[offs + 2] & 0x0f) + 16 * palette_bank,
(spriteram[offs + 2] & 0x80),(spriteram[offs + 1] & 0x80),
x,y,
&Machine->drv->visible_area,TRANSPARENCY_PEN,0);
/* draw with wrap around - this fixes the 'beheading' bug */
drawgfx(bitmap,Machine->gfx[1],
(spriteram[offs + 1] & 0x7f) + 2 * (spriteram[offs + 2] & 0x40),
(spriteram[offs + 2] & 0x0f) + 16 * palette_bank,
(spriteram[offs + 2] & 0x80),(spriteram[offs + 1] & 0x80),
x+256,y,
&Machine->drv->visible_area,TRANSPARENCY_PEN,0);
}
}
}
}
static void draw_grid(struct osd_bitmap *bitmap)
{
const unsigned char *table = memory_region(REGION_GFX3);
int x,y,counter;
counter = flipscreen ? 0x000 : 0x400;
x = Machine->drv->visible_area.min_x;
y = Machine->drv->visible_area.min_y;
while (y <= Machine->drv->visible_area.max_y)
{
x = 4 * (table[counter] & 0x7f);
if (x >= Machine->drv->visible_area.min_x &&
x <= Machine->drv->visible_area.max_x)
{
if (table[counter] & 0x80) /* star */
{
if (rand() & 1) /* noise coming from sound board */
plot_pixel(bitmap,x,y,Machine->pens[256]);
}
else if (grid_on) /* radar */
plot_pixel(bitmap,x,y,Machine->pens[257]);
}
counter++;
if (x >= 4 * (table[counter] & 0x7f))
y++;
}
}
void radarscp_vh_screenrefresh(struct osd_bitmap *bitmap,int full_refresh)
{
palette_change_color(256,0xff,0x00,0x00); /* stars */
if (palette_recalc())
memset(dirtybuffer,1,videoram_size);
draw_tiles(bitmap);
draw_grid(bitmap);
draw_sprites(bitmap);
}
void dkong_vh_screenrefresh(struct osd_bitmap *bitmap,int full_refresh)
{
draw_tiles(bitmap);
draw_sprites(bitmap);
}