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author sasuke-arcade <58130089+sasuke-arcade@users.noreply.github.com>2019-11-27 23:48:13 +0900
committer Angelo Salese <angelosa@users.noreply.github.com>2019-11-27 15:48:13 +0100
commit9216ceca6473c7ae27ed9ca0fdc2e89650043b4e (patch)
treeb56f6759451d69b77375c929cddc794e01869c68
parente2358318322e3286f673677da02c53ed2f7a6120 (diff)
skyfox.cpp : Improve background based on PCB (#5976)
* skyfox.cpp : Improve background based on PCB The previous background implementation was completely wrong. I found stars position stored in memory. I used this to rewrite the background drawing code. Reference PCB video: - https://www.youtube.com/watch?v=oyE1CfcVrDc - https://www.youtube.com/watch?v=5QhTNrNH-CU * Remove debug code. * Organize code and adjust display - Split background VRAM and work RAM from addresses map - Rename DECLARE_WRITE8_MEMBER - Remove unused interupt declarations - Adjust background star display * Fixed problems with flipscreen - Adjust sprite position - Remove background flip
-rw-r--r--src/mame/drivers/skyfox.cpp18
-rw-r--r--src/mame/includes/skyfox.h8
-rw-r--r--src/mame/video/skyfox.cpp39
3 files changed, 29 insertions, 36 deletions
diff --git a/src/mame/drivers/skyfox.cpp b/src/mame/drivers/skyfox.cpp
index 84c67c0171f..9914d127034 100644
--- a/src/mame/drivers/skyfox.cpp
+++ b/src/mame/drivers/skyfox.cpp
@@ -33,7 +33,7 @@ Verified Dip locations and recommended settings with manual
***************************************************************************/
-WRITE8_MEMBER(skyfox_state::skyfox_vregs_w)
+WRITE8_MEMBER(skyfox_state::output_w)
{
switch (offset)
{
@@ -55,11 +55,12 @@ void skyfox_state::skyfox_map(address_map &map)
map(0x0000, 0xbfff).rom();
map(0xc000, 0xcfff).ram();
map(0xd000, 0xd3ff).ram().share("spriteram");
- map(0xd400, 0xdfff).ram(); // ?
+ map(0xd400, 0xd4ff).ram().share("bgram"); // For background stars
+ map(0xd500, 0xdfff).ram();
map(0xe000, 0xe000).portr("INPUTS");
map(0xe001, 0xe001).portr("DSW0");
map(0xe002, 0xe002).portr("DSW1");
- map(0xe008, 0xe00f).w(FUNC(skyfox_state::skyfox_vregs_w));
+ map(0xe008, 0xe00f).w(FUNC(skyfox_state::output_w));
map(0xf001, 0xf001).portr("DSW2");
}
@@ -204,21 +205,13 @@ GFXDECODE_END
/* Scroll the background on every vblank (guess). */
-INTERRUPT_GEN_MEMBER(skyfox_state::skyfox_interrupt)
-{
- /* Scroll the bg */
- m_bg_pos += (m_bg_ctrl >> 1) & 0x7; // maybe..
-}
-
void skyfox_state::machine_start()
{
- save_item(NAME(m_bg_pos));
save_item(NAME(m_bg_ctrl));
}
void skyfox_state::machine_reset()
{
- m_bg_pos = 0;
m_bg_ctrl = 0;
}
@@ -227,7 +220,6 @@ void skyfox_state::skyfox(machine_config &config)
/* basic machine hardware */
Z80(config, m_maincpu, XTAL(8'000'000)/2); /* Verified at 4MHz */
m_maincpu->set_addrmap(AS_PROGRAM, &skyfox_state::skyfox_map);
- m_maincpu->set_vblank_int("screen", FUNC(skyfox_state::skyfox_interrupt));
Z80(config, m_audiocpu, XTAL(14'318'181)/8); /* Verified at 1.789772MHz */
m_audiocpu->set_addrmap(AS_PROGRAM, &skyfox_state::skyfox_sound_map);
@@ -242,7 +234,7 @@ void skyfox_state::skyfox(machine_config &config)
m_screen->set_palette(m_palette);
GFXDECODE(config, m_gfxdecode, m_palette, gfx_skyfox);
- PALETTE(config, m_palette, FUNC(skyfox_state::skyfox_palette), 256+256); // 256 static colors (+256 for the background??)
+ PALETTE(config, m_palette, FUNC(skyfox_state::skyfox_palette), 256); // 256 static colors
/* sound hardware */
SPEAKER(config, "mono").front_center();
diff --git a/src/mame/includes/skyfox.h b/src/mame/includes/skyfox.h
index 85baf20e8b8..1f93181d49d 100644
--- a/src/mame/includes/skyfox.h
+++ b/src/mame/includes/skyfox.h
@@ -25,7 +25,8 @@ public:
m_screen(*this, "screen"),
m_palette(*this, "palette"),
m_soundlatch(*this, "soundlatch"),
- m_spriteram(*this, "spriteram")
+ m_spriteram(*this, "spriteram"),
+ m_bgram(*this, "bgram")
{ }
void skyfox(machine_config &config);
@@ -43,16 +44,15 @@ private:
required_device<palette_device> m_palette;
required_device<generic_latch_8_device> m_soundlatch;
required_shared_ptr<uint8_t> m_spriteram;
+ required_shared_ptr<uint8_t> m_bgram;
- int m_bg_pos;
int m_bg_ctrl;
- DECLARE_WRITE8_MEMBER(skyfox_vregs_w);
+ DECLARE_WRITE8_MEMBER(output_w);
virtual void machine_start() override;
virtual void machine_reset() override;
void skyfox_palette(palette_device &palette) const;
uint32_t screen_update_skyfox(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect);
- INTERRUPT_GEN_MEMBER(skyfox_interrupt);
void draw_sprites( bitmap_ind16 &bitmap, const rectangle &cliprect );
void draw_background(bitmap_ind16 &bitmap, const rectangle &cliprect);
diff --git a/src/mame/video/skyfox.cpp b/src/mame/video/skyfox.cpp
index 70c52e80932..f751ab7863e 100644
--- a/src/mame/video/skyfox.cpp
+++ b/src/mame/video/skyfox.cpp
@@ -83,10 +83,6 @@ void skyfox_state::skyfox_palette(palette_device &palette) const
compute_res_net_all(rgb, color_prom, skyfox_decode_info, skyfox_net_info);
palette.set_pen_colors(0, rgb);
-
- // Grey scale for the background??? is wrong
- for (int i = 0; i < 256; i++)
- palette.set_pen_color(i + 256, rgb_t(i, i, i));
}
@@ -153,8 +149,8 @@ void skyfox_state::draw_sprites( bitmap_ind16 &bitmap, const rectangle &cliprect
if (m_bg_ctrl & 1) // flipscreen
{
- x = width - x - (n - 1) * 8;
- y = height - y - (n - 1) * 8;
+ x = width - x - n * 8;
+ y = height - y - n * 8;
flipx = !flipx;
flipy = !flipy;
}
@@ -196,26 +192,31 @@ void skyfox_state::draw_background(bitmap_ind16 &bitmap, const rectangle &clipre
{
uint8_t *rom = memregion("gfx2")->base();
- /* The foreground stars (sprites) move at twice this speed when
- the bg scroll rate [e.g. (m_bg_ctrl >> 1) & 7] is 4 */
- int pos = (m_bg_pos >> 4) & (512 * 2 - 1);
+ /* Flashing stops until the first star moves after turning on the power */
+ bool shining = (m_bg_ctrl & 0x8);
+ /* Maybe star pattern change. This will change at some intervals or when restart */
+ int pattern = (m_bg_ctrl & 0x6) >> 1;
for (int i = 0; i < 0x1000; i++)
{
- int offs = (i * 2 + ((m_bg_ctrl >> 4) & 0x3) * 0x2000) % 0x8000;
+ /* contains the position of stars from 0xd4e0 in RAM */
+ int ramoffset = 0xe0 + (i & 0xf) * 2;
+ int pos = m_bgram[ramoffset + 1] * 2 + ((m_bgram[ramoffset] & 0x80) ? 1 : 0);
+
+ /* ROM offset of star pattern */
+ int offs = (i * 2) % 0x2000 + pattern * 0x2000;
+ /* Looks like good, but was written with intuition, Probably not perfect */
int pen = rom[offs];
- int x = rom[offs + 1] * 2 + (i & 1) + pos + ((i & 8) ? 512 : 0);
- int y = ((i / 8) / 2) * 8 + (i % 8);
+ int x = rom[offs + 1] * 2 + ((i >> 4) & 1) + pos;
+ int y = (i >> 4);
+ x += 0x60; // Adjustment based on PCB display
- if (m_bg_ctrl & 1) // flipscreen
- {
- x = 512 * 2 - (x % (512 * 2));
- y = 256 - (y % 256);
- }
+ // When flipscreen is enabled, direction of background scroll is reversed by the in-game subroutine.
+ // This PCB seems does not support background flip.
- for (int j = 0; j <= ((pen & 0x80) ? 0 : 3); j++)
- bitmap.pix16((((j / 2) & 1) + y) % 256, ((j & 1) + x) % 512) = 256 + (pen & 0x7f);
+ if (((m_bg_ctrl >> 4) & 3) != (pen & 3) || !shining)
+ bitmap.pix16(y % 256, x % 512) = pen;
}
}