diff options
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 |
commit | 9216ceca6473c7ae27ed9ca0fdc2e89650043b4e (patch) | |
tree | b56f6759451d69b77375c929cddc794e01869c68 /src/mame/video | |
parent | e2358318322e3286f673677da02c53ed2f7a6120 (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
Diffstat (limited to 'src/mame/video')
-rw-r--r-- | src/mame/video/skyfox.cpp | 39 |
1 files changed, 20 insertions, 19 deletions
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; } } |