Super Mario Bros.:Notes
Player physics/movement algorithm
- Signed vertical velocity in whole pixels at 0x009F
- Unsigned(?) vertical velocity in fractions of a pixel at 0x0433
- Unsigned gravity acceleration (0xA8) at 0x0000 (note: only has the correct value inside the routine)
- If the player sprite is not grounded (in air), then
- The gravity (0xA8) is added to 0x0433 with ADC.
- If the carry flag is set (i.e. fraction overflowed), a whole pixel (0x01) is added to 0x009F.
- This gives the player sprite almost standard 8:8 fixed point vertical physics. But the fractions seem to be unsigned always?
- Note: 0x009F is clamped to a maximum positive value of 0x05, but 0x0433 is NOT cleared. This could lead to various round-off errors leading into the next jump (unconfirmed).
Hacking the End-of-Level Castles
1) Get some graphing paper, and start cordoning 2x2 squares. Make a 5x5 block of such squares (10x10 overall).
2) Reading right-to-left, from the top row down, you've got the metatile defined by $17DF, $17E0, $17E1, etc......, $17F7.
3) This linear string of 25 bytes can be represented on your graph paper like this:
5 4 3 2 1 10 9 8 7 6 15 14 13 12 11 20 19 18 17 16 25 24 23 22 21
The first byte in this string codes for the upper-rightmost metatile, the second byte codes for the metatile directly to #'s left, etc.
4) The large castles at the end of every X-3 level (and the beginning of most X-1 levels) are simply the small castle stacked on top of another, slightly taller one. This taller castle is 6 metatiles high and five metatiles wide, and is coded in a similar right-to-left, top-down fashion. Its linear byte sequence begins at $17F8.
5) The little side-sections on the X-3 castle type are actually the same background image that occurs throughout World 8-3. This image is 1 metatile wide and eleven metatiles high (although it only appears to be six metatiles high since the first five bytes are assigned transparent "00" values). Its coding begins at $13CE and ends at $13D8.
Mario Palette Information
There are four main palettes each with a unique set of 8 colors defined (background, pipe, cloud, brick, mario, green enemy, red enemy, brown enemy)
4 alternate palettes
- Night (sets background)
- Snow (sets background, pipe color)
- Night/Snow 1 (sets background, pipe colors)
- Night/Snow 2 (uses castle palette for everything but background)
- Mushroom type sets pipe color (over rides all other pipe color settings)
- Bowser has special palette
00 - Blank 01 - Black Metatile 02 - Bush Left 03 - Bush Middle 04 - Bush Right 05 - Mountain Left 06 - Mountain Left Bottom/Middle Center 07 - Mountain Middle Top 08 - Mountain Right 09 - Mountain Right Bottom 0A - Mountain Middle Bottom 0B - Bridge Guardrail 0C - Chain 0D - Tall Tree Top, Top Half 0E - Short Tree Top 0F - Tall Tree Top, Bottom Half 10 - Warp Pipe End Left, Points Up 11 - Warp Pipe End Right, Points Up 12 - Decoration Pipe End Left, Points Up 13 - Decoration Pipe End Right, Points Up 14 - Pipe Shaft Left 15 - Pipe Shaft Right 16 - Tree Ledge Left Edge 17 - Tree Ledge Middle 18 - Tree Ledge Right Edge 19 - Mushroom Left Edge 1A - Mushroom Middle 1B - Mushroom Right Edge 1C - Sideways Pipe End Top 1D - Sideways Pipe Shaft Top 1E - Sideways Pipe Joint Top 1F - Sideways Pipe End Bottom 20 - Sideways Pipe Shaft Bottom 21 - Sideways Pipe Joint Bottom 22 - Seaplant 23 - Blank, Used On Bricks Or Blocks That Are Hit 24 - Flagpole Ball 25 - Flagpole Shaft 26 - Blank, Used In Conjunction With Vines 40 - Vertical Rope 41 - Horizontal Rope 42 - Left Pulley 43 - Right Pulley 44 - Blank Used For Balance Rope 45 - Castle Top 46 - Castle Window Left 47 - Castle Brick Wall 48 - Castle Window Right 49 - Castle Top W/ Brick 4A - Entrance Top 4B - Entrance Bottom 4C - Green Ledge Stump 4D - Fence 4E - Tree Trunk 4F - Mushroom Stump Top 50 - Mushroom Stump Bottom 51 - Breakable Brick W/ Line 52 - Breakable Brick 53 - Breakable Brick (Not Used) 54 - Cracked Rock Terrain 55 - Brick With Line (Power-Up) 56 - Brick With Line (Vine) 57 - Brick With Line (Star) 58 - Brick With Line (Coins) 59 - Brick With Line (1-Up) 5A - Brick (Power-Up) 5B - Brick (Vine) 5C - Brick (Star) 5D - Brick (Coins) 5E - Brick (1-Up) 5F - Hidden Block (1 Coin) 60 - Hidden Block (1-Up) 61 - Solid Block (3-D Block) 62 - Solid Block (White Wall) 63 - Bridge 64 - Bullet Bill Cannon Barrel 65 - Bullet Bill Cannon Top 66 - Bullet Bill Cannon Bottom 67 - Blank Used For Jumpspring 68 - Half Brick Used For Jumpspring 69 - Solid Block (Water Level, Green Rock) 6A - Half Brick (???) 6B - Water Pipe Top 6C - Water Pipe Bottom 6D - Flag Ball (Residual Object) 80 - Cloud Left 81 - Cloud Middle 82 - Cloud Right 83 - Cloud Bottom Left 84 - Cloud Bottom Middle 85 - Cloud Bottom Right 86 - Water/Lava Top 87 - Water/Lava 88 - Cloud Level Terrain 89 - Bowser's Bridge C0 - Question Block (Coin) C1 - Question Block (Power-Up) C2 - Coin C3 - Underwater Coin C4 - Empty Block C5 - Axe