Super Mario Bros./Notes

The following article is a Notes Page for Super Mario Bros..

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

Main Palettes

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)

• Water
• Ground
• Underground
• Castle

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)

Other

• Mushroom type sets pipe color (over rides all other pipe color settings)
• Bowser has special palette

Metatile list

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