Physics

General

• No object can exert direct force on any other (except resistance).
• The player has limited inventory based solely on the number of items.
• Inventory contents have no physical effect.
• Mouse clicks must be within an object's visible graphic area to target it.

Object Classes

Each class has distinct game mechanics governing its in-game behaviour.

Tiles

• Tiles are persistent objects, meaning that they stay in the world where they were last placed regardless of player activity.
• They can be kept in the player's inventory, placed in the world, and with the exception of townstones, picked up again by their owner.
• Tiles can only be placed according to a horizontal grid of cells.

Many tiles are 8 pixels high with 16x16 pixel base, and it is sometimes convenient to describe them as "half-tiles", since 16 pixels is conventionally a whole unit in any direction.

Additionally,

• All tiles can be equipped by selecting them from inventory, making them active.
• All equippable items are tiles.

There are two basic kinds of tile.

Blocks

Blocks are tiles typically placed in the world as part of permanent constructions.
Their appearance conforms to their role as 3d objects, and they are solid where they appear to be.

Equipment

Equipment includes tiles that enhance a character's abilities, and are typically kept with them.
If placed in the world, they are transparent but solid half-tiles with their 2d graphic on the top face.

Only the weapons fall in this category, and are active equipment, controlled with the spacebar.
During use, they are displayed on the character with appropriate animations.

Entities

• Entities exist only while a player is active, and can spawn and despawn according to certain rules.
• They can not be equipped, kept, or manipulated like tiles.
• Entities are not bound to grid positions.

There are two basic kinds of entity.

Characters

Player and non-player characters, both benign and hostile.
Characters interact physically as solid objects shorter than their apparent size.
They are subject to gravity, and will fall if unsupported.

Characters can use equipment with physical effects:
Weapons allow them to attack and kill other characters (where allowed).

Accessories are extensions to the character's appearance that can be added and removed freely.
They are not kept in inventory, but are accessed via the shop interface.

Drops

Drops are entities that are displayed in-world for collection only with no other physical attributes.
They do not appear as inventory items when collected but have some other effect.

Coins are the only in-game drops. They can be collected using the mouse or by a player character standing on them, which increments the player's gold count.

Character Movement

Note: details are based on in-game experiments and may be imprecise.

Walking

• Speeds in x and y directions are independent, meaning that they are not adjusted for diagonal movement.
• Horizontal speed is not affected by climbing, falling, or attacking.

Speed depends on the material being walked on:

• approx. 5.5 spans per second normally
• 2x normal on road blocks
• 1/2 normal on sand blocks

Climbing and Falling

• Characters can walk over physical obstacles of 8 pixels, but not 12 pixels.
• They can walk while falling.
• Descent speed while falling is 3/4 of walking speed.

Crossing gaps

Climbing, falling, and crossing gaps.

Player characters do not begin falling until 12 pixels past supporting ground, which adds 9 pixels to the height at which they can land after crossing a gap and climbing.

Relative maximum landing height

Where gap is the number of cells, 17 - gap * 12 pixels.
But since only multiples of 4 pixels are actually usable, it is more practical to use

16 - gap x 12  pixels

Obstruction

Characters can not move through solid obstacles.

They have a solid area at their base smaller than their graphic area, with estimated dimensions (pixels):

Character hit-box

height	width	depth	5 .. 8	12	0 .. 1

They can walk into a vertical space of 8 pixels, but not 4 pixels.

Special case: They can climb through a diagonal join walking north or south, but not reliably. This behaviour might not be preserved in future updates.