title: Function overview slug: docs-ptc-function system: Petit Computer type: reference source: https://smilebasicsource.com/forum/thread/docs-ptc-function content_id: 19764 created: 2025-08-02 scraped: 2026-06-21 #

Function overview #

Functions are used to perform calculations or to read values. The distinction of a function from a command is the single returned value.

Functions can be passed zero or more arguments, with each argument being separated by a comma. If no arguments are passed, the closing parenthesis is placed immediately after the opening parenthesis.

Functions have the highest level of precedence aside from parenthesized statements. See Operator overview.

Function table #

Mathematical functions #

`ABS(number)`	Calculates the absolute value of a number.
`ATAN(tangent)`	Calculates the arctangent of a value. Returns results in radians.
`ATAN(y, x)`	Calculates the angle from the X-axis of a coordinate pair in radians.
`COS(angle)`	Calculates the cosine of the given angle. `angle` is in radians.
`DEG(radians)`	Converts an angle in radians into an angle in degrees.
`EXP(exponent)`	Calculates e raised to the power of `exponent`
`FLOOR(number)`	Rounds number to the next lowest integer
`LOG(number)`	Calculates the natural logarithm of the number
`PI()`	Returns the approximate value of pi. Returns 12867/4096, or about 3.141.
`POW(base, exponent)`	Calculates the value of `base` raised to the power of `exponent`.
`RAD(degrees)`	Converts an angle in degrees into an angle in radians.
`RND(maximum)`	Generates a pseudorandom integer between 0 and `maximum`
`SGN(number)`	Calculates the sign of the number.
`SIN(angle)`	Calculates the sine of the given angle. `angle` is given in radians.
`SQR(number)`	Calculates the square root of the number.
`TAN(angle)`	Calculates the tangent of given angle. `angle` is given in radians.

String functions #

`ASC(string)`	Returns the character code of the first character in the string.
`CHR$(code)`	Returns a single character string corresponding to the character code.
`HEX$(number)`	Converts a number into a hexadecimal string representation.
`HEX$(number,digits)`	Converts a number into a hexadecimal string represnetation with a specific number of digits
`INSTR(string, substring)`	Searches within a string for a substring, returning the index if found, or -1 if not found
`INSTR(string, substring, start)`	Searches within a string for a substring starting from index `start`, returning the index `substring` is found at, or -1 if not found.
`LEFT$(string, length)`	Returns a substring consisting of the `length` left-most characters
`LEN(string)`	Returns the number of characters in the string
`MID$(string, start, length)`	Returns a substring consisting of the `length` characters starting from index `start`.
`RIGHT$(string, length)`	Returns a substring consisting of the `length` right-most characters.
`STR$(number)`	Converts a number into a decimal string representation.
`SUBST$(string, start, count, replacement)`	Returns a new string, replacing part of `string` with `replacement`.
`VAL(string)`	Converts a string into a number.

System functions #

These are functions that interact with other subsystems of Petit Computer, such as the graphics or audio systems.

Background #

`BGCHK(layer)`	Checks if the BG layer specified is currently animated.

Audio #

`BGMCHK()`	Checks if background music is playing on track 0.
`BGMCHK(track)`	Checks if a specific background music track is in use.
`BGMGETV(var)`	Gets the value of a MML variable.
`TALKCHK()`	Checks if the speech synthesis system is currently active. On English copies of Petit Computer, always returns 0.

User input #

`BTRIG()`	Checks if a button is pressed, with repeat checking. Identical to BUTTON(1).
`BUTTON()`	Checks if a button is currently pressed.
`BUTTON(type)`	Checks buttons pressed, held, or released depending on type.
`INKEY$()`	Retrieve character input from the keyboard

Console #

`CHKCHR(x, y)`	Gets the character code of a location on the text console.

Graphics #

`GSPOIT(x, y)`	Gets the color of a location on the graphics page
`GSPOIT(x, y, page)`	Gets the color of a location on a specific graphics page

Panel #

`ICONCHK()`	Checks if a panel icon is pressed

Sprite #

`SPCHK(id)`	Checks the animationstatus of a sprite.
`SPGETV(id, var)`	Gets the value of a sprite variable.
`SPHIT(id)`	Checks for collisions between the sprite `id` with other sprites. Returns 1 if there is a collision, and sets some system variables.
`SPHIT(id, start)`	Checks for collisions between sprite `id` and sprites with IDs greater than `start`. Returns 1 if there is a collision, and sets some system variables.
`SPHITRC(id, x, y, width, height)`	Checks for collision between a sprite and a rectangular region.
`SPHITRC(id, x, y, width, height, dx, dy)`	Checks for collision between a sprite and a rectangular region, accounting for motion of the rectangle.
`SPHITSP(id, other)`	Checks for collision between two specific sprites, returning 1 if collision occurs.