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DirectGPU (WIP)

Metaballs

Metaball methods provide support for creating and rendering smooth organic shapes made from multiple interacting points.

A metaball system contains multiple metaballs that can be moved, colored, and simulated with optional physics.

Methods

Section titled “Methods”
Method
addMetaball(systemId : number, x : number, y : number, radius : number, strength : number) : number
clearMetaballs(systemId : number) : ()
createMetaballSystem(displayId : DisplayID) : number
getMetaballCount(systemId : number) : number
getMetaballInfo(systemId : number, ballId : number) : table
removeMetaballSystem(systemId : number) : ()
renderMetaballs(systemId : number, threshold : number, renderMode : number) : ()
setMetaballColor(systemId : number, ballId : number, r : number, g : number, b : number) : ()
setMetaballPhysics(systemId : number, enabled : boolean, gravity : number, drag : number) : ()
setMetaballVelocity(systemId : number, ballId : number, vx : number, vy : number) : ()
updateMetaballs(systemId : number, deltaTime : number) : ()

Usage

Section titled “Usage”

createMetaballSystem

Section titled “createMetaballSystem”

Creates a new metaball system attached to a display.

Returns: systemId : number

Example
Section titled “Example”
local systemId = gpu.createMetaballSystem(displayId)

addMetaball

Section titled “addMetaball”

Adds a metaball to an existing system.

Returns: ballId : number

Example
Section titled “Example”
local ballId = gpu.addMetaball(
    systemId,
    50,
    50,
    20,
    1.0
)

clearMetaballs

Section titled “clearMetaballs”

Removes all metaballs from a system.

Example
Section titled “Example”
gpu.clearMetaballs(systemId)

getMetaballCount

Section titled “getMetaballCount”

Returns the number of metaballs currently in a system.

Example
Section titled “Example”
print(gpu.getMetaballCount(systemId))

getMetaballInfo

Section titled “getMetaballInfo”

Returns information about a specific metaball.

Requires: systemId : number, ballId : number

Returns: Metaball information table.

Example
Section titled “Example”
local info = gpu.getMetaballInfo(
    systemId,
    ballId
)


print(info)

removeMetaballSystem

Section titled “removeMetaballSystem”

Deletes an entire metaball system.

Use this when the system is no longer needed.

Example
Section titled “Example”
gpu.removeMetaballSystem(systemId)

renderMetaballs

Section titled “renderMetaballs”

Renders a metaball system.

threshold controls the surface cutoff value.

renderMode controls the rendering mode.

Example
Section titled “Example”
gpu.renderMetaballs(
    systemId,
    1.0,
    0
)

setMetaballColor

Section titled “setMetaballColor”

Changes the color of a metaball.

Example
Section titled “Example”
gpu.setMetaballColor(
    systemId,
    ballId,
    0,
    255,
    255
)

setMetaballPhysics

Section titled “setMetaballPhysics”

Enables or disables metaball physics.

Parameters:

  • enabled - whether physics simulation is active
  • gravity - gravity strength
  • drag - movement resistance
Example
Section titled “Example”
gpu.setMetaballPhysics(
    systemId,
    true,
    0.1,
    0.01
)

setMetaballVelocity

Section titled “setMetaballVelocity”

Sets the velocity of a metaball.

Example
Section titled “Example”
gpu.setMetaballVelocity(
    systemId,
    ballId,
    2,
    -1
)

updateMetaballs

Section titled “updateMetaballs”

Advances the metaball simulation.

Call this every frame when using physics.

Example
Section titled “Example”
gpu.updateMetaballs(
    systemId,
    0.05
)