Struct BrushContext 

pub struct BrushContext {
    pub value: Option<f32>,
    pub stroke: BrushStroke,
}

An object representing the state of a terrain brush being used from code. It has methods for starting, stopping, stamping, and smearing.

Each BrushContext requires some amount of heap allocation, so it may be preferable to reuse a BrushContext for multiple strokes when possible.

A single brush stroke can include multiple operations across multiple frames, but the terrain’s texture resources should not be replaced during a stroke because the BrushContext holds references the the texture resources that the terrain had when the stroke started, and any brush operations will be applied to those textures regardless of replacing the textures in the terrain.

Fields

value: Option<f32>

Parameter value for the brush. For flattening, this is the target height. For flattening, it starts as None and then is given a value based on the first stamp or smear.

stroke: BrushStroke

The pixel and brush data of the in-progress stroke.

Implementations

impl BrushContext

pub fn brush(&self) -> &Brush

The current brush. This is immutable access only, because the brush’s target may only be changed through BrushContext::start_stroke.

Mutable access to the brush’s other properties is available through BrushContext::shape, BrushContext::mode, BrushContext::hardness, and BrushContext::alpha.

pub fn shape(&mut self) -> &mut BrushShape

Mutable access to the brush’s shape. This allows the shape of the brush to change without starting a new stroke.

pub fn mode(&mut self) -> &mut BrushMode

Mutable access to the brush’s mode. This allows the mode of the brush to change without starting a new stroke.

pub fn hardness(&mut self) -> &mut f32

Mutable access to the brush’s hardness. This allows the hardness of the brush to change without starting a new stroke.

pub fn alpha(&mut self) -> &mut f32

Mutable access to the brush’s alpha. This allows the alpha of the brush to change without starting a new stroke.

pub fn start_stroke(&mut self, terrain: &Terrain, brush: Brush)

Modify the given BrushStroke so that it is using the given Brush and it is modifying the given terrain. The BrushContext will now hold references to the textures of this terrain for the target of the given brush, and so the stroke should not be used with other terrains until the stroke is finished.

• terrain: The terrain that this stroke will edit.
• brush: The Brush containing the brush shape and painting operation to perform.

pub fn stamp(&mut self, terrain: &Terrain, position: Vector3<f32>)

Modify the brushstroke to include a stamp of the brush at the given position. The location of the stamp relative to the textures is determined based on the global position of the terrain and the size of each terrain pixel.

• terrain: The terrain that will be used to translate the given world-space coordinates into texture-space coordinates. This should be the same terrain as was given to BrushContext::start_stroke.
• position: The position of the brush in world coordinates.

pub fn smear( &mut self, terrain: &Terrain, start: Vector3<f32>, end: Vector3<f32>, )

Modify the brushstroke to include a smear of the brush from start to end. The location of the smear relative to the textures is determined based on the global position of the terrain and the size of each terrain pixel.

• terrain: The terrain that will be used to translate the given world-space coordinates into texture-space coordinates. This should be the same terrain as was given to BrushContext::start_stroke.
• start: The start of the brush in world coordinates.
• end: The end of the brush in world coordinates.

pub fn flush(&mut self)

Update the terrain’s textures to include the latest pixel data without ending the stroke.

pub fn end_stroke(&mut self)

Update the terrain’s textures to include the latest data and clear this context of all pixel data to prepare for starting another stroke.

Trait Implementations

impl Default for BrushContext

fn default() -> BrushContext

Returns the “default value” for a type.