Struct SpanGouraud 

pub struct SpanGouraud<C: Clone> { /* private fields */ }

Gouraud shading base class.

Stores a triangle with per-vertex colors. Implements VertexSource to feed the (possibly dilated) triangle outline to the rasterizer.

Dilation produces a 6-vertex beveled polygon for numerical stability, while the color interpolation coordinates use miter joins calculated via calc_intersection.

Port of C++ span_gouraud<ColorT>.

Implementations

impl<C: Clone + Default> SpanGouraud<C>

pub fn new() -> Self

pub fn new_with_triangle( c1: C, c2: C, c3: C, x1: f64, y1: f64, x2: f64, y2: f64, x3: f64, y3: f64, d: f64, ) -> Self

Construct with colors and triangle geometry.

pub fn colors(&mut self, c1: C, c2: C, c3: C)

Set the vertex colors.

pub fn triangle( &mut self, x1: f64, y1: f64, x2: f64, y2: f64, x3: f64, y3: f64, d: f64, )

Set the triangle geometry and optionally dilate it.

When d != 0, the triangle is dilated to form a 6-vertex beveled polygon for numerical stability. The color interpolation coordinates are recalculated using miter-join intersections.

pub fn arrange_vertices(&self) -> [CoordType<C>; 3]

Sort vertices by Y coordinate (top to bottom).

Returns an array of three CoordType sorted so that result[0].y <= result[1].y <= result[2].y.

Trait Implementations

impl<C: Clone + Default> Default for SpanGouraud<C>

fn default() -> Self

Returns the “default value” for a type.

impl<C: Clone + Default> VertexSource for SpanGouraud<C>

fn rewind(&mut self, _path_id: u32)

Reset the vertex source to the beginning of the given path. path_id selects which sub-path to iterate (0 for the first/only path).

fn vertex(&mut self, x: &mut f64, y: &mut f64) -> u32

Return the next vertex. Writes coordinates to x and y, returns a path command. Returns PATH_CMD_STOP when iteration is complete.