kiteplayer-audioviz/io.github.yuroyami.kiteplayer.audioviz.viz.mesh/TriangleMesh

TriangleMesh

class TriangleMesh(val maxVertices: Int = 4096, val maxIndices: Int = maxVertices * 6)

A batch of triangles with a colour at every corner, drawn in a single call.

Compose draws paths, and a tunnel drawn as paths reads as a wire frame because it is one. This fills the space between the lines instead. Each corner carries its own colour and the graphics card blends between them across the face, so lighting worked out once per corner comes out smooth over the whole surface. A few thousand triangles cost one call, where the same number of filled paths would cost a few thousand.

Build it once and reuse it: clear at the start of every frame, add corners with vertex, join them with triangle or quad, then hand it to drawMesh. Nothing is allocated after the first frame unless the number of triangles grows to a size the mesh has not drawn before.

Constructors

TriangleMesh

constructor(maxVertices: Int = 4096, maxIndices: Int = maxVertices * 6)

Properties

var indexCount: Int

val maxIndices: Int

val maxVertices: Int

var vertexCount: Int

Functions

clear

fun clear()

glow

fun TriangleMesh.glow(x: Float, y: Float, radius: Float, argb: Int, sides: Int = 6)

Adds a soft round spot: a fan of triangles in full colour at the middle and clear at the rim.

glyph

fun TriangleMesh.glyph(kind: Int, x: Float, y: Float, size: Float, turn: Float, argb: Int)

One of four small marks, turned by turn: 0 a cross, 1 a diamond, 2 a chevron, 3 a dash.

polygon

fun TriangleMesh.polygon(x: Float, y: Float, radius: Float, sides: Int, turn: Float, argb: Int, rim: Int = argb)

A filled regular polygon turned by turn radians: argb in the middle, rim at the corners.

quad

fun quad(a: Int, b: Int, c: Int, d: Int)

Two triangles covering four corners given in order round the edge.

ring

fun TriangleMesh.ring(x: Float, y: Float, radius: Float, thickness: Float, argb: Int, sides: Int = 24)

A ring thickness wide, in one colour, as a band of sides quads.

shard

fun TriangleMesh.shard(x: Float, y: Float, length: Float, turn: Float, argb: Int)

A thin sliver like a shard of glass, length long, turned by turn.

spark

fun TriangleMesh.spark(x: Float, y: Float, length: Float, width: Float, argb: Int)

A four pointed spark: two narrow diamonds crossed, bright in the middle and clear at the tips.

streak

fun TriangleMesh.streak(tailX: Float, tailY: Float, headX: Float, headY: Float, width: Float, argb: Int)

A streak from a clear tail to a bright head, width wide at the head.

strip

fun TriangleMesh.strip(xs: FloatArray, ys: FloatArray, count: Int, width: Float, argb: Int)

A wide line through the first count points of xs and ys.

triangle

fun triangle(a: Int, b: Int, c: Int)

Joins three corners. Quietly skipped when any of them does not exist or the mesh is full.

vertex

fun vertex(x: Float, y: Float, argb: Int): Int

Adds a corner and answers its number, or -1 when the mesh is full. argb is packed colour.