meshGenerated

Generated from the source

Data comes from entelechy serve + {"op":"kernels"} / {"op":"kernel"} · packages/mesh.entpkg/kernels/*.ent.

Category: Packages · Manifest: use "kernels/";

Brief

Triangle meshes as two rows, points and faces.

Description

Triangle meshes as two rows, points and faces: lattices that make the torus, the sphere and the plane, midpoint subdivision, and the surface where a field sampled on a lattice crosses a level. The faces are the raster package’s, so a mesh projected point by point is drawn as it is.

Layer: Graphics. Uses: parallel, raster.

use "mesh.entpkg";

Kernels

• kernels/iso.ent — The surface where a field sampled on a lattice (IsoLattice) crosses a level (dual contouring): a point in each cell it crosses, where the planes it crosses the cell’s edges on meet, so edges and corners stay sharp as far as the samples show them, and a quad across each lattice edge it crosses. Kernels: mesh.iso_crossed_cells@1, mesh.iso_slots@1, mesh.iso_points@1, mesh.iso_crossed_edges@1, mesh.iso_faces@1.
• kernels/lattice.ent — A lattice of points, columns a row and rows of them, and two faces to each of its cells. Kernels: mesh.lattice_faces@1, mesh.torus_points@1, mesh.sphere_points@1, mesh.plane_points@1.
• kernels/subdivision.ent — Midpoint subdivision, the step that changes a mesh’s topology. Kernels: mesh.split_points@1, mesh.split_faces@1.

Graph presets

• graphs/iso.esn — A field’s samples on a lattice in, the surface where they cross a level out, as points and faces.
• graphs/subdivision.esn — One level of midpoint subdivision.

Tests

tests/ holds scenes and their replays, run on every backend: iso.replay, lattice.replay. Every Kernel of the package is reached by one of them.

Used by the animation, culled, mesh, surface examples.

Kernels

Kernel	Mode	Brief
mesh.iso_crossed_cells@1	map	One flag a cell: whether the surface crosses it; none for a point on the lattice’s far sides, which has no cell.
mesh.iso_crossed_edges@1	map	One flag an edge of the lattice, edge 3 * point + axis from a point to the next along the axis: whether the surface crosses it with the four cells round it inside the lattice.
mesh.iso_faces@1	map	Two faces a crossed edge, from the crossed edges gathered: the quad of the four cells round it, turned to face out of the inside.
mesh.iso_points@1	map	The point of each crossed cell, where the planes of its edges’ crossings meet (iso_quadric_point), its normal the field’s slope there, its uv zero.
mesh.iso_slots@1	scatter into input 1 with max	Each crossed cell’s point among the points, from the crossed cells gathered (parallel.entpkg’s compaction), into a row of -1 a cell.
mesh.lattice_faces@1	map	The faces of a lattice.
mesh.plane_points@1	map	A flat sheet facing up, size across in x and z about the origin, an open lattice.
mesh.sphere_points@1	map	A sphere of radius about the origin, an open lattice: columns round its middle, rows from the pole below to the pole above.
mesh.split_faces@1	map	Each face’s three corners and its middle, over the split points.
mesh.split_points@1	map	The old points, then each face’s midpoints of its edges ab, bc and ca.
mesh.torus_points@1	map	A torus about up: its ring’s radius ring, its tube’s tube; columns go round the ring and rows round the tube. Wrapped both ways it has no seam in its points, and its coordinates jump from near 1 back to 0 across the last cells; open both ways, with a column and a row more, its seams lie twice over and its coordinates run 0 to 1 whole.

Methods

Function	Brief
iso_cells(l: IsoLattice) -> IVec3
iso_point_cell(l: IsoLattice, i: Int) -> IVec3
iso_point(l: IsoLattice, c: IVec3) -> Int
iso_corner(k: Int) -> IVec3
iso_axis(a: Int) -> IVec3
iso_along(c: IVec3, a: Int) -> Int
iso_place(l: IsoLattice, c: IVec3) -> Vec3
iso_inside(samples: Rows<Float>, l: IsoLattice, c: IVec3) -> Bool
iso_slope(samples: Rows<Float>, l: IsoLattice, c: IVec3) -> Vec3	The field’s slope at lattice point c: central differences, one-sided at the lattice’s sides.
iso_quadric_point(q: IsoQuadric, cell: Vec3, spacing: Float) -> Vec3
mesh_lattice_uv(i: Int, columns: Int, rows: Int, wrap_columns: Bool, wrap_rows: Bool) -> Vec2	Point i’s coordinates on the lattice, each 0 to 1.
mesh_lattice_face(t: Int, columns: Int, rows: Int, wrap_columns: Bool, wrap_rows: Bool) -> Face	Face t: of cell t / 2, the corner and its two neighbors along, then the corner, the far corner and the neighbor down.
mesh_midpoint(a: MeshPoint, b: MeshPoint) -> MeshPoint

Types and structs

Name	Syntax
IsoLattice	struct IsoLattice { points: IVec3; origin: Vec3; spacing: Float; level: Float; }
IsoQuadric	struct IsoQuadric { ax: Vec3; ay: Vec3; az: Vec3; b: Vec3; mean: Vec4; }
MeshPoint	struct MeshPoint { position: Vec3; normal: Vec3; uv: Vec2; }

Graph presets

Name	Interface	Description
iso	input samples: Rows<Float> param lattice: IsoLattice = IsoLattice { points: ivec3(2, 2, 2), origin: vec3(0.0, 0.0, 0.0), spacing: 1.0, level: 0.0 } output points <- points.result output faces <- faces.result output point_count <- cells.count output quad_count <- edges.count	The surface where a field crosses a level, as a mesh: samples on a lattice (IsoLattice: points along x, y and z, origin, spacing, level), x fastest; one point a cell the surface crosses and two faces an edge it crosses, closed where the surface stays inside the lattice. Place it with node shape: graph “mesh.entpkg/graphs/iso.esn” { samples <- field.result; lattice = IsoLattice { points: ivec3(64, 64, 64), origin: vec3(-1.0, -1.0, -1.0), spacing: 0.03175, level: 0.0 }; } and draw shape.points with shape.faces; shape.point_count and shape.quad_count say how many of each (faces, two a quad).
subdivision	input points: Rows<MeshPoint> input faces: Rows<Face> output points <- split.result output faces <- quartered.result

Kernel descriptions

mesh.iso_crossed_cells@1

One flag a cell: whether the surface crosses it; none for a point on the lattice’s far sides, which has no cell.

Mode	map
Requires	field.read, field.write
Inputs	samples: Rows<Float>
Params	lattice: IsoLattice = [[2, 2, 2], [0.0, 0.0, 0.0], 1.0, 0.0]
Outputs	result: Rows<Int>
Source	packages/mesh.entpkg/kernels/iso.ent

mesh.iso_crossed_edges@1

One flag an edge of the lattice, edge 3 * point + axis from a point to the next along the axis: whether the surface crosses it with the four cells round it inside the lattice.

Mode	map
Requires	field.read, field.write
Inputs	samples: Rows<Float>
Params	lattice: IsoLattice = [[2, 2, 2], [0.0, 0.0, 0.0], 1.0, 0.0]
Outputs	result: Rows<Int>
Source	packages/mesh.entpkg/kernels/iso.ent

mesh.iso_faces@1

Two faces a crossed edge, from the crossed edges gathered: the quad of the four cells round it, turned to face out of the inside.

Mode	map
Requires	field.read, field.write
Inputs	edges: Rows<Int>, slots: Rows<Int>, samples: Rows<Float>, total: Rows<Int>
Params	lattice: IsoLattice = [[2, 2, 2], [0.0, 0.0, 0.0], 1.0, 0.0]
Outputs	result: Rows<Face>
Source	packages/mesh.entpkg/kernels/iso.ent

mesh.iso_points@1

The point of each crossed cell, where the planes of its edges’ crossings meet (iso_quadric_point), its normal the field’s slope there, its uv zero.

Mode	map
Requires	field.read, field.write
Inputs	kept: Rows<Int>, samples: Rows<Float>, total: Rows<Int>
Params	lattice: IsoLattice = [[2, 2, 2], [0.0, 0.0, 0.0], 1.0, 0.0]
Outputs	result: Rows<MeshPoint>
Source	packages/mesh.entpkg/kernels/iso.ent

mesh.iso_slots@1

Each crossed cell’s point among the points, from the crossed cells gathered (parallel.entpkg’s compaction), into a row of -1 a cell.

Mode	scatter into input 1 with max
Requires	field.read, field.write
Inputs	kept: Rows<Int>, blank: Rows<Int>
Params	—
Outputs	result: Rows<Int>
Source	packages/mesh.entpkg/kernels/iso.ent

mesh.lattice_faces@1

The faces of a lattice.

Mode	map
Requires	field.write
Inputs	—
Params	columns: Int = 32, rows: Int = 16, wrap_columns: Bool = False, wrap_rows: Bool = False
Outputs	result: Rows<Face>
Source	packages/mesh.entpkg/kernels/lattice.ent

mesh.plane_points@1

A flat sheet facing up, size across in x and z about the origin, an open lattice.

Mode	map
Requires	field.write
Inputs	—
Params	size: Vec2 = [2.0, 2.0], columns: Int = 16, rows: Int = 16
Outputs	result: Rows<MeshPoint>
Source	packages/mesh.entpkg/kernels/lattice.ent

mesh.sphere_points@1

A sphere of radius about the origin, an open lattice: columns round its middle, rows from the pole below to the pole above.

Mode	map
Requires	field.write
Inputs	—
Params	radius: Float = 1.0, columns: Int = 33, rows: Int = 17
Outputs	result: Rows<MeshPoint>
Source	packages/mesh.entpkg/kernels/lattice.ent

mesh.split_faces@1

Each face’s three corners and its middle, over the split points.

Mode	map
Requires	field.read, field.write
Inputs	points: Rows<MeshPoint>, faces: Rows<Face>
Params	—
Outputs	result: Rows<Face>
Source	packages/mesh.entpkg/kernels/subdivision.ent

mesh.split_points@1

The old points, then each face’s midpoints of its edges ab, bc and ca.

Mode	map
Requires	field.read, field.write
Inputs	points: Rows<MeshPoint>, faces: Rows<Face>
Params	—
Outputs	result: Rows<MeshPoint>
Source	packages/mesh.entpkg/kernels/subdivision.ent

mesh.torus_points@1

A torus about up: its ring’s radius ring, its tube’s tube; columns go round the ring and rows round the tube. Wrapped both ways it has no seam in its points, and its coordinates jump from near 1 back to 0 across the last cells; open both ways, with a column and a row more, its seams lie twice over and its coordinates run 0 to 1 whole.

Mode	map
Requires	field.write
Inputs	—
Params	ring: Float = 1.0, tube: Float = 0.4, columns: Int = 48, rows: Int = 24, wrap_columns: Bool = True, wrap_rows: Bool = True
Outputs	result: Rows<MeshPoint>
Source	packages/mesh.entpkg/kernels/lattice.ent

Tests

iso.replay, lattice.replay