striped-cube.go

struped-cube.go

package main

import "github.com/fogleman/ln/ln"

type StripedCube struct {
	ln.Cube
	Stripes int
}

func (c *StripedCube) Paths() ln.Paths {
	var paths ln.Paths
	x1, y1, z1 := c.Min.X, c.Min.Y, c.Min.Z
	x2, y2, z2 := c.Max.X, c.Max.Y, c.Max.Z
	for i := 0; i <= c.Stripes; i++ {
		p := float64(i) / float64(c.Stripes)
		x := x1 + (x2-x1)*p
		y := y1 + (y2-y1)*p
		paths = append(paths, ln.Path{{x, y1, z1}, {x, y1, z2}})
		paths = append(paths, ln.Path{{x, y2, z1}, {x, y2, z2}})
		paths = append(paths, ln.Path{{x1, y, z1}, {x1, y, z2}})
		paths = append(paths, ln.Path{{x2, y, z1}, {x2, y, z2}})
	}
	return paths
}

func main() {
	// create a scene and add a single cube
	scene := ln.Scene{}
  cube := ln.NewCube(ln.Vector{-1, -1, -1}, ln.Vector{1, 1, 1})
	scene.Add(StripedCube(cube, 8))

	// define camera parameters
	eye := ln.Vector{4, 3, 2}    // camera position
	center := ln.Vector{0, 0, 0} // camera looks at
	up := ln.Vector{0, 0, 1}     // up direction

	// define rendering parameters
	width := 1024.0  // rendered width
	height := 1024.0 // rendered height
	fovy := 50.0     // vertical field of view, degrees
	znear := 0.1     // near z plane
	zfar := 10.0     // far z plane
	step := 0.01     // how finely to chop the paths for visibility testing

	// compute 2D paths that depict the 3D scene
	paths := scene.Render(eye, center, up, width, height, fovy, znear, zfar, step)

	// render the paths in an image
	paths.WriteToPNG("out.png", width, height)

	// save the paths as an svg
	paths.WriteToSVG("out.svg", width, height)
}