// NewTri4 returns a new triangle with points (x1,y1,z1), (x2,y2,z2) and
// (x3,y3,z3).
func NewTri4(x1, y1, z1, x2, y2, z2, x3, y3, z3 float64) *Tri4 {
return &Tri4{
*geom.NewVec4(x1, y1, z1),
*geom.NewVec4(x2, y2, z2),
*geom.NewVec4(x3, y3, z3),
}
}
// main creates a new scene with a camera and 3 vectors, renders the scene,
// draws the result to an image and encodes the image as PNG into a file.
// Optionally specify the filename.
func main() {
var filename = flag.String("file", "triangle.png", "Filename to store image")
flag.Parse()
cam := render.NewDefCam()
v1 := geom.NewVec4(-1, -1, -3)
v2 := geom.NewVec4(0, 1, -5)
v3 := geom.NewVec4(1, -1, -3)
t := cam.PerspTransf(500, 500)
w1 := t.Transf(v1)
w1.Norm()
w2 := t.Transf(v2)
w2.Norm()
w3 := t.Transf(v3)
w3.Norm()
x1 := tmath.Round(w1[0])
y1 := tmath.Round(w1[1])
x2 := tmath.Round(w2[0])
y2 := tmath.Round(w2[1])
x3 := tmath.Round(w3[0])
y3 := tmath.Round(w3[1])
img := image.NewImage(500, 500)
col := color.RGBA{255, 255, 0, 255}
img.DrawDot(x1, y1, col)
img.DrawDot(x2, y2, col)
img.DrawDot(x3, y3, col)
img.DrawLine(x1, y1, x2, y2, col)
img.DrawLine(x2, y2, x3, y3, col)
img.DrawLine(x3, y3, x1, y1, col)
file, err := os.Create(*filename)
if err != nil {
panic(err)
}
defer file.Close()
img.WritePng(file)
}