Exemple #1
0
// 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)
}
Exemple #2
0
// Line draws a line between two points. It's 1 pixel thick.
func (w *Window) Line(v1, v2 *geom.Vec2, r, g, b byte) {
	// Always draw from left to right (x1 <= x2)
	if v1[0] > v2[0] {
		v1, v2 = v2, v1
	}
	dx := v2[0] - v1[0]
	dy := v2[1] - v1[1]
	var steps int
	if tmath.Absi(dx) > tmath.Absi(dy) {
		steps = dx
	} else {
		steps = tmath.Absi(dy)
	}
	xinc := float64(dx) / float64(steps)
	yinc := float64(dy) / float64(steps)
	x := float64(v1[0])
	y := float64(v1[1])
	for s := 0; s <= steps; s++ {
		w.Setxy(tmath.Round(x), tmath.Round(y), r, g, b)
		x += xinc
		y += yinc
	}
}
Exemple #3
0
// DrawLine draws a 1 pixel thick line between the (x1,y1) and (x2,y2) with the
// given color.
func (img *Image) DrawLine(x1, y1, x2, y2 int, c color.Color) {
	r := img.Rgba
	// Always draw from left to right (x1 <= x2)
	if x1 > x2 {
		x1, y1, x2, y2 = x2, y2, x1, y1
	}
	dx := x2 - x1
	dy := y2 - y1
	var steps int
	if tmath.Absi(dx) > tmath.Absi(dy) {
		steps = tmath.Absi(dx)
	} else {
		steps = tmath.Absi(dy)
	}
	xinc := float64(dx) / float64(steps)
	yinc := float64(dy) / float64(steps)
	x := float64(x1)
	y := float64(y1)
	for s := 0; s <= steps; s++ {
		r.Set(tmath.Round(x), tmath.Round(y), c)
		x += xinc
		y += yinc
	}
}
Exemple #4
0
// Transf transforms a 3D triangle with the given transformation matrix and
// returns a 2D triangle.
func (t *Tri4) Transf(m *geom.Mat4) *Tri2 {
	p1 := m.Transf(&t[0])
	x1 := tmath.Round(p1[0] / p1[3])
	y1 := tmath.Round(p1[1] / p1[3])
	p2 := m.Transf(&t[1])
	x2 := tmath.Round(p2[0] / p2[3])
	y2 := tmath.Round(p2[1] / p2[3])
	p3 := m.Transf(&t[2])
	x3 := tmath.Round(p3[0] / p3[3])
	y3 := tmath.Round(p3[1] / p3[3])
	return NewTri2(x1, y1, x2, y2, x3, y3)
}