func (pen *Pen) lineTo(p Point) {
gl.Enable(gl.BLEND)
gl.Enable(gl.POINT_SMOOTH)
gl.Enable(gl.LINE_SMOOTH)
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
gl.Color4f(0.0, 0.0, 0.0, 0.1)
gl.Begin(gl.LINES)
for _, s := range pen.points {
if s.x == 0 && s.y == 0 {
continue
}
if p.distanceTo(s) < 20.0 {
gl.Vertex2i(int(p.x), int(p.y))
gl.Vertex2i(int(s.x), int(s.y))
}
}
gl.End()
pen.n = (pen.n + 1) % len(pen.points)
pen.points[pen.n] = p
pen.moveTo(p)
}
func drawQuad(x, y, w, h int, u, v, u2, v2 float32) {
gl.Begin(gl.QUADS)
gl.TexCoord2f(float32(u), float32(v))
gl.Vertex2i(int(x), int(y))
gl.TexCoord2f(float32(u2), float32(v))
gl.Vertex2i(int(x+w), int(y))
gl.TexCoord2f(float32(u2), float32(v2))
gl.Vertex2i(int(x+w), int(y+h))
gl.TexCoord2f(float32(u), float32(v2))
gl.Vertex2i(int(x), int(y+h))
gl.End()
}
func drawSelection(p1, p2 Point) {
min, max := minMaxPoints(p1, p2)
gl.Color3ub(255, 0, 0)
gl.Begin(gl.LINES)
gl.Vertex2i(int(min.X), int(min.Y))
gl.Vertex2i(int(max.X), int(min.Y))
gl.Vertex2i(int(min.X), int(min.Y))
gl.Vertex2i(int(min.X), int(max.Y))
gl.Vertex2i(int(max.X), int(max.Y))
gl.Vertex2i(int(max.X), int(min.Y))
gl.Vertex2i(int(max.X), int(max.Y))
gl.Vertex2i(int(min.X), int(max.Y))
gl.End()
gl.Color3ub(255, 255, 255)
}
func gear(inner_radius, outer_radius, width float64, teeth int, tooth_depth float64) {
var i int
var r0, r1, r2 float64
var angle, da float64
var u, v, len float64
r0 = inner_radius
r1 = outer_radius - tooth_depth/2.0
r2 = outer_radius + tooth_depth/2.0
da = 2.0 * math.Pi / float64(teeth) / 4.0
gl.ShadeModel(gl.FLAT)
gl.Normal3d(0.0, 0.0, 1.0)
/* draw front face */
gl.Begin(gl.QUAD_STRIP)
for i = 0; i <= teeth; i++ {
angle = float64(i) * 2.0 * math.Pi / float64(teeth)
gl.Vertex3d(r0*math.Cos(angle), r0*math.Sin(angle), width*0.5)
gl.Vertex3d(r1*math.Cos(angle), r1*math.Sin(angle), width*0.5)
if i < teeth {
gl.Vertex3d(r0*math.Cos(angle), r0*math.Sin(angle), width*0.5)
gl.Vertex3d(r1*math.Cos(angle+3*da), r1*math.Sin(angle+3*da), width*0.5)
}
}
gl.End()
/* draw front sides of teeth */
gl.Begin(gl.QUADS)
da = 2.0 * math.Pi / float64(teeth) / 4.0
for i = 0; i < teeth; i++ {
angle = float64(i) * 2.0 * math.Pi / float64(teeth)
gl.Vertex3d(r1*math.Cos(angle), r1*math.Sin(angle), width*0.5)
gl.Vertex3d(r2*math.Cos(angle+da), r2*math.Sin(angle+da), width*0.5)
gl.Vertex3d(r2*math.Cos(angle+2*da), r2*math.Sin(angle+2*da), width*0.5)
gl.Vertex3d(r1*math.Cos(angle+3*da), r1*math.Sin(angle+3*da), width*0.5)
}
gl.End()
gl.Normal3d(0.0, 0.0, -1.0)
/* draw back face */
gl.Begin(gl.QUAD_STRIP)
for i = 0; i <= teeth; i++ {
angle = float64(i) * 2.0 * math.Pi / float64(teeth)
gl.Vertex3d(r1*math.Cos(angle), r1*math.Sin(angle), -width*0.5)
gl.Vertex3d(r0*math.Cos(angle), r0*math.Sin(angle), -width*0.5)
if i < teeth {
gl.Vertex3d(r1*math.Cos(angle+3*da), r1*math.Sin(angle+3*da), -width*0.5)
gl.Vertex3d(r0*math.Cos(angle), r0*math.Sin(angle), -width*0.5)
}
}
gl.End()
/* draw back sides of teeth */
gl.Begin(gl.QUADS)
da = 2.0 * math.Pi / float64(teeth) / 4.0
for i = 0; i < teeth; i++ {
angle = float64(i) * 2.0 * math.Pi / float64(teeth)
gl.Vertex3d(r1*math.Cos(angle+3*da), r1*math.Sin(angle+3*da), -width*0.5)
gl.Vertex3d(r2*math.Cos(angle+2*da), r2*math.Sin(angle+2*da), -width*0.5)
gl.Vertex3d(r2*math.Cos(angle+da), r2*math.Sin(angle+da), -width*0.5)
gl.Vertex3d(r1*math.Cos(angle), r1*math.Sin(angle), -width*0.5)
}
gl.End()
/* draw outward faces of teeth */
gl.Begin(gl.QUAD_STRIP)
for i = 0; i < teeth; i++ {
angle = float64(i) * 2.0 * math.Pi / float64(teeth)
gl.Vertex3d(r1*math.Cos(angle), r1*math.Sin(angle), width*0.5)
gl.Vertex3d(r1*math.Cos(angle), r1*math.Sin(angle), -width*0.5)
u = r2*math.Cos(angle+da) - r1*math.Cos(angle)
v = r2*math.Sin(angle+da) - r1*math.Sin(angle)
len = math.Sqrt(u*u + v*v)
u /= len
v /= len
gl.Normal3d(v, -u, 0.0)
gl.Vertex3d(r2*math.Cos(angle+da), r2*math.Sin(angle+da), width*0.5)
gl.Vertex3d(r2*math.Cos(angle+da), r2*math.Sin(angle+da), -width*0.5)
gl.Normal3d(math.Cos(angle), math.Sin(angle), 0.0)
gl.Vertex3d(r2*math.Cos(angle+2*da), r2*math.Sin(angle+2*da), width*0.5)
gl.Vertex3d(r2*math.Cos(angle+2*da), r2*math.Sin(angle+2*da), -width*0.5)
u = r1*math.Cos(angle+3*da) - r2*math.Cos(angle+2*da)
v = r1*math.Sin(angle+3*da) - r2*math.Sin(angle+2*da)
gl.Normal3d(v, -u, 0.0)
gl.Vertex3d(r1*math.Cos(angle+3*da), r1*math.Sin(angle+3*da), width*0.5)
gl.Vertex3d(r1*math.Cos(angle+3*da), r1*math.Sin(angle+3*da), -width*0.5)
gl.Normal3d(math.Cos(angle), math.Sin(angle), 0.0)
}
gl.Vertex3d(r1*math.Cos(0), r1*math.Sin(0), width*0.5)
gl.Vertex3d(r1*math.Cos(0), r1*math.Sin(0), -width*0.5)
gl.End()
gl.ShadeModel(gl.SMOOTH)
/* draw inside radius cylinder */
gl.Begin(gl.QUAD_STRIP)
for i = 0; i <= teeth; i++ {
angle = float64(i) * 2.0 * math.Pi / float64(teeth)
gl.Normal3d(-math.Cos(angle), -math.Sin(angle), 0.0)
gl.Vertex3d(r0*math.Cos(angle), r0*math.Sin(angle), -width*0.5)
gl.Vertex3d(r0*math.Cos(angle), r0*math.Sin(angle), width*0.5)
}
gl.End()
}