func drawSquare(x, y, length float64) {
x2 := x + length
y2 := y + length
gl.Begin(gl.QUADS)
gl.Color3d(0.75, 0.35, 0.35)
gl.Vertex2d(x, y)
gl.Vertex2d(x2, y)
gl.Vertex2d(x2, y2)
gl.Vertex2d(x, y2)
gl.End()
}
// GlDraw draws the creature to the OpenGL screen.
func (me *Creature) GlDraw() {
// Draw the creature's body, which is just a circle.
gl.Color3d(me.Red(), me.Green(), me.Blue())
drawCircle(me.X(), me.Y(), me.R())
// Draw circles for the creature's eyes.
// (This is so we can tell what direction the creature is facing.)
//
// We'll make the eye size 7% of the total radius.
// We'll also put the eyes
rr := float64(0.07) * me.R()
//@TODO: Should speed this up by pre-computing all these cos() and sin() calculations and storing in a lookup table.
xx := me.X() + ((float64(0.8) * me.R()) * math.Cos(me.θ()-0.4))
yy := me.Y() + ((float64(0.8) * me.R()) * math.Sin(me.θ()-0.4))
gl.Color3d(0, 0, 0)
drawCircle(xx, yy, rr)
//@TODO: Should speed this up by pre-computing all these cos() and sin() calculations and storing in a lookup table.
xx = me.X() + ((float64(0.8) * me.R()) * math.Cos(me.θ()+0.4))
yy = me.Y() + ((float64(0.8) * me.R()) * math.Sin(me.θ()+0.4))
gl.Color3d(0, 0, 0)
drawCircle(xx, yy, rr)
// Draw creature's thrusters.
rr = float64(0.25) * me.R()
//@TODO: Should speed this up by pre-computing all these cos() and sin() calculations and storing in a lookup table.
xx = me.X() + ((float64(0.6) * me.R()) * math.Cos(me.θ()-2.4))
yy = me.Y() + ((float64(0.6) * me.R()) * math.Sin(me.θ()-2.4))
gl.Color3d(0, 0, 0)
drawCircle(xx, yy, rr)
//@TODO: Should speed this up by pre-computing all these cos() and sin() calculations and storing in a lookup table.
xx = me.X() + ((float64(0.6) * me.R()) * math.Cos(me.θ()+2.4))
yy = me.Y() + ((float64(0.6) * me.R()) * math.Sin(me.θ()+2.4))
gl.Color3d(0, 0, 0)
drawCircle(xx, yy, rr)
// Draw the creature's name.
xx = me.X() - me.R() - 10
yy = me.Y() - me.R() - 10
drawString(xx, yy, me.name)
// Draw the creature's energy.
xx = me.X() + me.R()
yy = me.Y() - me.R() - 10
s := fmt.Sprintf("energy: %v", me.E())
drawString(xx, yy, s)
// Draw the creature's x position.
xx = me.X() + me.R()
yy = me.Y() - me.R() + 30
s = fmt.Sprintf("x: %v", me.X())
drawString(xx, yy, s)
// Draw the creature's y position.
xx = me.X() + me.R()
yy = me.Y() - me.R() + 45
s = fmt.Sprintf("y: %v", me.Y())
drawString(xx, yy, s)
// Draw the creature's x speed.
xx = me.X() + me.R()
yy = me.Y() - me.R() + 60
s = fmt.Sprintf("dx: %v", me.Dx())
drawString(xx, yy, s)
// Draw the creature's y speed.
xx = me.X() + me.R()
yy = me.Y() - me.R() + 75
s = fmt.Sprintf("dy: %v", me.Dy())
drawString(xx, yy, s)
// Draw the creature's orientation.
xx = me.X() + me.R()
yy = me.Y() - me.R() + 90
s = fmt.Sprintf("θ: %v degrees", 360*me.θ()/(2*math.Pi))
drawString(xx, yy, s)
}