Esempio n. 1
0
func drawScene() {
	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)

	gl.MatrixMode(gl.MODELVIEW)
	gl.LoadIdentity()
	gl.Translatef(0, 0, -3.0)
	gl.Rotatef(rotationX, 1, 0, 0)
	gl.Rotatef(rotationY, 0, 1, 0)

	rotationX += 0.5
	rotationY += 0.5

	gl.BindTexture(gl.TEXTURE_2D, texture)

	gl.Color4f(1, 1, 1, 1)

	gl.Begin(gl.QUADS)

	gl.Normal3f(0, 0, 1)
	gl.TexCoord2f(0, 0)
	gl.Vertex3f(-1, -1, 1)
	gl.TexCoord2f(1, 0)
	gl.Vertex3f(1, -1, 1)
	gl.TexCoord2f(1, 1)
	gl.Vertex3f(1, 1, 1)
	gl.TexCoord2f(0, 1)
	gl.Vertex3f(-1, 1, 1)

	gl.Normal3f(0, 0, -1)
	gl.TexCoord2f(1, 0)
	gl.Vertex3f(-1, -1, -1)
	gl.TexCoord2f(1, 1)
	gl.Vertex3f(-1, 1, -1)
	gl.TexCoord2f(0, 1)
	gl.Vertex3f(1, 1, -1)
	gl.TexCoord2f(0, 0)
	gl.Vertex3f(1, -1, -1)

	gl.Normal3f(0, 1, 0)
	gl.TexCoord2f(0, 1)
	gl.Vertex3f(-1, 1, -1)
	gl.TexCoord2f(0, 0)
	gl.Vertex3f(-1, 1, 1)
	gl.TexCoord2f(1, 0)
	gl.Vertex3f(1, 1, 1)
	gl.TexCoord2f(1, 1)
	gl.Vertex3f(1, 1, -1)

	gl.Normal3f(0, -1, 0)
	gl.TexCoord2f(1, 1)
	gl.Vertex3f(-1, -1, -1)
	gl.TexCoord2f(0, 1)
	gl.Vertex3f(1, -1, -1)
	gl.TexCoord2f(0, 0)
	gl.Vertex3f(1, -1, 1)
	gl.TexCoord2f(1, 0)
	gl.Vertex3f(-1, -1, 1)

	gl.Normal3f(1, 0, 0)
	gl.TexCoord2f(1, 0)
	gl.Vertex3f(1, -1, -1)
	gl.TexCoord2f(1, 1)
	gl.Vertex3f(1, 1, -1)
	gl.TexCoord2f(0, 1)
	gl.Vertex3f(1, 1, 1)
	gl.TexCoord2f(0, 0)
	gl.Vertex3f(1, -1, 1)

	gl.Normal3f(-1, 0, 0)
	gl.TexCoord2f(0, 0)
	gl.Vertex3f(-1, -1, -1)
	gl.TexCoord2f(1, 0)
	gl.Vertex3f(-1, -1, 1)
	gl.TexCoord2f(1, 1)
	gl.Vertex3f(-1, 1, 1)
	gl.TexCoord2f(0, 1)
	gl.Vertex3f(-1, 1, -1)

	gl.End()
}
Esempio n. 2
0
func (ctx *DrawContext) drawSphere(p vector.V3, r float64, c colorful.Color) {
	/* TODO:
	   - decrease sphere detail if it's further away
	   - only draw spheres that would be visible inside the frustum:
	     - (no small spheres near the far plane)
	*/
	if ctx.cam.SphereInFrustum(p, r) == OUTSIDE {
		return
	}

	gl.Color3f(float32(c.R), float32(c.G), float32(c.B))

	gl.MatrixMode(gl.MODELVIEW)
	gl.PushMatrix()
	defer gl.PopMatrix()

	slices := int(math.Max(10, 5*math.Log(r+1)))

	gl.Translated(p.X, p.Y, p.Z)
	gl.Scaled(r, r, r)

	l, ok := uint32(0), false
	if ctx.wireframe {
		l, ok = ctx.spheresWireframe[slices]
	} else {
		l, ok = ctx.spheresSolid[slices]
	}

	if !ok {
		ctx.listId++ // XXX: atomic?
		l = ctx.listId
		gl.NewList(l, gl.COMPILE)
		for i := 0; i <= slices; i++ {
			lat0 := math.Pi * (-0.5 + float64(i-1)/float64(slices))
			z0 := math.Sin(lat0)
			zr0 := math.Cos(lat0)

			lat1 := math.Pi * (-0.5 + float64(i)/float64(slices))
			z1 := math.Sin(lat1)
			zr1 := math.Cos(lat1)

			if ctx.wireframe {
				gl.Begin(gl.LINES)
			} else {
				gl.Begin(gl.QUAD_STRIP)
			}
			for j := 0; j <= slices; j++ {
				lng := 2 * math.Pi * (float64(j-1) / float64(slices))
				x := math.Cos(lng)
				y := math.Sin(lng)

				gl.Normal3f(float32(x*zr0), float32(y*zr0), float32(z0))
				gl.Vertex3f(float32(x*zr0), float32(y*zr0), float32(z0))
				gl.Normal3f(float32(x*zr1), float32(y*zr1), float32(z1))
				gl.Vertex3f(float32(x*zr1), float32(y*zr1), float32(z1))
			}
			gl.End()
		}
		gl.EndList()
		if ctx.wireframe {
			ctx.spheresWireframe[slices] = l
		} else {
			ctx.spheresSolid[slices] = l
		}
	}

	gl.CallList(l)
}