// reset our viewport after a window resize
func resizeWindow(width, height int) {
	// protect against a divide by zero
	if height == 0 {
		height = 1
	}

	// Setup our viewport
	gl.Viewport(0, 0, int(width), int(height))

	// change to the projection matrix and set our viewing volume.
	gl.MatrixMode(gl.PROJECTION)
	gl.LoadIdentity()

	// aspect ratio
	aspect := gl.GLdouble(gl.GLfloat(width) / gl.GLfloat(height))

	// Set our perspective.
	// This code is equivalent to using gluPerspective as in the original tutorial.
	var fov, near, far gl.GLdouble
	fov = 45.0
	near = 0.1
	far = 100.0
	top := gl.GLdouble(math.Tan(float64(fov*math.Pi/360.0))) * near
	bottom := -top
	left := aspect * bottom
	right := aspect * top
	gl.Frustum(float64(left), float64(right), float64(bottom), float64(top), float64(near), float64(far))

	// Make sure we're changing the model view and not the projection
	gl.MatrixMode(gl.MODELVIEW)

	// Reset the view
	gl.LoadIdentity()
}
Exemple #2
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// Handle the window being resized.
func reshape(width int, height int) {
	// Render into the entire window.
	gl.Viewport(0, 0, width, height)
	gl.MatrixMode(gl.PROJECTION)
	gl.LoadIdentity()

	// Configure the Frustrum so the front face of the rendering
	// volume fills the screen.

	w := float64(width)
	h := float64(height)
	depth := (w + h) / 2
	near := depth / 2.0
	right := w / 4.0
	top := h / 4.0
	far := 4 * depth
	gl.Frustum(-right, right, -top, top, near, far)

	gl.MatrixMode(gl.MODELVIEW)
	gl.LoadIdentity()

	// Center the rendering volume in the viewport.  Its origin
	// is at the far lower left corner.

	gl.Translated(-w/2, -h/2, -2*depth)
}
Exemple #3
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/* new window size or exposure */
func reshape(width int, height int) {

	h := float64(height) / float64(width)

	gl.Viewport(0, 0, width, height)
	gl.MatrixMode(gl.PROJECTION)
	gl.LoadIdentity()
	gl.Frustum(-1.0, 1.0, -h, h, 5.0, 60.0)
	gl.MatrixMode(gl.MODELVIEW)
	gl.LoadIdentity()
	gl.Translatef(0.0, 0.0, -40.0)
}
Exemple #4
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func (self *Viewport) Perspective(fovy, aspect, zNear, zFar float64) {
	gl.MatrixMode(gl.PROJECTION)
	gl.LoadIdentity()

	var xmin, xmax, ymin, ymax float64

	ymax = zNear * math.Tan(fovy*math.Pi/360.0)
	ymin = -ymax
	xmin = ymin * aspect
	xmax = ymax * aspect

	gl.Frustum(xmin, xmax, ymin, ymax, zNear, zFar)

	gl.MatrixMode(gl.MODELVIEW)
	gl.Hint(gl.PERSPECTIVE_CORRECTION_HINT, gl.NICEST)
	gl.DepthMask(true)
}
Exemple #5
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func initGl() {

	h := float64(height) / float64(width)

	gl.Viewport(0, 0, width, height)
	gl.MatrixMode(gl.PROJECTION)
	gl.LoadIdentity()
	gl.Frustum(-1.0, 1.0, -h, h, 5.0, 60.0)

	gl.MatrixMode(gl.MODELVIEW)
	gl.LoadIdentity()
	gl.Translatef(0.0, 0.0, -6.0)

	gl.EnableClientState(gl.VERTEX_ARRAY)
	gl.EnableClientState(gl.TEXTURE_COORD_ARRAY)
	gl.VertexPointer(3, 0, &vertices[0][0])
	gl.TexCoordPointer(2, 0, &texCoords[0][0])
}
Exemple #6
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func setup_opengl(width, height int) {
	ratio := float64(width) / float64(height)
	gl.ShadeModel(gl.SMOOTH)
	gl.CullFace(gl.BACK)
	gl.FrontFace(gl.CCW)
	gl.Enable(gl.CULL_FACE)
	gl.ClearColor(0, 0, 0, 0)
	gl.Viewport(0, 0, width, height)
	gl.MatrixMode(gl.PROJECTION)
	gl.LoadIdentity()

	gluPerspective := func(fovy, aspect, zNear, zFar float64) {
		top := math.Tan(fovy*0.5) * zNear
		bottom := -top
		left := aspect * bottom
		right := -left
		gl.Frustum(left, right, bottom, top, zNear, zFar)
	}
	gluPerspective(60.0, ratio, 1.0, 1024.0)
}