static void Main()
{
DriverType?driverType = AskForDriver();
if (!driverType.HasValue)
{
return;
}
IrrlichtDevice device = IrrlichtDevice.CreateDevice(driverType.Value, new Dimension2Di(640, 480));
if (device == null)
{
return;
}
device.OnEvent += new IrrlichtDevice.EventHandler(device_OnEvent);
VideoDriver driver = device.VideoDriver;
SceneManager scene = device.SceneManager;
scene.GUIEnvironment.AddStaticText("Press Space to hide occluder.", new Recti(10, 10, 200, 50));
// Create the node to be occluded. We create a sphere node with high poly count.
MeshSceneNode node = scene.AddSphereSceneNode(10, 64);
if (node != null)
{
node.Position = new Vector3Df(0, 0, 60);
node.SetMaterialTexture(0, driver.GetTexture("../../media/wall.bmp"));
node.SetMaterialFlag(MaterialFlag.Lighting, false);
}
// Now we create another node, the occluder. It's a simple plane.
SceneNode plane = scene.AddMeshSceneNode(
scene.AddHillPlaneMesh("plane", new Dimension2Df(10), new Dimension2Di(2)), // mesh
null, // parent
-1, // id
new Vector3Df(0, 0, 20), // position
new Vector3Df(270, 0, 0)); // rotation
if (plane != null)
{
plane.SetMaterialTexture(0, driver.GetTexture("../../media/t351sml.jpg"));
plane.SetMaterialFlag(MaterialFlag.Lighting, false);
plane.SetMaterialFlag(MaterialFlag.BackFaceCulling, true);
}
// Here we create the occlusion query. Because we don't have a plain mesh scene node
// (SceneNodeType.Mesh or SceneNodeType.AnimatedMesh), we pass the base geometry as well. Instead,
// we could also pass a simpler mesh or the bounding box. But we will use a time
// based method, where the occlusion query renders to the frame buffer and in case
// of success (occlusion), the mesh is not drawn for several frames.
driver.AddOcclusionQuery(node, node.Mesh);
// We have done everything, just a camera and draw it. We also write the
// current frames per second and the name of the driver to the caption of the
// window to examine the render speedup.
// We also store the time for measuring the time since the last occlusion query ran
// and store whether the node should be visible in the next frames.
scene.AddCameraSceneNode();
uint timeNow = device.Timer.Time;
bool nodeVisible = true;
while (device.Run())
{
plane.Visible = !IsKeyDown(KeyCode.Space);
driver.BeginScene(ClearBufferFlag.All, new Color(113, 113, 133));
// First, we draw the scene, possibly without the occluded element. This is necessary
// because we need the occluder to be drawn first. You can also use several scene
// managers to collect a number of possible occluders in a separately rendered scene.
node.Visible = nodeVisible;
scene.DrawAll();
scene.GUIEnvironment.DrawAll();
// Once in a while, here every 100 ms, we check the visibility. We run the queries,
// update the pixel value, and query the result. Since we already rendered the node
// we render the query invisible. The update is made blocking, as we need the result
// immediately. If you don't need the result immediately, e.g. because oyu have other
// things to render, you can call the update non-blocking. This gives the GPU more
// time to pass back the results without flushing the render pipeline.
// If the update was called non-blocking, the result from getOcclusionQueryResult is
// either the previous value, or 0xffffffff if no value has been generated at all, yet.
// The result is taken immediately as visibility flag for the node.
if (device.Timer.Time - timeNow > 100)
{
driver.RunAllOcclusionQueries(false);
driver.UpdateAllOcclusionQueries();
nodeVisible = driver.GetOcclusionQueryResult(node) > 0;
timeNow = device.Timer.Time;
}
driver.EndScene();
device.SetWindowCaption(String.Format(
"Occlusion Query Example - Irrlicht Engine [{0}] fps: {1} (primitives: {2})",
driver.Name, driver.FPS, driver.PrimitiveCountDrawn));
}
device.Drop();
}