I have a SphereMesh (inherits from MeshGeneratorBase as part of the Petzold.Media3D.dll) in my WPF 3D Scene. I also have thousands of ScreenSpaceLines3D objects on that sphere. I want to ignore everything in my scene except the SphereMesh and find out the X-Y-Z coordinate of where my mouse ray intersects with the sphere only. Even if there is another object X between the sphere and the mouse, I still want to know where the mouse would hit the sphere, as if object X didn't exist.
I've tried the below code using HitTest, but as I add thousands/millions of other objects in my scene/world, it becomes extremely slow. And the object obstruction issue is another problem I can't resolve.
What do you recommend?
Current code:
Point mousePos = new Point(x, y);
PointHitTestParameters hitParams = new PointHitTestParameters(mousePos);
VisualTreeHelper.HitTest(
viewPort,null,
delegate(HitTestResult hr)
{
RayMeshGeometry3DHitTestResult rayHit = hr as RayMeshGeometry3DHitTestResult;
if(rayHit != null)
{
// Mouse hits something
Console.WriteLine("Point: " + rayHit.PointHit);
}
return HitTestResultBehavior.Continue;
}, hitParams);
Any help?
Thanks.
Related
There are other similar questions, but they deal with only screenshotting the displayed application. My application is transparent, so I need to take a screenshot of both the displayed window and the background behind it.
This function correctly screenshots the app on my main monitor, but when it goes to the other monitor, the screenshots are the wrong shape and are completely black. If the window is partly on the monitor, then it still works, but as soon as the other monitor takes control of the window, I get black screenshots. How do I get the screenshots to render correctly?
Here is my function:
public void SaveSnapshot2(int count)
{
string imageName = "image" + count.ToString() + ".jpeg";
string basePath = Path.GetFullPath(Environment.CurrentDirectory);
string folderPath = Path.Combine(basePath, "Snapshots");
string fullPath = Path.Combine(folderPath, imageName);
if (!Directory.Exists(folderPath))
{
Directory.CreateDirectory(folderPath);
}
System.Windows.Point relativeWindowPosition = App.Current.MainWindow.PointToScreen(new System.Windows.Point(0, 0));
System.Windows.Point relativeBottomRightWindowPosition = App.Current.MainWindow.PointToScreen(new System.Windows.Point(App.Current.MainWindow.Width, App.Current.MainWindow.Height));
System.Windows.Point actualWidthHeight = new System.Windows.Point((relativeBottomRightWindowPosition.X - relativeWindowPosition.X), (relativeBottomRightWindowPosition.Y - relativeWindowPosition.Y));
System.Drawing.Size convertedSize = new System.Drawing.Size((int)actualWidthHeight.X, (int)actualWidthHeight.Y);
Bitmap Screenshot = new Bitmap((int)actualWidthHeight.X, (int)actualWidthHeight.Y, PixelFormat.Format32bppArgb);
using (Graphics g = Graphics.FromImage(Screenshot))
{
// Crops the screenshot
// The relativePoint is where the top left corner of the image is. This is correct.
g.CopyFromScreen((int)relativeWindowPosition.X, (int)relativeWindowPosition.Y, 0, 0, convertedSize); // or (0, 0, 0, 0, Screenshot.Size) to get the whole bitmap image
}
try
{
Screenshot.Save(fullPath, ImageFormat.Jpeg);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message + ", the image did not save.");
}
Screenshot.Dispose();
}
Coming up with names for the points was difficult. I hope they are clear enough.
Does the coordinate system change when a window is on a separate monitor? Am I going about this the right way?
I guess you have not declared DPI awareness in the application manifest. It's a common pitfall when you have multiple monitors of different DPI. If have not, most methods and functions related to screen coordinates will return incorrect values and thus the calculation based on those values will be screwed up.
To solve this, add the application manifest which declares DPI awareness. See Setting the default DPI awareness for a process. PerMonitorV2 is the key for Per-Monitor DPI.
I have a SCNPlane that I created in the SceneKit editor and I want 1 side of the plane to have a certain image and the other side of the plane to have another image. How do I do that in the Scenekit editor
So far what I've tried to do is adding 2 materials to the plane. I tried adding 2 materials and unchecking double-sided but that doesn't work.
Any help would be appreciated!
Per the SCNPlane docs:
The surface is one-sided. Its surface normal vectors point in the positive z-axis direction of its local coordinate space, so it is only visible from that direction by default. To render both sides of a plane, ether set the isDoubleSided property of its material to true or create two plane geometries and orient them back to back.
That implies a plane has only one material — isDoubleSided is a property of a material, letting that one material render on both sides of a surface, but there's nothing you can do to one material to turn it into two.
If you want a flat surface with two materials, you can arrange two planes back to back as the doc suggests. Make them both children of a containing node and you can then use that to move them together. Or you could perhaps make an SCNBox that's very thin in one dimension.
Very easy to do in 2022.
It's very easy and common to do this, you just add the rear as a child.
To be clear the node (and the rear you add) should both use the single-sided shader.
Obviously, the rear you add points in the other direction!
Do note that they are indeed in "exactly the same place". Sometimes folks new to 3D mesh think the two meshes would need to be "a little apart", not so.
public var rear = SCNNode()
private var theRearPlane = SCNPlane()
private func addRear() {
addChildNode(rear)
rear.eulerAngles = SCNVector3(0, CGFloat.pi, 0)
theRearPlane. ... set width, height etc
theRearPlane.firstMaterial?.isDoubleSided = false
rear.geometry = theRearPlane
rear.geometry?.firstMaterial!.diffuse.contents = .. your rear image/etc
}
So ...
///Double-sided sprite
class SCNTwoSidedNode: SCNNode {
public var rear = SCNNode()
private var thePlane = SCNPlane()
override init() {
super.init()
thePlane. .. set size, etc
thePlane.firstMaterial?.isDoubleSided = false
thePlane.firstMaterial?.transparencyMode = .aOne
geometry = thePlane
addRear()
}
Consuming code can just refer to .rear , for example,
playerNode. ... the drawing of the Druid
playerNode.rear. ... Druid rules and abilities text
enemyNode. ... the drawing of the Mage
enemyNode.rear. ... Mage rules and abilities text
If you want to do this in the visual editor - very easy
It's trivial. Simply add the rear as a child. Rotate the child 180 degrees on Y.
It's that easy.
Make them both single-sided and put anything you want on the front and rear.
Simply move the main one (the front) normally and everything works.
I'm struggling with the best way of changing the center point of a 3D object (Model3DGroup) in WPF.
I've exported a model from SketchUp and everything is fine, but the centers got off position, causing me trouble in rotating the objects.
Now I need to make some rotations around each object own center and have no idea on how to do it...
Any suggestions would be appreciated.
Thanks
Using Jackson Pope suggestion, I used the code below to get the center point of an object:
var bounds = this.My3DObject.Bounds;
var x = bounds.X + (bounds.SizeX / 2);
var y = bounds.Y + (bounds.SizeY / 2);
var z = bounds.Z + (bounds.SizeZ / 2);
var centerPoint = new Point3D(x, y, z);
Meanwhile I'll try find a better solution to try and move all the points to the desired offset...
To rotate an object around it's centre you need to first translate it so that its centre is at the origin. Then rotate it (and then potentially translate it back to its original position).
Find the minimum and maximum extent of the object, calculate its centre = min + (max-min)/2. Translate by (-centreX, -centreY, -centreZ), rotate and then translate by (centreX, centreY, centreZ).
What's the best way to convert a WPF (resolution-independent) width and height to physical screen pixels?
I'm showing WPF content in a WinForms Form (via ElementHost) and trying to work out some sizing logic. I've got it working fine when the OS is running at the default 96 dpi. But it won't work when the OS is set to 120 dpi or some other resolution, because then a WPF element that reports its Width as 96 will actually be 120 pixels wide as far as WinForms is concerned.
I couldn't find any "pixels per inch" settings on System.Windows.SystemParameters. I'm sure I could use the WinForms equivalent (System.Windows.Forms.SystemInformation), but is there a better way to do this (read: a way using WPF APIs, rather than using WinForms APIs and manually doing the math)? What's the "best way" to convert WPF "pixels" to real screen pixels?
EDIT: I'm also looking to do this before the WPF control is shown on the screen. It looks like Visual.PointToScreen could be made to give me the right answer, but I can't use it, because the control isn't parented yet and I get InvalidOperationException "This Visual is not connected to a PresentationSource".
Transforming a known size to device pixels
If your visual element is already attached to a PresentationSource (for example, it is part of a window that is visible on screen), the transform is found this way:
var source = PresentationSource.FromVisual(element);
Matrix transformToDevice = source.CompositionTarget.TransformToDevice;
If not, use HwndSource to create a temporary hWnd:
Matrix transformToDevice;
using(var source = new HwndSource(new HwndSourceParameters()))
transformToDevice = source.CompositionTarget.TransformToDevice;
Note that this is less efficient than constructing using a hWnd of IntPtr.Zero but I consider it more reliable because the hWnd created by HwndSource will be attached to the same display device as an actual newly-created Window would. That way, if different display devices have different DPIs you are sure to get the right DPI value.
Once you have the transform, you can convert any size from a WPF size to a pixel size:
var pixelSize = (Size)transformToDevice.Transform((Vector)wpfSize);
Converting the pixel size to integers
If you want to convert the pixel size to integers, you can simply do:
int pixelWidth = (int)pixelSize.Width;
int pixelHeight = (int)pixelSize.Height;
but a more robust solution would be the one used by ElementHost:
int pixelWidth = (int)Math.Max(int.MinValue, Math.Min(int.MaxValue, pixelSize.Width));
int pixelHeight = (int)Math.Max(int.MinValue, Math.Min(int.MaxValue, pixelSize.Height));
Getting the desired size of a UIElement
To get the desired size of a UIElement you need to make sure it is measured. In some circumstances it will already be measured, either because:
You measured it already
You measured one of its ancestors, or
It is part of a PresentationSource (eg it is in a visible Window) and you are executing below DispatcherPriority.Render so you know measurement has already happened automatically.
If your visual element has not been measured yet, you should call Measure on the control or one of its ancestors as appropriate, passing in the available size (or new Size(double.PositivieInfinity, double.PositiveInfinity) if you want to size to content:
element.Measure(availableSize);
Once the measuring is done, all that is necessary is to use the matrix to transform the DesiredSize:
var pixelSize = (Size)transformToDevice.Transform((Vector)element.DesiredSize);
Putting it all together
Here is a simple method that shows how to get the pixel size of an element:
public Size GetElementPixelSize(UIElement element)
{
Matrix transformToDevice;
var source = PresentationSource.FromVisual(element);
if(source!=null)
transformToDevice = source.CompositionTarget.TransformToDevice;
else
using(var source = new HwndSource(new HwndSourceParameters()))
transformToDevice = source.CompositionTarget.TransformToDevice;
if(element.DesiredSize == new Size())
element.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
return (Size)transformToDevice.Transform((Vector)element.DesiredSize);
}
Note that in this code I call Measure only if no DesiredSize is present. This provides a convenient method to do everything but has several deficiencies:
It may be that the element's parent would have passed in a smaller availableSize
It is inefficient if the actual DesiredSize is zero (it is remeasured repeatedly)
It may mask bugs in a way that causes the application to fail due to unexpected timing (eg. the code being called at or above DispatchPriority.Render)
Because of these reasons, I would be inclined to omit the Measure call in GetElementPixelSize and just let the client do it.
Simple proportion between Screen.WorkingArea and SystemParameters.WorkArea:
private double PointsToPixels (double wpfPoints, LengthDirection direction)
{
if (direction == LengthDirection.Horizontal)
{
return wpfPoints * Screen.PrimaryScreen.WorkingArea.Width / SystemParameters.WorkArea.Width;
}
else
{
return wpfPoints * Screen.PrimaryScreen.WorkingArea.Height / SystemParameters.WorkArea.Height;
}
}
private double PixelsToPoints(int pixels, LengthDirection direction)
{
if (direction == LengthDirection.Horizontal)
{
return pixels * SystemParameters.WorkArea.Width / Screen.PrimaryScreen.WorkingArea.Width;
}
else
{
return pixels * SystemParameters.WorkArea.Height / Screen.PrimaryScreen.WorkingArea.Height;
}
}
public enum LengthDirection
{
Vertical, // |
Horizontal // ——
}
This works fine with multiple monitors as well.
I found a way to do it, but I don't like it much:
using (var graphics = Graphics.FromHwnd(IntPtr.Zero))
{
var pixelWidth = (int) (element.DesiredSize.Width * graphics.DpiX / 96.0);
var pixelHeight = (int) (element.DesiredSize.Height * graphics.DpiY / 96.0);
// ...
}
I don't like it because (a) it requires a reference to System.Drawing, rather than using WPF APIs; and (b) I have to do the math myself, which means I'm duplicating WPF's implementation details. In .NET 3.5, I have to truncate the result of the calculation to match what ElementHost does with AutoSize=true, but I don't know whether this will still be accurate in future versions of .NET.
This does seem to work, so I'm posting it in case it helps others. But if anyone has a better answer, please, post away.
Just did a quick lookup in the ObjectBrowser and found something quite interesting, you might want to check it out.
System.Windows.Form.AutoScaleMode, it has a property called DPI. Here's the docs, it might be what you are looking for :
public const
System.Windows.Forms.AutoScaleMode Dpi
= 2
Member of System.Windows.Forms.AutoScaleMode
Summary: Controls scale relative to
the display resolution. Common
resolutions are 96 and 120 DPI.
Apply that to your form, it should do the trick.
{enjoy}
Im trying to apply a material to my GeometryModel3D at runtime like so:
var model3D = ShardModelVisual.Content as GeometryModel3D;
var materialGroup = model3D.Material as MaterialGroup;
BitmapImage image;
ResourceLoader.TryLoadImage("pack://application:,,,/AnzSurface;component/path file/img.png", out image, ".png");
var iceBrush = new ImageBrush(image);
var grp = new TransformGroup();
grp.Children.Add(new ScaleTransform(0.25, 0.65, 0.5, 0.5));
grp.Children.Add(new TranslateTransform(0.0, 0.0));
iceBrush.Transform = grp;
var iceMat = new DiffuseMaterial(iceBrush);
materialGroup.Children.Add(iceMat);
Which all works fine, and the material gets added.
What I dont understand is how I can map the users click on the screen to the offsets that need to be applied to the TranslateTransform.
I.e. at the moment, x: -0.25 moves the material backwards along the X axis, but I have NO IDEA how to get that type of a coordinate from the users mouse click...
when I do:
e.MouseDevice.GetPosition(ShardsViewPort3D);
that gives me normal X/Y corrds of the mouse click...
Thanks for any help you can give!
It sounds like you want to slide the material around on your geometry when you click on it. Here's how:
Use hit testing to translate your X/Y coordinates from the mouse click into a RayMeshGeometry3DHitTestResult as described in my earlier answer. This will give you the MeshGeometry3D that was hit, the vertices of the triangle that was hit, and the relative position on that triangle.
Look up each vertex index (VertexIndex1, VertexIndex2, VertexIndex2) in the MeshGeometry3D.TextureCoordinates to get the texture coordinates. This will give you three (u,v) pairs as Point objects. Multiply each the (u,v) pairs by the corresponding weight from the hit test result (VertexWeight1, VertexWeight2, VertexWeight3) and add the pairs together, ie:
uMouse = u1 * VertexWeight1 + u2 * VertexWeight2 + u3 * VertexWeight3
vMouse = v1 * VertexWeight1 + v2 * VertexWeight2 + v3 * VertexWeight3
Now you have a point (uMouse, vMouse) that indicates where on your material your mouse was clicked.
If you want a particular point on your texture to move to exactly where the mouse was clicked, just subtract the (uMouse, vMouse) where the mouse was clicked from the (u,v) coordinate of the location in the material you want to appear under the mouse, and set this as your TranslateTransform. If you want to handle dragging, store the computed (uMouse,vMouse) where the drag started and the transform as of the drag start, then as dragging progresses compute the new transform as:
translate = (uMouse,vMouse) - (uMouseDragStart, vMouseDragStart) + origTranslate
In code you'll write this as Point additions. I spelled it out as (u,v) in this explanation because I thought it was easier to understand if I did so. In actuality the code to compute (uMouse, vMouse) will look more like this:
var uv1 = hit.MeshHit.TextureCoordinates[hit.VertexIndex1];
var uv2 = hit.MeshHit.TextureCoordinates[hit.VertexIndex2];
var uv3 = hit.MeshHit.TextureCoordinates[hit.VertexIndex3];
var uvMouse = new Vector(
uv1.X * hit.VertexWeight1 + uv2.X * hit.VertexWeight2 + uv3.X * hit.VertexWeight3)
uv1.Y * hit.VertexWeight1 + uv2.Y * hit.VertexWeight2 + uv3.Y * hit.VertexWeight3);
and the code to update the transform during a drag will look something like this:
...
var translate = translateAtDragStart + uvMouse - uvMouseAtDragStart;
... = new TranslateTransform(translate.X, translate.Y);
You'll have to adapt this to the exact situation.
Note that your HitTest callback may be called multiple times, starting at the closest mesh and moving back. It may even be called with 2D hits, for example if a 2D object is in front of your Viewport3D. So you'll want to check each hit to see if it is really what you want, for example during dragging you want to keep checking the position on the mesh being dragged even if it is no longer foremost. Return HitTestResultBehavior.Stop from you callback once you have acted on the mesh being dragged.