D3D11 MultisampleEnable and AntialiasedLineEnable affecting line rendering - graphics

Microsoft D3D11 documentation for D3D11_RASTERIZER_DESC structure writes:
The settings of the MultisampleEnable and AntialiasedLineEnable members apply only to multisample antialiasing (MSAA) render targets (that is, render targets with sample counts greater than 1).
Should I expect line rendering to be affected by those members only when I am rendering to a multisampled target and not when I am rendering on a "single sampled" one?
When drawing a Line Strip I found line rasterization to be affected by those settings:
What am I missing?

Related

GLTF vertex colors in three.js viewer are off

Heyo,
I've just stumbled upon this weird issue with my GLTF import: When loading the file in my three.js viewer, the colors looking different from the original file.
Compare McCudy's viewer:
GLTF file as seen in https://gltf-viewer.donmccurdy.com/
With my three.js viewer:
three.js viewer with ambient light brightness increased unhealthily
And again McCurdy's viewer but set to linear color encoding:
GLTF file as seen in https://gltf-viewer.donmccurdy.com/ with linear encoding
Looks familiar right?
I've already tried what three suggests: changing the color encoding of the renderer to sRGBEncoding but this problem is it doesn't change anything. Regardless of whether I use linear or sRGB encoding, the colors look the same. I checked the renderer and the outputEncoding is applied correctly.
Any idea's to why the setting does not seem to be applied or what else could be the source of the color change?
For information, I'm running a fairly old version of three.js (r97) which for various reasons I cannot update.
In three.js r112, the renderer.outputEncoding property was added, replacing the older renderer.gammaOutput property. In any earlier versions, the equivalent of renderer.outputEncoding = THREE.sRGBEncoding would be:
renderer.gammaOutput = true;
renderer.gammaFactor = 2.2;
If materials have already been rendered before these settings are configured on the renderer, you may also need to set material.needsUpdate = true to recompile them.

SVGPanZoom discards original viewBox

I am using SVGPanZoom to manage the zooming of an SVG image in my hybrid Android (for all intents and purposes the same behavior as in Chrome) app. While zooming works well I have found a strange issue. My original inline SVG element goes like this
<svg id='puzzle' viewBox='0 0 1600 770' preserveAspectRatio='none'
width='100vw' height='85.5vh' fill-rule='evenodd' clip-rule='evenodd'
stroke-linejoin='round' stroke-miterlimit='1.414'
xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://
www.w3.org/1999/xlink'>
Initially this SVG element is empty and gets populated programmatically from JavaScript at run time after which I initiate SVGPanZoom as follows
var panZoom = svgPanZoom('#puzzle',
{panEnabled:false,controlIconsEnabled:false,
zoomEnabled:true,dblClickZoomEnabled:true,onZoom:postZoom});
panZoom.refreshRate = 10;
panZoom.zoomScaleSensitivity = 0.02;
The problem I have run into is this - I want my SVG image to fill the available area, 100vw x 85.5vhcompletely to do which I instruct it via the preserveAspectRatio="none"attribute above along with the viewBox="0 0 1600 770" attribute. I have found that this works - so long as I don't use SVGPanZoom. As soon as I initiate panZoom thezoomBox`attribute gets stripped out and I end up with an image that does not quite behave in terms of its default stretching/filling behavior.
SVGPanZoom is widely used so I assume that this behavior is down to me not quite setting it up properly. Dipping into the code I have found SVGPanZoom creates a cacheViewBoxand then proceeds to remove the original zoomBox attribute.
Which is fine if after that zooming works and the original behavior of the application does not change which is not what I find. What am I doing wrong here?
I've also run into this issue recently. From my research, this is just how the library works. I chose to live with this limitation for now but I found a couple other libraries that may work the way you intend (I haven't tried them yet):
jquery.panzoom is a jquery library that provides this functionality and also has some nice features. I know many people try to avoid jquery but it's pretty small and may do what you want. It handles SVG but I don't know what it does with the viewBox attribute.
react-svg-pan-zoom is a react component which may be useful if you are working in react.
I've also tried the PanZoom library but this also suffers the same viewBox limitation.
A note for anyone running into this thread. In the end I abandoned SVGPanZoom and decided to eschew the route of using any pan/zoom library at all. At the same time I decided to completely stop using the SVG viewBox and handle all zooming/panning entirely on my own through SVG transforms. The core steps involved
Wrap the entire SVG contents in a group to make it easier to manage the transform. I use the id attribute gOuter for this group
Set an initial scale for the SVG to occupy the desired client rectangle. In my case I had an original viewBox of 0 0 1600 770 intended to occupy 100% of screen width and 85% of screen height. So my scaling was scaleX = 1600/window.innerWidth and scaleY = 770/)0.85*window.innerHeight).
Apply this initial transform to the wrapping outer group, gOuter.setAttribute('transform','0 0 scaleX,scaleY)
Now in order to zoom to a an object whose virtual top left hand coordinates in the original viewBox were Ox,Oy you would use the transform
gOuter.setAttribute('transform',
scale(scaleX,scaleY) translate(-Ox,-Oy) scale(2*scaleX,2*scaleY) translate(Ox,Oy))
to zoom in by a factor of x 2. The important things to understand here
In SVG transformations are applied right to left.
Here we are translating the zoom point to the top l.h.s. scaling and then translating it back to its original location.
The problem is that we also need to allow for the original level of zoom through the initial scaling so we tag that on as one last transform
This leaves you in complete control of the zooming process and as a fringe benefit the operation becomes considerably more smooth than when using a pan/zoom library.

Using vtkImageActor for adding mask to vtkImageViewer2

I am developing on an application based on VTK and GDCM for viewing medical (DICOM) images.
The application has three windows that respectively show XY, YZ and XZ orientations (axial, coronal and sagittal). This is similar to the 2D views here. I use vtkImageViewer2 for this. The voxel values of the DICOM images are passed on to an instance of vtkImageData. The instance of the vtkImageData is the passed on the to three instances of vtkImageViewer2 (let's use imageViewerXY, imageViewerYZ and imageViewerXZ). The orientation of each instance of vtkImageViewer2 is then set using SetSliceOrientationToXY(), SetSliceOrientationToYZ() and SetSliceOrientationToXZ(). Without the mask, I can see the slices, couple the windows and scroll through the images perfectly fine.
To add the mask so that it is shown in the three views, I use vtkImageActor. For the XY view, which is the default view, this works fine. I update the instance of vtkImageActor, which I call maskActorXY based on the mouse events of XY window as follows:
int extent[6];
imageViewerXY->GetImageActor->GetDisplayExtent(extent);
maskActorXY->SetDisplayExtent(extent);
maskActorXY->Update();
imageViewerXY->GetRenerer->Render();
Now, when I do the same for the other two windows so that I can see the 3D mask in the other two orientations, for example for the YZ orientation,
imageViewerYZ->GetImageActor->GetDisplayExtent(extent);
maskActorYZ->SetDisplayExtent(extent);
maskActorYZ->Update();
imageViewerYZ->GetRenerer->Render();
I get an error message that traces to vtkImageData and accessing pixel values outside of the extent set for the mask actor.
I have a limited familiarity with VTK, but looking at the source code of vtkImageViewer2 (see UpdateDisplayExtent() on line 341), I don't understand why pixel values out side of the specified display extent are requested from my instances of vtkImageActor that represent the mask.
I found a solution. Since I am not familiar with VTK, I may not be able to provide a clear explanation. All that I needed were the following two lines for each mask to force its mappers to face the camera:
maskActorYZ->GetMapper()->SetAtFocalPointOn();
maskActorYZ->GetMapper()->SliceFacesCameraOn();
(see [vtkImageMapper3D][1] class.)

WebGL: Text rendering and blend issue

Hy
I have a rendering issue with text in WebGL.
Here the pb:
The first rendering is crappy the second is OK.
The difference is my DOM (nothing related to the HTML DOM):
The difference between the view V2 and V3 is:
V2 is just a green rectangle (composed of 2 GL triangles) and contains a DOM child V4 which is a Text View (means a text, render into a Canvas then copy into a texture)
The blend is done by the GPU
V3 is TextView with a green background. The text is rendered into a Canvas then into a texture (like the V4). And a Shader fill the rectangle and takes the texture to generate the final view => no blend (actually done by the shader)
It should be a problem of blend and texture configuration. But I cannot find the right configuration.
Here my default configuration for the blend:
gl_ctx.disable (gl_ctx.DEPTH_TEST);
gl_ctx.enable (gl_ctx.BLEND);
gl_ctx.blendFunc (gl_ctx.SRC_ALPHA, gl_ctx.ONE_MINUS_SRC_ALPHA);
gl_ctx.clearDepth (1.0);
gl_ctx.clearColor (1, 1, 1, 1);
Thanks in advance for your help.
NOTE 1: A view (Vn) is the basic document object into my WebGL toolkit. It's called internally a Sprite, it's composed basically by 4 vertices, and a vertex and fragment shaders are associated to it, for the rendering purpose.
NOTE 2: If I use this blend configuration:
gl_ctx.blendFunc (gl_ctx.ONE, gl_ctx.ONE_MINUS_SRC_ALPHA);
The text rendering works well but the rest of rendering, specially images had incorrect alpha.
NOTE 3: sorry dont have enough reputation(!!!) to include image in my post :-(
Canvas 2D always uses pre-multiplied alpha so you pretty much have to use the second blendfunc. Can you set that blendfunc just when you render text?

Adding SVG overlay to nokia HERE map

I'm working with nokia HERE maps and I want to add an additional layer of visualization graphics on top of a map. Since the possibilities to interact, manipulate and customize the graphics created by the HERE api are limited, I would like to work with d3.js/SVG for my visualizations.
My straight forward and obvious solution would have been to just add an absolute positioned SVG element on top of the map and giving it the same dimensions. But of course that takes every possibility to interact with the map. Is there any solution to add an overlay to the map which allows me to put SVG on it while maintaining the full interactivity (panning, zooming, clicking) of the map? Also it should be possible to interact with the SVG.
I know that there is a possibility to add a custom overlay of tiles provided by a tile server to HERE maps but that's not really what I'm looking for. I'm looking for something like the solution google has to offer to this problem. A set of custom layers which are always in sync with the corresponding map and have their own initialize, draw and remove methods. Is there something similar for HERE maps?
I think you are after the nokia.maps.map.provider.CanvasProvider class. This class provides a ground overlay bound to a specific area which offers a draw() method. The attach() method is the equivalent of your intialize I think, and you can refresh the overlay using update().
Depending upon your use case, I've also found the following techniques useful regarding SVG, Images and HERE Maps:
For an SVG marker which is anchored to a point and doesn't resize
use: SVG Markers
Alternatively override the Marker class and write using the low
level graphics commands to add flexibility to the rendering of a
marker anchored to a point. Like this: Defaced Marker
To add an image bound to a specific area use the ImageProvider class
To add a series of tiled images from a TMS (Tile Map Service) use the ImgTileProvider class
Alternatively if the [zoom][col][row] is useful to you and you
want to write SVG based stuff yourself try something like this example - which combines
SVG with 256x256 pixel markers.
Note that the HERE Maps API for JavaScript only supports SVG Tiny.
A class like the old nokia.maps.map.provider.CanvasProvider isn't even available on the new v3 API from Here.
Your best bet is on Leaflet using custom providers loading Here map tiles. Then you just load this Custom Overlay class and you're all set to draw D3, WebGL, whatever you need. Leaflet only loads the tiles from the providers and exposes some simple APIs. You will not have to deal with any of the providers' APIs.
Just don't forget to add your app_id and app_code to the provider class.

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