I m creating a THREE.js (latest version, r71) app, and sometimes I need to manually delete the 3D scene to display classic 2D content. So, what I do is clearing all variables like scene or renderer, and killing the WebGL context using renderer.forceContextLoss()
This method works fine on Firefox or Chrome, but it is not supported on Interner Explorer or Microsoft Edge, which cause multiple lags on my web page. I can't find a workaround to do this properly as I do in Firefox or Chrome.
If someone has a tip, feel free to tell me :)
Thanks
Try using two canvas tags and put one over the other as suggested here,
put them in a parent div tag then use the following css.
position:absolute;
left:0px;
top:0px;
EDIT:
In response to your comment, allow me to clarify my understanding.
You want to draw 2d and 3d.
You are resetting the webGL context.
You can't have 2 contexts to the same canvas simultaneously and I assume you want to use a a different context for your 2d content.
If this assumption is correct:
I am suggesting that you have 2 canvases and contexts simultaneously, one with your webGL context and 3d content, and another with the context you want to use for 2d content. Then you overlay these canvases by using absolute position, such that it looks like there is one canvas.
This means you never have to reload assets to switch contexts, just make sure you so the above canvas is transparent.
Also if you wrap the canvas in a div tag, it will not be at the top left of the page.
But If my assumption is wrong:
perhaps you don't want to use another context and just wish to clear the screen, in which case you should not call forceContextLoss()
If you wish to continue to use the webGL context, but clear the screen you should use clear()
Related
I'm playing about with three.js and webGL with an attempt to get html objects overlaid on a webGL model.
I intend to use three.js object loaders to render a 3D model, where I can then allow users to overlay HTML DOM objects in 3D space via a custom UI.
I've mainly been using the various different examples in the three.js docs (https://threejs.org/examples/ and https://codepen.io/AdamEDGE/pen/RRjEwz).
In order to allow the user to move the overlaid HTML objects via the UI, I've added the transform controls (https://threejs.org/examples/misc_controls_transform.html).
Things seemed to be going relatively well up to this point, but now I see that the controls are not hoverable or clickable to move the element.
I suspect I'm either missing code or an issue with the camera not aligning correctly, but I'm very new to this so I'm guessing.
I have also experimented with Jerome Etienne's blending tutorials, but on testing that caused other issues and I think may not be worth the trouble for what I'm going for (http://learningthreejs.com/blog/2013/04/30/closing-the-gap-between-html-and-webgl/index.html).
I have created an example that shows the problem (click on an object and the controls should show).
Its a simple webGL torus with two HTML images overlaid and mapped to a Mesh so I can link the controls to the HTML elements which are on a different scene.
https://jsfiddle.net/mattscotty/h5wuq86y/
control = new THREE.TransformControls(camera, glRenderer.domElement);
control.addEventListener('change', render);
The controls show on all the correct places when clicked as expected and I can use the keyboard to change the transform type (again see https://threejs.org/examples/misc_controls_transform.html for how it should work).
As I can't click or hover, I can't hook up to the relevant events.
I'm brand new to this and I'm quite sure I'm missing something obvious, so any help is appreciated.
I am upgrading the UI of my program (from the old Unity UI system to the new one), but it seems like I cannot work with screen-space canvas (either camera or overlay canvases). Objects in world-space canvases work fine. With screen-space GameObjects show in my "Game" preview-screen in the editor, so I am a bit confused as to what the problem may be. To be clear: objects show in the "Game" screen, but not when I press the "play" button.
I attach a composite screenshot with information about one of the objects, the canvases and the camera.
I think I now understand what the problem is. Apparently screen-space canvases (either overlay or camera) can ONLY work with UI-specific game objects. I still do not know why other sorts of elements can be added as children of these canvases (and specially why they correctly show in the Game-preview screen!)
Even if I am missing something deeper here, using elements from the UI folder works where others don't. I thought perhaps someone could find that useful.
I am using Unity 5 and I started to make a menu scene. When I made the canvas, all of values under the Rect Transform component are locked and it says "some values driven by Canvas." The only thing I can change is the z position when using the gizmo in the editor. I can't reset the position or anything. Why is this happening?
This means that the canvas's canvas component has it's render mode set to Screen space - overlay. This forces it to be the size of the screen. Change it to World Space and it will allow you to resize it and move it around.
Changing the Render mode is not an ideal solution; neither is Overlay mode the reason why this is happening at all. World Space is just a render mode that changes the way your whole UI behaves and would mean a whole different set up and a whole lot more work just to get a child UI object to move independently.
Here is the description of what World Space is for from the Unity site:
In this render mode, the Canvas will behave as any other object in the
scene. The size of the Canvas can be set manually using its Rect
Transform, and UI elements will render in front of or behind other
objects in the scene based on 3D placement. This is useful for UIs
that are meant to be a part of the world. This is also known as a
“diegetic interface”.
The Rect Transform usually gets locked because it is a child of another Canvas Object which controls its Transforms. The way to fix this is to overwrite it by adding a “Layout Element” component to it. From there you can configure it to work the way you like and it can have transforms independent of the Parent UI Object.
For full details, see this Unity support page: https://support.unity3d.com/hc/en-us/articles/115000179163-How-to-overwrite-Width-and-Height-values-that-are-driven-by-a-Layout-Group-in-runtime-
Canvas is depend on game tab in your window panel.
Adjust panel by use of close tab or resize panel or doc game panel.
It will help you make default 800 X 600 canvas.
I have been working on getting this seat mapping chart for a while and have created a few iterations, and the problem I keep finding is when I get to IE8 the panning for this is way to slow and delayed.
What I have at this point to cut down on load time is created a png to replace my "strokes" since I assume ie8 wanted to re-render each time I dragged the map.
I also added controls hoping to force IE8 users this option, but still there is a delay in the pan, and if I can have users with IE8 (and ie7 if possible) still drag/pan without the controls and the respond time a little faster that would be great.
Here is my current JSFiddle
I am still a little green with JS so if you have any suggestions it would be much appreciated. (PS Chrome frame is awesome but is not a option for me)
Update
I have removed the original dragging function and replaced the code using jqueryui's draggable function. Martin had suggested to just drag the div, and not the Raphael elements. Doing so lets this thing fly in ie6-8 which is great, but then came my concern about scaling. What I was seeing before on zoom my paper element WxH would stay the same ratio, cutting off my drawing when it zoomed in. After digging through the Raphael documentation I came across paper.setSize. setSize was exactly what I needed to allow this project to move and groove in ie6-8 and pretty much conquer all browsers in its path.
So in short, using jqueryui's draggable and paper.setSize has cured my cross browser zoom n' pan blues.
From what can be seen in the Fiddle, you are triggering a new rendering of the image by calling .translate() inside of a mousemove event handler:
mapContainer.translate(currentMapPosX, currentMapPosY);
rsrGroupies.translate(currentMapPosX, currentMapPosY);
This approach is toxic for performance in all browsers, let alone IE8. When dealing with VML in IE8 you should consider that each and every DOM change inside the image will result in the image being rendered again. Doing that while panning will always be painfully slow.
I see that you are already using jQuery in your Fiddle. If you want to increase performance of your panning, you should consider doing the following:
Render the image in Raphaël exactly once for the current zoom level. Do not attempt to change transformations in your VML/SVG image at any point in time while panning.
With the mousemove implementation of panning you already have, move or scroll the HTML container that holds your VML/SVG image instead. Imagine a <div> with overflow: hidden and simply move the image inside relatively, or scroll to the appropriate position.
This will require some adjustment of your coordinate calculations, but it will improve your performance in all browsers.
I'm setting up an experimental html5 website using canvas.
I am drawing 3 circles all next to each other and all I want to know is how to be able to select them.
I'd like them to become links, in a way. Not tags, since everything's gonna be created using javascript.
Something like kinetic JS : http://www.kineticjs.com/, but without the extra library.
I have found some scripts that are using ghost canvas and contexts, but the examples are for dragging and stuff. I only want to be able to select my shape and execute some code.
Thank you!
I am thinking you might want to look into the IsPointInPath() method. It will help you figure out whether or not the mouse clicked on your canvas object.
See Detect mouseover of certain points within an HTML canvas?
if you are talented in xml i suggest you to use canvas + SVG (http://www.w3schools.com/svg/)
And follow this simple example.
http://jsvectoreditor.googlecode.com/svn/trunk/index.html
regarding to SVG and Canvas , the differences are obvious, as you can load bitmaps in SVG, and you can draw lines using the canvas API. However, creating the image may be easier using one technology over the other, depending on whether your graphic is mainly line-based or more image-like.