Introduce CanvasRenderingContext2D and WebGLRenderingContext

[ghost]

Feautre request: Introduce CanvasRenderingContext2D and WebGLRenderingContext constructors in Node.js. There are a few modules on npm trying to simulate them, but their performance and number of methods (and also number of issues) simply cannot be compared with, for example, Chrome's implementation.

Node.js doesn't have to display rendered image, just let users obtain rgb24 byte stream to use for further purposes. I tried to create a good implementation and publish it as npm module, but it was a huge failure.

What do you think about this idea? If you want new developers for this purpose, then I cannot help you. But I'm sure this will be a great step for Node.js.

[mscdex]

-1 These sorts of things are best left to userland.

[addaleax]

@6-8-axnw1bom81v5xa3nh48c It might be helpful if you could mention what difficulties you were running into when developing this as an npm module? Moving the work into Node wouldn’t get rid of any of these…

(Unless there’s anything in here that definitely can’t be done without support from inside Node, I’d agree with @mscdex, this should be done in userland…)

[ghost]

@addaleax Thanks for the response. Well, implementing WebGL is much harder than I thought. In order to create an useful, fast and efficient WebGL engine, one must create GLSL parser and compiler, code optimizer, translate the code into assemblies, use CUDA or other engine to embed the compiled code into GPU, implement efficient vector and matrix operations, multiplication, transposition, inverse, determinant, and also a lot of operations on vectors, dot and cross product, angle and so on.

Also, by creating GLSL parser, one must take care about syntax and type errors in the shader code, prevent compiling bad code, detect memory leaks, and moreover, optimize everything so that it works fast like in Chrome. "What difficulties you were running into when developing this?" - well, if it was easy, everyone would create its own engine for this purpose. Thats a lot of work and its definitely not easy.

As for 2D canvas context, it is not such a big problem. There are already some fast modules which (although not supporting all methods defined by the standard) allow users to render 2D graphics and obtain byte stream.

[addaleax]

@6-8-axnw1bom81v5xa3nh48c I don’t think any of that is going to be easier when being implemented inside of Node…

[Fishrock123]

I think you probably want a headless browser. Chrome supports running like that natively these days, you'll just have to find how to launch it without launching a window.

[ghost]

@Fishrock123 Thank you for suggestion. There are already headless browsers (like PhantomJS) and also it is easy to launch even Chrome in headless mode (at least on Windows). However, the problem is because there is no way to transfer the image data buffer to Node.js, except using WebSocket or XMLHttpRequest. Both ways are extremely slow for huge renderings, and therefore completely useless.

[TimothyGu]

@6-8-axnw1bom81v5xa3nh48c A quick Google search turns up headless-gl which uses ANGLE, so obviously not GPU-accelerated, but probably still faster than WebSocket etc.

Either way, this question is better suited for nodejs/help than here, which is used for issues in Node.js itself. Thus, closing this issue.