OrthographicSSRPass (screen space reflection)

[gonnavis]

Demo Demo2
Inspired by Blender EEVEE SSR, and this tut ( mostly by the two screen grid images imgA imgB, I only read a little text and hardly read the code, then start writing my own code. )
Now just support OrthographicCamera. I'm trying to support PerspectiveCamera.

----------------EDIT 2----------------
Now support PerspectiveCamera. New PR: #20156

----------------EDIT----------------
Demo ScreenShot

[mrdoob]

Thanks for working on this!

Is this how's supposed to look like?

Also, it runs at ~5fps on my machine (MacBook Pro, Intel).

[gonnavis]

Hello Mr.doob

Yes, it is. I've already added the screenshot to the pr.
I know it's not look very well now, may need more advaced blur or anti-alias, and SSR has own limitations.
But I'm already satisfied with this reflection feeling.
My main goal now is to support PerspectiveCamera, after this, I will do in-depth study with the looking improvement.

I can run at 30fps at my win7 laptop with GTX 980M about 40% usage and 1920*1080 chrome maximized window.
The performance cost by the shader is mainly based on pixels count. May Mac retina monitor has too many pixels?
I'll consider these factors.

[gonnavis]

I found out that antialas was turned on and dpr was set before.
If turn them off, can reach about 12fps on Mac when the window is maximized.
If stepStride is set to 2, it can run to about 28fps.
Demo Demo2
Mac configuration

[Mugen87]

On my iMac I get only about 10 FPS which is definitely to low. Apart from the performance aspect, the visual appearance of the pass still looks buggy.

[gonnavis]

Yes, I just want to mention that the performance of this pass is not that bad on mac. I'll keep improving.

[gonnavis]

@mrdoob Hello Mr.doob

After use depthTexture instead of depthRenderTarget, the quality has been greatly improved.

I think it might be worth a second review now.

Demo

[mrdoob]

Nice! It is looking much better indeed!

[mrdoob]

Would it be hard to make this work with PerspectiveCamera too?

[gonnavis]

Thanks!

Yes, it’s difficult for me to judge the ray position of the current pixel with PerspectiveCamera.
Because of the perspective effect, cannot simply use these code

vec3 ray=(length(xy-d0)/totalLen)*(reflectDir*maxDistance);

I'm still trying in this branch
https://github.com/gonnavis/three.js/blob/SSRPassPerspective/examples/webgl_postprocessing_ssr.html
https://github.com/gonnavis/three.js/blob/SSRPassPerspective/examples/jsm/postprocessing/SSRPass.js
https://github.com/gonnavis/three.js/blob/SSRPassPerspective/examples/jsm/shaders/SSRShader.js

[gonnavis]

After just calc the distance from viewPosition to reflectRay using pointToLineDistance function, instead of calc the reflectRay position at this pixel, I think perspectiveCamera support is almost OK.

But it need more adjustments ( some may be already done in OrthographicSSRPass ), I'll keep improving.

Perspective Demo

[gonnavis]

After solving an obvious problem under the PerspectiveCamera, I think the SSRPass is ready to use.
So no need for OrthographicSSRPass now, I made a new PR #20156 .

[mrdoob]

This one can be closed then?

[gonnavis]

Yes, I'll merge these codes to SSRPass #20156.