Depth information

[Peter2]

I'm looking for the depth information (per pixel) of a camera's view on the scene:

• distance
• position: x,y,z

Currently I'm using the scene pick functionality for each pixel:

for x = 0 to maxX
   for y = 0 to maxY
      scene.pick(x,y,null,false,camera)

Then use the returned PickingInfo's distance and pickedPoint.

Is there a better/faster way to get the depth information, because the above mentioned code takes several seconds.

Maybe via a shader?

[Sebavan]

You can use the depth renderer for this:

https://doc.babylonjs.com/tutorials/How_to_use_DepthRenderer_to_get_depth_values

 

[Peter2]

Yes, but it does not give me the position.

[julien-moreau]

good question, do you want to use the positions in js side ? Or want to use in a shader like a post-process ?

[Peter2]

I like to have the information in JS code.

[Peter2]

I got the depth (via a shader) on a RenderTargetTexture visible on the screen.

But how can I retrieve the depth data from the texture (in JS code)?

Is there a way the walk from 0 to 1 for u and v and get the rgba data?

[NasimiAsl]

hi 

i use this solution before

why you need this data @Peter2 

[Peter2]

I like to output the following data to a file: distance, x, y, z

That is, for each frame of a camera.

[BitOfGold]

An example function (not tested for depth values, only rgb):

renderTargetTexture.onAfterRenderObservable.add(function () {  
   var pixels = self.engine.readPixels( 0, 0, xsize, ysize );
   //pixels is now a byte array of RGBA values?
}

[Peter2]

Yep, that well do it. Thx.

[Peter2]

Next step is to get the position (the pickedPoint). How to convert the vertex position into gl_FragColor?

[Peter2]

I got something like:

VertexShader:

varying vec4 vPosition;

void main(void) {
    vec4 pos = vec4(position, 1.0);
    vPosition = world * pos; 

    gl_Position = worldViewProjection * pos;
}

PixelShader:

varying vec4 vPosition;

void main(void) {
    gl_FragColor = vec4(vPosition.xyz / 255.0 + 0.5, 1.0);
}

Is this correct?

I'm losing precision this way I think.

[NasimiAsl]

you wanna do this?