Cube Texture reflection size

[dbawel]

Great post - lots to learn here...

This is one of those days and this topic in particular by which my understanding of several processes in BJS has taken a leap in understanding how to manage reflections efficiently. I have loads of work to do, yet I find myself spending time I don't have to reconcile the many Playground examples posted here today.

I just hope I save enough time to actually get my work done.

DB

[GameMonetize]

This is the current computation:

https://github.com/BabylonJS/Babylon.js/blob/7317ed822e3e2d52a44966fa4d2fdc3b0a91291a/src/Shaders/ShadersInclude/reflectionFunction.fx#L42

So you suggest to replace it by this, correct?

vec3 viewDir = worldPos.xyz - vEyePosition;

mat4 reflectionMatrix = mat4(-1.,0.,0.,0.,0.,-1.,0.,0.,0.,0.,-1.,0.,0.,0.,0.,-1.);

vec3 coords = reflect(normalize(worldPos.xyz * 3.141592653589793 * length(viewDir) *.1 -
vEyePosition.xyz),worldNormal.xyz);

return vec3(reflectionMatrix * vec4(coords, 0));

So what is 0.1 here?

[NasimiAsl]

i don't know  but i think it is relation for camera fav (perspective) 

and about  reflectionMatrix   you need have a uniform like this 

[gamefan]

Wow, I am really glad a lot is happening here.. Too bad my understanding of the babylonjs internals is very little. I hope to learn very soon.

And I think its going to work for probes as well, adam got it working in his playgrounds. Nice

[adam]

1 minute ago, gamefan said:

adam got it working in his playgrounds

I didn't really do anything.  All credit goes to NasimiAsi and Deltakosh.

[gamefan]

Yeah, NasimiAsi made it work. Huge huge thanks to him. I was meaning to say that you got it working for probes, so his solution works.

[NasimiAsl]

@Deltakosh and all BABYLONJS Devs : don't forget finish this task. we are bug in reflection 

we can not see this bug in rounded mesh like sphere but we have it 

 

[GameMonetize]

I'm still waiting for a good candidate for "0.1" value

[GameMonetize]

And can you explain the math behind: 

vec3 coords = reflect(normalize(worldPos.xyz * 3.141592653589793 * length(viewDir) *.1 -
vEyePosition.xyz),worldNormal.xyz);

 

?

[adam]

This page might help:

http://www.physicsclassroom.com/calcpad/refln

[NasimiAsl]

i write what i think about that and why i change this parameters 

 

[GameMonetize]

to me it is more related to this: https://community.arm.com/groups/arm-mali-graphics/blog/2014/08/07/reflections-based-on-local-cubemaps

[NasimiAsl]

11 hours ago, Deltakosh said:

to me it is more related to this: https://community.arm.com/groups/arm-mali-graphics/blog/2014/08/07/reflections-based-on-local-cubemaps

where is the LocalCorrect in DefaultShader

 float3 viewDirWS = normalize(input.viewDirInWorld);
     float3 normalWS = normalize(input.normalInWorld);
     float3 reflDirWS = reflect(viewDirWS, normalWS);
     // Get local corrected reflection vector.
      float3 localCorrReflDirWS = LocalCorrect(reflDirWS, _BBoxMin, _BBoxMax,
                                                      input.vertexInWorld, _EnviCubeMapPos)
     // Lookup the environment reflection texture with the right vector.
    reflColor = texCUBE(_Cube, localCorrReflDirWS);

it is not Exactly what i append but very close to that

in localCorrect change the world pos and cube Map Pos at last with control min and max 

and after result it change ViewDirection i dont know about _BBoxMin and _BBoxMax (BindingBOX ? )

but we r not correct that

we have computeReflectionCoords this maybe calculate that but i know this not have Distance  parameters because we don't send any parameter about that

we just have ' vec4(vPositionW,1.0) '     ' normalW '

 // Find the ray intersection with box plane
    float3 invOrigVec = float3(1.0,1.0,1.0)/origVec;
    float3 intersecAtMaxPlane = (bboxMax - vertexPos) * invOrigVec;
    float3 intersecAtMinPlane = (bboxMin - vertexPos) * invOrigVec;
    // Get the largest intersection values (we are not intersted in negative values)
    float3 largestIntersec = max(intersecAtMaxPlane, intersecAtMinPlane);
    // Get the closest of all solutions
   float Distance = min(min(largestIntersec.x, largestIntersec.y), largestIntersec.z);
    // Get the intersection position
    float3 IntersectPositionWS = vertexPos + origVec * Distance;
    // Get corrected vector
    float3 localCorrectedVec = IntersectPositionWS - cubemapPos;
    return localCorrectedVec;

 

[Sebavan]

Hello,

The unity way is one  good trade off perf vs quality for local reflections and the one used in a few engines for local cube map. This works nicely without magic numbers.

http://www.babylonjs-playground.com/#1NP9BY#19

This would nevertheless require to be in another #define to avoid the cost of the computation in none local reflection and also be applied to refraction.

Hope that could help,

 

[GameMonetize]

Yep..there is no simple way to fix the default shader here. I would highly recommend to use @NasimiAsl version with ShaderBuilder.