Playing with shader

[Hartha]

Hello guys,

see the GIF please https://ibb.co/kZkrBR. 

I wonder how to do something like this in babylonjs, I did this in opengl project by sending a value to a uniform in fragment shader. should I do the same with babylonjs ? ; should I modify babylonjs shaders ?, or there is a better way to do that.

 

 

[Pryme8]

if(gl_FradCoords.y > amount)discard; or something like that on the shader

[Arte]

Hi Hartha,

mat.Fragment_Custom_Diffuse

[Hartha]

@Pryme8 and @Arte, Thank you guys very mush, very helpful answers, I have to update the amount "y", but it seems not to work when I put 

mat.Fragment_Custom_Diffuse('if( vPositionW.y  >'+ y +' ){ discard; }');

in registerBeforeRender, it just take the first call.
I will look to the implementation to find a solution.

Thank you very much again :).

[Arte]

@Hartha Could you show you problem using PG?

[Hartha]

Of course, https://playground.babylonjs.com/#AFRP1L#1

[Arte]

@Hartha It is not the best answer, but you need to change material dynamically each time. Working PG

[Hartha]

@Arte  Yes, it is not the best answer but it maybe be convenient to my case, Thanks Arte.

[Arte]

[Pryme8]

just build a custom shader from the default one so you keep all the rendering options, and add the new line of discard set to play off a uniform then just update your uniform on the before render function and you wont have to keep assigning the material.

[Arte]

@Pryme8 Can you provide sample? 

[Hartha]

@Pryme8 in CustomMaterial class there is a function to add a uniform, but I don't find how to update it, and in the StanderdMaterial class I find how to add and update a uniform but I don't know where to add a discard condition -.-.

Sorry for this but can you provide sample as Arte side ?

[GameMonetize]

Ping @NasimiAsl who is the father of the CustomMaterial

[Pryme8]

I would ask @NasimiAsl on how to add a uniform to the Custom Material, I have never used it.

but once you have it in place it should be as simple as material.setFloat('nameOfFloat', value); inside a render loop or pre render  loop.

but here is an example with setfloat
http://www.babylonjs-playground.com/#1L8D9Y

[NasimiAsl]

4 hours ago, Hartha said:

@Pryme8 in CustomMaterial class there is a function to add a uniform, but I don't find how to update it, and in the StanderdMaterial class I find how to add and update a uniform but I don't know where to add a discard condition -.-.

Sorry for this but can you provide sample as Arte side ?

hi

customMaterial and standardmaterial both can update uniform with this 

material.getEffect().setFloat() and others uniforms type

 @Hartha

Sample : https://playground.babylonjs.com/#AFRP1L#4

@Deltakosh 

Bug : https://playground.babylonjs.com/#AFRP1L#5

look line 48 ,49 50 

when a new mesh created or ( i think ) new standardMaterial created all set Effect function is freezed  is this depend to StandardMaterial

** for check you can set any Uniform in standard material 

notice that custom material inherited from standard material

 

[Hartha]

Thanks @NasimiAsl for help, I guess it is not a bug, you can see the log :
babylonjs WebGL: INVALID_OPERATION: uniform1f: location not for current program

it is means that the active shader program  is not the program which obtained the uniform locations from, we need to do something like gl.useProgram or update the uniform when we sure that the current active program is for the material we need to update.