A Shader Que.

[keprast]

hi，guy.

There is a problem with pixel shaders.
I code extern number time,
I called the function shader: send (“time”,x) to send the value.

error：
a common error is not define but not use the variable.
why？

[raidho36]

You never used the variable in the code so it got pruned away during shader compilation. After that, you're trying to use it but it doesn't exist.

[keprast]

You never used the variable in the code so it got pruned away during shader compilation. After that, you're trying to use it but it doesn't exist.

So I should write code like that, right?
extern number time = 0;

[keprast]

You never used the variable in the code so it got pruned away during shader compilation. After that, you're trying to use it but it doesn't exist.

I think that's wrong, obviously I need an init value to maintain this variable, right?
in love.load？

[grump]

You have to actually use the variable in the shader. Not just declare it. It has to be referenced somewhere in the shader code, or else the shader compiler will remove it.

Please use the Support subforum for future help requests.

[keprast]

You have to actually use the variable in the shader. Not just declare it. It has to be referenced somewhere in the shader code, or else the shader compiler will remove it.

Please use the Support subforum for future help requests.

error：
assign：I-value required “time”(can’t modfiy a unifrom )

[pgimeno]

Just add this at the beginning of your code:

Code: Select all

do
  local mt = debug.getregistry().Shader
  local old_send = mt.send
  mt.send = function (shader, variable, ...)
    pcall(old_send, shader, variable, ...)
  end  
end

This should be the default behaviour, but the LÖVE developers don't seem to agree.

[keprast]

Just add this at the beginning of your code:

Code: Select all

do
  local mt = debug.getregistry().Shader
  local old_send = mt.send
  mt.send = function (shader, variable, ...)
    pcall(old_send, shader, variable, ...)
  end  
end

This should be the default behaviour, but the LÖVE developers don't seem to agree.

Thank you, the API manual doesn't say anything about it

[raidho36]

All errors should be explicit. The game may choose to ignore errors, but the engine shall never fail silently.

[pgimeno]

Normally I would agree, but this is why I disagree in this case: viewtopic.php?p=222744#p222744

Full previous discussion with Slime starts here: viewtopic.php?p=207865#p207865

The OpenGL wiki recommends ignoring the error, keeping in mind the possibility of a misspelled name: https://www.khronos.org/opengl/wiki/GLS ... iveUniform