[1.7.10] rendering a texture in greyscale

[sigurd4]

i've made a gui where i render a texture, but i want it to automatically be in greyscale, or preferably in an amber-like colour. this is what it looks like currently:

it uses the skin of the owner of the item, thus i cannot alter the texture. i'm not very familiar with openGL, but i know how  to do some things, like render 2D textures, change brightness of the image, change renderpass, rotate and offset, but not how to do this. i've been trying out the GL11.glColor3f() function, but i don't quite inderstand it yet. (i thought the three different values were rgb, but doing a bit of testing it doesnt seem like this is the case.) how do i do this?

[Draco18s]

Shaders.

[sigurd4]

that's not really helpful at all. doesn't shaders change the rendering stuff for everything? because i only want the steve in the bottom-right corner to be in greyscale. also, i have no idea on how to make a new shader, though i have altered the vanilla ones before (without quite understanding what i was doing). surely there's an easier way?

[Abastro]

that's not really helpful at all. doesn't shaders change the rendering stuff for everything? because i only want the steve in the bottom-right corner to be in greyscale. also, i have no idea on how to make a new shader, though i have altered the vanilla ones before (without quite understanding what i was doing). surely there's an easier way?

No, Shaders only changes objects which they were applied to.

And No again, there is no easier way then shaders to render grayscale.(You cannot do that only with GL11)

Maybe modifying texture would work, but it would not be any easier..

[Draco18s]

Maybe modifying texture would work, but it would not be any easier..

 

Not to mention that it's almost impossible to get access to the bitmap data...

[sigurd4]

well nvm... i wont bother with that just for such a little detail.