CODEWITHSUNDEEP
openglopengl-es-2.0glsl
johnbakers
johnbakers

Reputation: 24750

Multiple instances of shaders

I recently read that you can

"have multiple instances of OpenGL shaders"

but no other details were given on this.

I'd like some clarification as to what exactly this means.

For one, I know you can have more than one glProgram running, and that you can switch between them. Is that all this is referring to? I assuming that switching between several created shader programs per frame would essentially mean I am using several programs "simultaneously".

Or does it somehow refer to having multiple "instances" of the same shader program? That would make no sense to me.

Some basic clarification would be enjoyed here!

Upvotes: 1

Views: 1221

Answers (1)

datenwolf
datenwolf

Reputation: 162164

When you create a program object you're linking together several shaders. Usually at least a vertex and a fragment shader. Now say you want to render, say some glow around some object. That glow would be created by a different fragment shader, but the vertex shader would be the same as for the regular appearance. Now to save resources you can use the same vertex shader in multiple programs but with different fragment shaders being linked in. Of course you could also have the same fragment shader and different vertex shaders.

In short you can link a single shader into an arbitrary number of programs. As long as the linked shader stages are compatible with each other this helps with modularization.

Upvotes: 6

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