---
title: GLKit Effects Constants
framework: GLKit
role: collectionGroup
role_heading: API Collection
path: glkit/glkit-effects-constants
---

# GLKit Effects Constants

## Overview

Overview GLKit effects implement shaders to perform their calculations. These shaders require vertex data to be provided by your application. All of the effects provided by GLKit use a consistent set of indices to reference vertex data provided by your application. When your application enables a vertex attribute array by calling the glEnableVertexAttribArray function, or specifies the vertex attribute pointer by calling the glVertexAttribPointer function, it uses one of these constants to specify the index parameter.

## Topics

### Constants

- [GLKVertexAttrib](glkit/glkvertexattrib.md)

## See Also

### Rendering Effect Parameters

- [GLKEffectProperty](glkit/glkeffectproperty.md)
- [GLKEffectPropertyFog](glkit/glkeffectpropertyfog.md)
- [GLKEffectPropertyLight](glkit/glkeffectpropertylight.md)
- [GLKEffectPropertyTexture](glkit/glkeffectpropertytexture.md)
- [GLKEffectPropertyMaterial](glkit/glkeffectpropertymaterial.md)
- [GLKEffectPropertyTransform](glkit/glkeffectpropertytransform.md)