What exactly does glEnableVertexAttribArray do?
OpenglOpengl Problem Overview
I was reading: Dissecting Display, Chapter 1. Hello, Triangle!.
What exactly does glEnableVertexAttribArray do? I think it enables the use of a given VBO, but I am not sure.
I thought that is what glEnableClientState(GL_VERTEX_ARRAY) did.
Opengl Solutions
Solution 1 - Opengl
> I have been reading: Dissecting Display, Chapter 1. Hello, Triangle!.
Then please read the next page; I explain exactly what it does there ;)
If I may quote myself:
> We assigned the attribute index of the position attribute to 0 in the vertex shader, so the call to glEnableVertexAttribArray(0) enables the attribute index for the position attribute. [...] If the attribute is not enabled, it will not be used during rendering.
Solution 2 - Opengl
It's similar to a vertex array but stores additional extra values for each point rather than it's coordinates. You might want to store a temperature, density, signal strength at each point in a modelling app for example, or perhaps a damage value for a game
Solution 3 - Opengl
There is another way to specify data for a vertex attribute, the non-array way:
In this way, we specify data for only one vertex, this data will be replicated for all vertices.
To use non-array data, call glDisableVertexAttribArray.
To use array data, call glEnableVertexAttribArray.