search

mdn / content

The content behind MDN Web Docs
https://developer.mozilla.org
Other
9.1k stars 22.46k forks source link

vertexAttribPointer() type only accepts floating point types #28425

Open randfur opened 1 year ago

randfur commented 1 year ago

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext/vertexAttribPointer

What specific section or headline is this issue about?

https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext/vertexAttribPointer#parameters

What information was incorrect, unhelpful, or incomplete?

I tried using gl.UNSIGNED_INT but kept getting WebGL warning: drawArraysInstanced: Vertex attrib 0 requires data of type UINT, but is being supplied with type FLOAT. errors.

What did you expect to see?

Turns out I have to use https://developer.mozilla.org/en-US/docs/Web/API/WebGL2RenderingContext/vertexAttribIPointer instead for integer types.

Do you have any supporting links, references, or citations?

https://stackoverflow.com/a/17261259/866521

Do you have anything more you want to share?

No response

MDN metadata

Page report details * Folder: `en-us/web/api/webglrenderingcontext/vertexattribpointer` * MDN URL: https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext/vertexAttribPointer * GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/api/webglrenderingcontext/vertexattribpointer/index.md * Last commit: https://github.com/mdn/content/commit/eda49877b9078b24cd18f794470e5e225add9b94 * Document last modified: 2023-04-08T06:46:30.000Z
vallentin commented 5 months ago

This issue can be closed.

It is not an issue with the docs, it's a misunderstanding of how to use vertexAttribPointer() vs vertexAttribIPointer() (I for Integer).

I answered this (again) on Stack Overflow the other day.

In short the type in vertexAttribPointer() is not the data type in the shader. It's the data type of the data stored in the vertex buffer. In other words, vertexAttribPointer() tells that the shader is receiving floats. However, the actual data in the vertex buffer can be floats, unsigned integers, bytes, etc. But in the end they are converted (normalized or not) into floats.

Whereas, if you want to receive integers in the shader. Then you need to use vertexAttribIPointer() (I for Integer). Again the data type is the data type in the vertex buffer.