Crash when calling glBufferData

[cryovat]

Hi,

First of all, thanks for your work on this library!

I've been tinkering with it for some time now, but whenever I try to use vertex buffer objects, I always end up crashing hard when trying to get data into the buffer. I'm using code like the following:

(define verts (make-f32vector 16))
(define verts-size (* (ctype-sizeof _float) (f32vector-length verts)))
(define vbo (u32vector-ref (glGenBuffers 1) 0))
(glBindBuffer GL_ARRAY_BUFFER vbo)
(glBufferData
           GL_ARRAY_BUFFER
           (s32vector verts-size) ; Length of array in bytes
           (f32vector->cpointer verts) ; Causes crash, #f is fine
           GL_STATIC_DRAW)

Is the crash caused by errors in my code, or is there any deeper issues at play here?

[stephanh42]

Hi Cryovat,

This seems definitely a bug in the RacketGL binding.

The second parameter of glBufferData should simply be an integer, not a vector, but the binding incorrectly requires a vector.

If you are adventurous, the following should fix it (untested):

Replace in readspec.rkt the line

(cons "GLsizeiptr" (pointer-to '_int32))

by

(cons "GLsizeiptr" '_int32)

and then regenerate the bindings.

Please note that I haven't tested VBOs at all yet, so expect some roughness along the way.

Stephan

On 13-05-12 23:33, cryovat wrote:

Hi,

First of all, thanks for your work on this library!

I've been tinkering with it for some time now, but whenever I try to use vertex buffer objects, I always end up crashing hard when trying to get data into the buffer. I'm using code like the following:

(define verts (make-f32vector 16))
(define verts-size (* (ctype-sizeof _float) (f32vector-length verts)))
(define vbo (u32vector-ref (glGenBuffers 1) 0))
(glBindBuffer GL_ARRAY_BUFFER vbo)
(glBufferData
            GL_ARRAY_BUFFER
            (s32vector verts-size) ; Length of array in bytes
            (f32vector->cpointer verts) ; Causes crash, #f is fine
            GL_STATIC_DRAW)

Is the crash caused by errors in my code, or is there any deeper issues at play here?

---

Reply to this email directly or view it on GitHub: https://github.com/stephanh42/RacketGL/issues/4

[stephanh42]

I pushed this change (actually with _intptr rather than _int32).

[cryovat]

Wow, thank you for the incredibly fast reply and fix. You rock! :-)