Non null-terminated C strings sended to OpenGL functions.
- Program started with GHC started like runhaskell does
- debuggued with gDEBugger (OpenGL debug)
Consider the following code :
borderBind <- get $ programVars "borderColor"
shadowBind <- get $ programVars "shadowColor"
mathBind <- get $ uniformLocation txtProg "mathAlpha"
alphaBind <- get $ uniformLocation txtProg "genAlpha"I'm using it to retrieve the location of some variables in some shaders, the problem is the real value sended to OpenGL : < see image 1 >
They are not null-terminated, and this way, sending some garbage appended at the end of the string.
I've tested a little work-around :
borderBind <- get $ programVars "borderColor\0"
shadowBind <- get $ programVars "shadowColor\0"
mathBind <- get $ uniformLocation txtProg "mathAlpha\0"
alphaBind <- get $ uniformLocation txtProg "genAlpha\0"And this way I'm able to recover the location normally.
<see image2>
After digging, the problem seem to be in Graphics.Rendering.OpenGL.GL.Shaders, with the function withGLStringLen. This function is using withCAStringLen which acording to documentation ( http://haskell.org/ghc/docs/latest/html/libraries/base/Foreign-C-String.html#v%3AwithCAStringLen ) doesn't provide any assurance about the null termination.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 6.8.3 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | libraries/HGL |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |