Imagination PowerVR SDK Blog

Issue with float texture


#1

I’m trying to use the GL_OES_texture_float extension on ES2 PC emulator (win32).
Pixel type: GL_FLOAT
Pixel format: GL_RGB

However my object render is invisible or black if I override the alpha component to 1.0.
So it seems my texture contains only zeros.
My sample variable is well defined using highp qualifier.
My graphic card is: GeForce 8300 GS/PCI/SSE2

Am I missing something? Has anyone been there before?



#2

Is your texture mipmap complete, i.e. does it have all mipmap levels or are you using GL_NEAREST as the minification filter?


#3

I’m using GL_NEAREST and GL_CLAMP_TO_EDGE. I don’t want mipmap.


#4

I was trying to find an example in the SDK but I could not find any.


#5

I’ve added an extension requirement precompiler statement to my fragment shader:
#extension GL_OES_texture_float : require

That causes the compilation to return an error saying the extension is not supported. That’s funny cause the extensions string does mention GL_OES_texture_float.

Any thought? Do I need to configure the SDK in some ways for this to work?


#6

Could you please send narrowed example showing the issue you have described in your first post so we can reproduce it?Â

Regards,


#7

Unfortunately I can’t do that so easily cause the whole thing is part of a larger framework. When I get a chance I’ll try to implement a minimalistic example reproducing this issue as it seems the only way forward now.

On the other hand if someone had such a demo application showing basic usage of GL_OES_texture_float extension that would probably fix me up too.


#8

Here is the compilation error that I get when adding the “require” directive into my fragment shader:

ERROR: 0:8: Extension GL_OES_texture_float not supported
ERROR: 1 compilation errors. No code generated.

Still working on PC emulator with the graphic card mentioned above. glGetString(GL_EXTENSIONS) does contain GL_OES_texture_float.


#9

The GLSL #extension mechanism only applies to extensions to the language. GL_OES_texture_float does not extend the shading language.


#10

I see. Good to know. Thanks a lot for that answer.
So I don’t need to do anything to enable GL_OES_texture_float?
It should just work if supported right?


#11

Hi,

There is a bug within implementation of OES_texture_float. Our next release (SDK 2.7) will have it fixed.

Regards,


#12

Thanks for looking into this issue.
Do you have any indicative release date for that SDK 2.7?


#13

The 2.7 SDK should now be available from our website:

https://www.imgtec.com/powervr/insider/powervr-sdk.asp