[Mesa-dev] [Bug 49996] New: DH61AG - HD Graphics 3000 - OpenGL sampler objects on Ubuntu Linux 12.04 do not work

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=49996

             Bug #: 49996
           Summary: DH61AG - HD Graphics 3000 - OpenGL sampler objects on
                    Ubuntu Linux 12.04 do not work
    Classification: Unclassified
           Product: Mesa
           Version: unspecified
          Platform: x86 (IA32)
        OS/Version: Linux (All)
            Status: NEW
          Severity: normal
          Priority: medium
         Component: Mesa core
        AssignedTo: mesa-dev at lists.freedesktop.org
        ReportedBy: mark.newiger at seefront.com


Configuration:
- Intel SandyBridge PC Mainboard DH61AG and integrated Intel HD Graphics 3000
- Dual OS: Windows 7 32bit and Ubuntu 12.04 32bit

When using OpenGL sampler objects for configuring textures, on Ubuntu Linux you
have to create a mipmap chain by calling “glGenerateMipmap()”. Otherwise the
texture sampling will not work (e.g. returns black).
Take the following example:
// Init
int texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(…);

int sampler;
glGenSamplers(1, &sampler);
glSamplerParameteri(sampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glSamplerParameteri(sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

// Render loop
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture);
glBindSampler(0, sampler);
…

This works perfectly on Windows but not on Ubuntu Linux. For Ubuntu Linux I
have to add the following:
//Init
…
glTexImage2D(…);
glGenerateMipmap(GL_TEXTURE_2D);

Without the mipmap the texture sampling does not work, although mipmaps are not
used. When using the traditional texture filter configuration, this problem
does not occur and the code behaves the same on Windows and Linux:
// Render loop
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

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