How can I use glGenSamplers in OpenGL version 3.2 ?

hesheit

As stated in OpenGL reference webpage, glGenSamplers is first provided in the version 3.3. but how it can be used through the version 3.2 in Qt5.

? Offline

Hi,

If your OpenGL implementation supports it there are extension classes that can help you here. They are in a new static module called QtOpenGLExtensions. To enable this add:

@
QT += openglextensions
@

to your .pro file. Then, once you have your OpenGL 3.2 context instantiate a suitable extension class and initialize it with something like:

@
QOpenGLExtension_ARB_sampler_objects* ext = new QOpenGL_ARB_sampler_objects;
if (!ext->initializeOpenGLFunctions())
qWarning() << "Could not resolve sampler function pointers";
@

Then use the functions as needed:

@
GLuint m_samplerId;
...
ext->glGenSamplers(1, &m_samplerId);
...
@

I'm also hoping to add QOpenGLSampler and QpenGLTexture to Qt 5.2.

? Offline

Note however, that OS X doesn't support sampler objects until OS X Mavericks is released.

hesheit

Thank you ZapB.

Now Im using OS X and I am going to implement it with the old-fashioned style by following codes

@// Bind the texture
m_funcs->glActiveTexture( GL_TEXTURE0);
texture->bind();

    // Associate with sampler uniform in shader
    QString samplerName = sampler->getSamplerNameInShaderProgram();
    GLuint samplerLoc = m_shader_program->uniformLocation(samplerName);
    m_shader_program->setUniformValue(samplerLoc, unit);@

Do you think it will work?

? Offline

Oh sorry I thought you meant OpenGL sampler objects but you actually mean GLSL texture sampler opaque types. Yes that should work fine.