CODEWITHSUNDEEP
qtopenglglewqglwidgetqt5.3
Denis
Denis

Reputation: 758

glActiveTexture in Qt and QGLWidget?

I have a small application on OpenGL+GLEW. Now, I am trying to rewrite it with QT(instead of GLEW). But I have a problem. IDE writes:

'glActiveTexture' was not declared in this scope glActiveTexture(TextureUnit); ^

Here is that code in .cpp file:

#include <iostream>
#include "texture.h"

Texture::Texture(GLenum TextureTarget, std::string& FileName)
{
    m_textureTarget = TextureTarget;
    m_fileName      = FileName;
}

bool Texture::Load()
{
    // A lot of code for reading the picture.
}

void Texture::Bind(GLenum TextureUnit)
{
    glActiveTexture(TextureUnit);
    glBindTexture(m_textureTarget, m_textureObj);
}

Here is code from .h file.

#ifndef TEXTURE_H
#define TEXTURE_H

#include <string>
#include <QGLWidget>

class Texture
{
public:
    Texture(GLenum TextureTarget, std::string& FileName);

    bool Load();

    void Bind(GLenum TextureUnit);

private:
    std::string m_fileName;
    GLenum m_textureTarget;
    GLuint m_textureObj;
    unsigned int width, height;
    unsigned char * data;
};


#endif  /* TEXTURE_H */

I am starting to think that Qt doesn't present such capabilities. How can I solve this problem? I would be glad to any ideas.

Upvotes: 0

Views: 1614

Answers (1)

derhass
derhass

Reputation: 45332

For anything beyond GL 1.1 (and glActiveTexture is beyond that), you have to use OpenGL's extension mechanism. Qt can do that for you all under the hood, have a look at the QAbstractOpenGLFunctions class hierarchy

You can get the context the widget has created via QOpenGLWidget::context and the QAbstractOpenGLFunctions of the context via QOpenGLContext::versionFunctions(). There is also the older QOpenGLFunctions class available via QOpenGLContext::functions() which is limited to GL ES 2.0 (and the smathcing ubset of desktop GL 2.0), but would be enough for glActiveTexture().

Upvotes: 1

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