create texture from bitmap

I wan to create texture from image rgb data. When the texture is rendered to the screen it shows nothing. I was just wondering if I missed something in the implementation:

Code:

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void GlWidget::createTextureFromBitmap(QByteArray btmp)
{
    /* create a 800 bye 600 * 3 texture from bitmap */
    tex.buf = new unsigned char[bytes.size()];
    memcpy(tex.buf, bytes.constData(), bytes.size());
    glGenTextures( 1, &tex.id);
    glBindTexture(GL_TEXTURE_2D, tex.id);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_LINEAR);
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
    glTexImage2D(     GL_TEXTURE_2D, 0, GL_RGB, 0, 0, 0, GL_RGB, GL_UNSIGNED_BYTE, tex.buf);
    gluBuild2DMipmaps(GL_TEXTURE_2D, GL_RGB, 800, 600, GL_RGB, GL_UNSIGNED_BYTE, tex.buf);
    delete [] tex.buf;
    tex.buf = NULL;
 
    updateGL();
}
 
 
void GlWidget::paintGL()
{
    shaderProgram.bind();
    shaderProgram.setUniformValue("mvpMatrix", pMatrix * vMatrix * mMatrix);
    shaderProgram.setUniformValue("texture", 0);
 
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, tex.id);
    //glActiveTexture(0);
 
    shaderProgram.setAttributeArray("vertex", vertices.constData());
    shaderProgram.enableAttributeArray("vertex");
    shaderProgram.setAttributeArray("textureCoordinate", textureCoordinates.constData());
    shaderProgram.enableAttributeArray("textureCoordinate");
 
    glDrawArrays(GL_TRIANGLES, 0, vertices.size());
 
    shaderProgram.disableAttributeArray("vertex");
    shaderProgram.disableAttributeArray("textureCoordinate");
    shaderProgram.release();
}

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If it shows nothing then maybe your drawing code is invalid. Does it render correctly if you replace the texture with a solid color?

Quote:

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Originally Posted by wysota

If it shows nothing then maybe your drawing code is invalid. Does it render correctly if you replace the texture with a solid color?

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It is fine now. I needed to adjust the camera position.

A GL texture is perfectly scalable, it is not composed of pixels.