QOpenGLShaderProgram add QOpenGLShader uniform location -1

Dimitris

Hi there,

I'm playing around with the triangle example. What I saw is that if I use the QOpenGLShader classes to create the vertex and fragment shaders (instead of add the source string directly) and then add them to a QOpenGLShaderProgram object, getting the uniform location of the matrix returns -1.

Here it is the code:

'''void TriangleWindow::initialize()
{

  QOpenGLShader *vertexShader = new QOpenGLShader(QOpenGLShader::Vertex);
if (!vertexShader->compileSourceFile(QDir::currentPath() + "/vertexshader.vert"))
{
    qDebug() << vertexShader->log();
}
QOpenGLShader *fragmentShader = new QOpenGLShader(QOpenGLShader::Fragment);
if (!fragmentShader->compileSourceFile(QDir::currentPath() + "/fragmentshader.frag"))
{
    qDebug() << fragmentShader->log();
}

m_program = new QOpenGLShaderProgram(this);
if (!m_program->addShader(vertexShader)) qDebug() << "Cannot add vertex shader\n";
if (!m_program->addShader(fragmentShader)) qDebug() << "Cannot add fragment shader\n";
if (!m_program->link())
qDebug() << m_program->log();

 m_program->bind();

m_posAttr = m_program->attributeLocation("posAttr");
if (m_posAttr == -1) qDebug() << "Cannot find position\n";
m_colAttr = m_program->attributeLocation("colAttr");
if (m_colAttr == -1) qDebug() << "Cannot find colors\n";
m_matrixUniform = m_program->uniformLocation("matrix");
if (m_matrixUniform == -1) qDebug() << "Cannot find matrix\n";'''

Am I doing somthing wrong? The shader files hold exactly the same code as the shader string of the example.

Cheers,
Dimitris

Dimitris

I found my problem. It was my mistake

SGaist

Hi and welcome to devnet,

What mistake was it ? That may help other users

Dimitris

Hi,

I feel very bad for saying this. I was reading another shader file were the uniform matrix variable wasn't used. And the compiler gets rid of those variables. It was a very stupid mistake!!

Cheers

SGaist

Don't worry, that kind of things can happen

Happy coding !