void contextSwitch(QOpenGLContext *_context, ContextFunctor f) {
auto *_current = QOpenGLContext::currentContext();
if (!_current || !_current->isValid()) return;
if (_context != _current) {
_context->makeCurrent(_current->surface());
}
withCurrentContext(f);
if (_context != _current) {
_current->makeCurrent(_current->surface());
}
}
void useShader(QOpenGLShaderProgram& _s,
std::function<void(UniformHandler&)>f) {
withCurrentContext([&](QOpenGLFunctions& _gl) {
_s.bind();
{
UniformHandler _handler(_gl, _s);
f(_handler);
// Destructor of handler is called here implicitly
// by RAII to unbind all textures
}
_s.release();
});
}
void Image::update()
{
if (image_.width() == 0) return;
if (texture_) return;
withCurrentContext([&](QOpenGLFunctions& _) {
texture_.reset(new QOpenGLTexture(QOpenGLTexture::TargetRectangle));
texture_->setData(image_);
texture_->setMinMagFilters(
QOpenGLTexture::Linear,
QOpenGLTexture::Linear);
texture_->allocateStorage();
});
}
void Circle::drawLine(QPointF const& _pos, float _rX, float _rY) const
{
withCurrentContext([&](QOpenGLFunctions& _) {
glPushMatrix();
glScalef(_rX, _rY, 1.0);
glTranslatef(_pos.x() / _rX, _pos.y() / _rY, 0.0);
glEnableClientState(GL_VERTEX_ARRAY);
_.glBindBuffer(GL_ARRAY_BUFFER, vertexVbo_.id());
glVertexPointer(2, GL_FLOAT, 0, nullptr);
_.glDrawArrays(GL_LINE_LOOP, 1, numberSegments);
_.glBindBuffer(GL_ARRAY_BUFFER, 0);
glDisableClientState(GL_VERTEX_ARRAY);
glPopMatrix();
});
}
void InputPreview::paintGL()
{
if (!input() || !isVisible()) return;
makeCurrent();
if (!shader_) {
primaryContextSwitch([&](QOpenGLFunctions& _) {
visual::initShader(shader_,"textureRect");
});
}
withCurrentContext([this](QOpenGLFunctions& _)
{
_.glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
auto _rect = viewRect();
visual::viewport(this);
/// Setup orthogonal projection
glMatrixMode(GL_PROJECTION);
{
glLoadIdentity();
QMatrix4x4 _m;
_m.ortho(_rect.left(), _rect.right(), _rect.top(), _rect.bottom(), -1.0,
1.0);
glMultMatrixf(_m.constData());
}
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
shader_->bind();
_.glBindTexture(GL_TEXTURE_RECTANGLE, input_->textureId());
visual::Rectangle::draw(input_->size());
_.glBindTexture(GL_TEXTURE_RECTANGLE, 0);
shader_->release();
});
paintGLDone();
}