///////////////////////////////////////////////////////////////////////////////
void Widget::Draw(int nesting) {
    if(!mAlreadyRendered) {
        if(IsVisible()) {
            auto parent = mParent.lock();
            if(parent) {
                GLCall(glStencilFunc(GL_EQUAL, nesting, 0xFF));
                GLCall(glStencilOp(GL_KEEP, GL_KEEP, GL_INCR));
            } else {
                GLCall(glStencilFunc(GL_ALWAYS, 1, 0xFF));
                GLCall(glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE));
            }

            CalculateGlobalPosition();

            PrepareVertices();

            auto label = dynamic_pointer_cast<Label>(shared_from_this());
            if(label) {
                if(label->GetFont()) {
                    GLCall(glBindTexture(GL_TEXTURE_2D, label->GetFont()->getTexture(label->GetCharacterSize()).getNativeHandle()));
                }
            } else {
                if(mTexture) {
                    GLCall(glBindTexture(GL_TEXTURE_2D, mTexture->mGLTexture));
                }
            }

            if(mVertices.size()) {
                const char* data = reinterpret_cast<const char*>(&mVertices[0]);
                GLCall(glVertexPointer(2, GL_FLOAT, sizeof(sf::Vertex), data + offsetof(sf::Vertex, position)));
                GLCall(glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(sf::Vertex), data + offsetof(sf::Vertex, color)));
                GLCall(glTexCoordPointer(2, GL_FLOAT, sizeof(sf::Vertex), data + offsetof(sf::Vertex, texCoords)));
                GLCall(glDrawArrays(GL_QUADS, 0, mVertices.size()));
            }

            for(auto & child : mChildren) {
                child->Draw(nesting + 1);
            }

            mAlreadyRendered = true;
        }
    }
}