Render Texture (Draw)

gistfile1.txt

    auto render_texture = RenderTexture::create(this->getContentSize().width, this->getContentSize().height);
    render_texture->setPosition(this->getContentSize() / 2);
    this->addChild(render_texture, 10000);
    
    auto brush = Sprite::create("water.png");
    brush->retain();
    
    auto draw_overlay = ui::Layout::create();
    draw_overlay->setContentSize(this->getContentSize());
    draw_overlay->setTouchEnabled(true);
    this->addChild(draw_overlay, 9999);
    
    draw_overlay->addTouchEventListener([this, render_texture, brush](Ref * sender, ui::Widget::TouchEventType type) {
        auto wg = reinterpret_cast<ui::Widget *>(sender);
        auto current_point = wg->getTouchMovePosition();
        if (last_point == Point::ZERO) {
            last_point = current_point;
            return;
        }
        
        render_texture->begin();
        
        auto distance = current_point.distance(last_point);
        for (float i = 0; i < distance; i += 0.5) {
            float difx = last_point.x - current_point.x;
            float dify = last_point.y - current_point.y;
            float delta = (float)i / distance;
            auto pos = Point(current_point.x + (difx * delta), current_point.y + (dify * delta));
            brush->setPosition(pos);
            brush->visit();
        }
        render_texture->end();
        last_point = current_point;
    });