I came across this while trying to do collision detection using mouse input.
From an answer to a recent question I asked I was trying to copy the ui::Widget collision detection mechanism for use manually e.g. the contents of ui::Widget::onTouchBegan which does collision detection based on the scene camera and the Widget object. To do this I had copied the relevant parts and was feeding my EventMouse location and this wasn’t working.
After some digging I’ve noted that it appears that the Touch events are in a different coordinate system to the Mouse ones. Notably Mouse events follow the documented coord system, Y axis 0 at top, while Touch uses Y axis 0 at bottom. It appears that the ui::Widget::hitTestmethod only works correctly with Touch events, which is confusing as they seem to be in the wrong coord system.
I’ve constructed a very simple test app to demonstrate the issue and for a mouse click in the center bottom of my window (1024x768) I get the following output:
Touch: {540.954, 3.62594}
Mouse Press: {540.954, 764.377}
Can anyone shed any light on whether this is correct behaviour and I’m just misunderstanding or if it really is some sort of bug?
Minimal example code:
#include "cocos2dx/cocos2d.h"
#include <iostream>
namespace cocos2d
{
std::ostream& operator<<(std::ostream& out, const cocos2d::Vec2& p)
{
out << "{" << p.x << ", " << p.y << "}";
return out;
}
}
namespace
{
auto const WIDTH = 1024;
auto const HEIGHT = 768;
class Cocos2dxApp : public cocos2d::Application
{
public: // interface
Cocos2dxApp()
{
auto director = cocos2d::Director::getInstance();
auto eglView = cocos2d::GLViewImpl::create("test_view");
eglView->setFrameSize(WIDTH, HEIGHT);
director->setOpenGLView(eglView);
eglView->setDesignResolutionSize(WIDTH, HEIGHT, ResolutionPolicy::EXACT_FIT);
auto displayLayer = cocos2d::Layer::create();
auto newScene = cocos2d::Scene::create();
auto mouseListener = cocos2d::EventListenerMouse::create();
auto touchListener = cocos2d::EventListenerTouchOneByOne::create();
mouseListener->onMouseDown = [](cocos2d::EventMouse* e)
{
std::cout << "Mouse Press: " << e->getLocation() << std::endl;
};
touchListener->onTouchBegan = [](cocos2d::Touch* t, cocos2d::Event* e)
{
std::cout << "Touch: " << t->getLocation() << std::endl;
return false;
};
director->getEventDispatcher()->addEventListenerWithFixedPriority(mouseListener, 1);
director->getEventDispatcher()->addEventListenerWithFixedPriority(touchListener, 1);
director->runWithScene(newScene);
newScene->addChild(displayLayer, 1);
}
bool applicationDidFinishLaunching() override { return true; }
void applicationDidEnterBackground() override {}
void applicationWillEnterForeground() override {}
};
}
int main(int argc, char** argv)
{
auto app = Cocos2dxApp();
app.run();
return 0;
}
