Irrlicht 3D Engine
 
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Tutorial 19: Mouse and Joystick

This tutorial builds on example 04.Movement which showed how to handle keyboard events in Irrlicht. Here we'll handle mouse events and joystick events, if you have a joystick connected and a device that supports joysticks. These are currently Windows, Linux and SDL devices.

#ifdef _MSC_VER
// We'll define this to stop MSVC complaining about sprintf().
#define _CRT_SECURE_NO_WARNINGS
#pragma comment(lib, "Irrlicht.lib")
#endif
#include <irrlicht.h>
#include "driverChoice.h"
using namespace irr;
Main header file of the irrlicht, the only file needed to include.
Everything in the Irrlicht Engine can be found in this namespace.
Definition aabbox3d.h:13

Just as we did in example 04.Movement, we'll store the latest state of the mouse and the first joystick, updating them as we receive events.

class MyEventReceiver : public IEventReceiver
{
public:
// We'll create a struct to record info on the mouse state
struct SMouseState
{
bool LeftButtonDown;
SMouseState() : LeftButtonDown(false) { }
} MouseState;
// This is the one method that we have to implement
virtual bool OnEvent(const SEvent& event)
{
// Remember the mouse state
{
switch(event.MouseInput.Event)
{
MouseState.LeftButtonDown = true;
break;
MouseState.LeftButtonDown = false;
break;
MouseState.Position.X = event.MouseInput.X;
MouseState.Position.Y = event.MouseInput.Y;
break;
default:
// We won't use the wheel
break;
}
}
// The state of each connected joystick is sent to us
// once every run() of the Irrlicht device. Store the
// state of the first joystick, ignoring other joysticks.
// This is currently only supported on Windows and Linux.
&& event.JoystickEvent.Joystick == 0)
{
JoystickState = event.JoystickEvent;
}
return false;
}
const SEvent::SJoystickEvent & GetJoystickState(void) const
{
return JoystickState;
}
const SMouseState & GetMouseState(void) const
{
return MouseState;
}
MyEventReceiver()
{
}
private:
SEvent::SJoystickEvent JoystickState;
};
Interface of an object which can receive events.
Axis aligned bounding box in 3d dimensional space.
Definition aabbox3d.h:22
@ EMIE_LMOUSE_LEFT_UP
Left mouse button was left up.
@ EMIE_LMOUSE_PRESSED_DOWN
Left mouse button was pressed down.
@ EMIE_MOUSE_MOVED
The mouse cursor changed its position.
@ EET_MOUSE_INPUT_EVENT
A mouse input event.
@ EET_JOYSTICK_INPUT_EVENT
A joystick (joypad, gamepad) input event.
u8 Joystick
The ID of the joystick which generated this event.
EMOUSE_INPUT_EVENT Event
Type of mouse event.
SEvents hold information about an event. See irr::IEventReceiver for details on event handling.
struct SJoystickEvent JoystickEvent
struct SMouseInput MouseInput
EEVENT_TYPE EventType

The event receiver for keeping the pressed keys is ready, the actual responses will be made inside the render loop, right before drawing the scene. So lets just create an irr::IrrlichtDevice and the scene node we want to move. We also create some other additional scene nodes, to show that there are also some different possibilities to move and animate scene nodes.

int main()
{
// ask user for driver
video::E_DRIVER_TYPE driverType=driverChoiceConsole();
if (driverType==video::EDT_COUNT)
return 1;
// create device
MyEventReceiver receiver;
IrrlichtDevice* device = createDevice(driverType,
core::dimension2d<u32>(640, 480), 16, false, false, false, &receiver);
if (device == 0)
return 1; // could not create selected driver.
if(device->activateJoysticks(joystickInfo))
{
std::cout << "Joystick support is enabled and " << joystickInfo.size() << " joystick(s) are present." << std::endl;
for(u32 joystick = 0; joystick < joystickInfo.size(); ++joystick)
{
std::cout << "Joystick " << joystick << ":" << std::endl;
std::cout << "\tName: '" << joystickInfo[joystick].Name.c_str() << "'" << std::endl;
std::cout << "\tAxes: " << joystickInfo[joystick].Axes << std::endl;
std::cout << "\tButtons: " << joystickInfo[joystick].Buttons << std::endl;
std::cout << "\tHat is: ";
switch(joystickInfo[joystick].PovHat)
{
case SJoystickInfo::POV_HAT_PRESENT:
std::cout << "present" << std::endl;
break;
case SJoystickInfo::POV_HAT_ABSENT:
std::cout << "absent" << std::endl;
break;
case SJoystickInfo::POV_HAT_UNKNOWN:
default:
std::cout << "unknown" << std::endl;
break;
}
}
}
else
{
std::cout << "Joystick support is not enabled." << std::endl;
}
core::stringw tmp = L"Irrlicht Joystick Example (";
tmp += joystickInfo.size();
tmp += " joysticks)";
device->setWindowCaption(tmp.c_str());
video::IVideoDriver* driver = device->getVideoDriver();
The Irrlicht device. You can create it with createDevice() or createDeviceEx().
virtual void setWindowCaption(const wchar_t *text)=0
Sets the caption of the window.
virtual scene::ISceneManager * getSceneManager()=0
Provides access to the scene manager.
virtual video::IVideoDriver * getVideoDriver()=0
Provides access to the video driver for drawing 3d and 2d geometry.
virtual bool activateJoysticks(core::array< SJoystickInfo > &joystickInfo)=0
Activate any joysticks, and generate events for them.
u32 size() const
Get number of occupied elements of the array.
Definition irrArray.h:368
The Scene Manager manages scene nodes, mesh recources, cameras and all the other stuff.
Interface to driver which is able to perform 2d and 3d graphics functions.
E_DRIVER_TYPE
An enum for all types of drivers the Irrlicht Engine supports.
unsigned int u32
32 bit unsigned variable.
Definition irrTypes.h:58

We'll create an arrow mesh and move it around either with the joystick axis/hat, or make it follow the mouse pointer.

smgr->addArrowMesh( "Arrow",
video::SColor(255, 255, 0, 0),
video::SColor(255, 0, 255, 0),
16,16,
2.f, 1.3f,
0.1f, 0.6f
)
);
node->setMaterialFlag(video::EMF_LIGHTING, false);
camera->setPosition(core::vector3df(0, 0, -10));
// As in example 04, we'll use framerate independent movement.
u32 then = device->getTimer()->getTime();
const f32 MOVEMENT_SPEED = 5.f;
while(device->run())
{
// Work out a frame delta time.
const u32 now = device->getTimer()->getTime();
const f32 frameDeltaTime = (f32)(now - then) / 1000.f; // Time in seconds
then = now;
bool movedWithJoystick = false;
core::vector3df nodePosition = node->getPosition();
if(joystickInfo.size() > 0)
{
f32 moveHorizontal = 0.f; // Range is -1.f for full left to +1.f for full right
f32 moveVertical = 0.f; // -1.f for full down to +1.f for full up.
const SEvent::SJoystickEvent & joystickData = receiver.GetJoystickState();
// We receive the full analog range of the axes, and so have to implement our
// own dead zone. This is an empirical value, since some joysticks have more
// jitter or creep around the center point than others. We'll use 5% of the
// range as the dead zone, but generally you would want to give the user the
// option to change this.
const f32 DEAD_ZONE = 0.05f;
moveHorizontal =
(f32)joystickData.Axis[SEvent::SJoystickEvent::AXIS_X] / 32767.f;
if(fabs(moveHorizontal) < DEAD_ZONE)
moveHorizontal = 0.f;
moveVertical =
(f32)joystickData.Axis[SEvent::SJoystickEvent::AXIS_Y] / -32767.f;
if(fabs(moveVertical) < DEAD_ZONE)
moveVertical = 0.f;
// POV hat info is only currently supported on Windows, but the value is
// guaranteed to be 65535 if it's not supported, so we can check its range.
const u16 povDegrees = joystickData.POV / 100;
if(povDegrees < 360)
{
if(povDegrees > 0 && povDegrees < 180)
moveHorizontal = 1.f;
else if(povDegrees > 180)
moveHorizontal = -1.f;
if(povDegrees > 90 && povDegrees < 270)
moveVertical = -1.f;
else if(povDegrees > 270 || povDegrees < 90)
moveVertical = +1.f;
}
if(!core::equals(moveHorizontal, 0.f) || !core::equals(moveVertical, 0.f))
{
nodePosition.X += MOVEMENT_SPEED * frameDeltaTime * moveHorizontal;
nodePosition.Y += MOVEMENT_SPEED * frameDeltaTime * moveVertical;
movedWithJoystick = true;
}
}
// If the arrow node isn't being moved with the joystick, then have it follow the mouse cursor.
if(!movedWithJoystick)
{
// Create a ray through the mouse cursor.
receiver.GetMouseState().Position, camera);
// And intersect the ray with a plane around the node facing towards the camera.
core::plane3df plane(nodePosition, core::vector3df(0, 0, -1));
core::vector3df mousePosition;
if(plane.getIntersectionWithLine(ray.start, ray.getVector(), mousePosition))
{
// We now have a mouse position in 3d space; move towards it.
core::vector3df toMousePosition(mousePosition - nodePosition);
const f32 availableMovement = MOVEMENT_SPEED * frameDeltaTime;
if(toMousePosition.getLength() <= availableMovement)
nodePosition = mousePosition; // Jump to the final position
else
nodePosition += toMousePosition.normalize() * availableMovement; // Move towards it
}
}
node->setPosition(nodePosition);
// Turn lighting on and off depending on whether the left mouse button is down.
node->setMaterialFlag(video::EMF_LIGHTING, receiver.GetMouseState().LeftButtonDown);
driver->beginScene(true, true, video::SColor(255,113,113,133));
smgr->drawAll(); // draw the 3d scene
driver->endScene();
}
virtual u32 getTime() const =0
Returns current virtual time in milliseconds.
virtual bool run()=0
Runs the device.
virtual ITimer * getTimer()=0
Provides access to the engine's timer.
T X
X coordinate of the vector.
Definition vector3d.h:408
vector3d< T > & normalize()
Normalizes the vector.
Definition vector3d.h:168
T Y
Y coordinate of the vector.
Definition vector3d.h:411
Scene Node which is a (controlable) camera.
virtual core::line3d< f32 > getRayFromScreenCoordinates(const core::position2d< s32 > &pos, ICameraSceneNode *camera=0)=0
Returns a 3d ray which would go through the 2d screen coodinates.
virtual void drawAll()=0
Draws all the scene nodes.
virtual ISceneCollisionManager * getSceneCollisionManager()=0
Get pointer to the scene collision manager.
virtual IMeshSceneNode * addMeshSceneNode(IMesh *mesh, ISceneNode *parent=0, s32 id=-1, const core::vector3df &position=core::vector3df(0, 0, 0), const core::vector3df &rotation=core::vector3df(0, 0, 0), const core::vector3df &scale=core::vector3df(1.0f, 1.0f, 1.0f), bool alsoAddIfMeshPointerZero=false)=0
Adds a scene node for rendering a static mesh.
virtual ICameraSceneNode * addCameraSceneNode(ISceneNode *parent=0, const core::vector3df &position=core::vector3df(0, 0, 0), const core::vector3df &lookat=core::vector3df(0, 0, 100), s32 id=-1, bool makeActive=true)=0
Adds a camera scene node to the scene graph and sets it as active camera.
virtual IAnimatedMesh * addArrowMesh(const io::path &name, video::SColor vtxColorCylinder=0xFFFFFFFF, video::SColor vtxColorCone=0xFFFFFFFF, u32 tesselationCylinder=4, u32 tesselationCone=8, f32 height=1.f, f32 cylinderHeight=0.6f, f32 widthCylinder=0.05f, f32 widthCone=0.3f)=0
add a static arrow mesh to the meshpool
Scene node interface.
Definition ISceneNode.h:41
virtual void setPosition(const core::vector3df &newpos)
Sets the position of the node relative to its parent.
Definition ISceneNode.h:507
void setMaterialFlag(video::E_MATERIAL_FLAG flag, bool newvalue)
Sets all material flags at once to a new value.
Definition ISceneNode.h:425
virtual const core::vector3df & getPosition() const
Gets the position of the node relative to its parent.
Definition ISceneNode.h:498
virtual bool beginScene(bool backBuffer=true, bool zBuffer=true, SColor color=SColor(255, 0, 0, 0), const SExposedVideoData &videoData=SExposedVideoData(), core::rect< s32 > *sourceRect=0)=0
Applications must call this method before performing any rendering.
virtual bool endScene()=0
Presents the rendered image to the screen.
Class representing a 32 bit ARGB color.
Definition SColor.h:202
float f32
32 bit floating point variable.
Definition irrTypes.h:104
unsigned short u16
16 bit unsigned variable.
Definition irrTypes.h:40

In the end, delete the Irrlicht device.

device->drop();
return 0;
}
bool drop() const
Drops the object. Decrements the reference counter by one.