Need some help on some things

[cgcgames2]

ok i think im starting to some what get it. GetIrrIn is the back and front of ship. but what i dont get is how on earth those that come from the code inside hehe.

also is there anyway to do the same with rotations?.

i just wish i understude more about 3d code lol. i mean i know C++ but this is almost another laungauge XD. . But im sure ill get it eventrally everyone has to spend time learning.

[cgcgames2]

Good news i am really starting to get it now .

i have managed to code it so that when you turn without pressing w it will now drift.

i am starting to understand the GetIrrIn function you made. however i still am not getting the matrix part.

what exactly is 8 9 10 working out?

becuase i saw the other onces where like 5 6 7.

anyway thanks again for this help. its really helped me learn how to use the engine.

Jordan

[Seven]

http://www.j3d.org/matrix_faq/matrfaq_latest.html

Code: Select all

Q3.  How do I represent a matrix using the C/C++ programming languages?
-----------------------------------------------------------------------
  The simplest way of defining a matrix using the C/C++ programming
  languages is to make use of the "typedef" keyword. Both 3x3 and 4x4
  matrices may be defined in this way ie:

    typedef float MATRIX3[9];
    typedef float MATRIX4[16];

    Since each type of matrix has dimensions 3x3 and 4x4, this requires
  9 and 16 data elements respectively.
  At first glance, the use of a single linear array of data values may
  seem counter-intuitive. The use of two dimensional arrays may seem
  more convenient ie.

    typedef float MATRIX3[3][3];
    typedef float MATRIX4[4][4];

  However, the use of two reference systems for each matrix element
  very often leads to confusion. With mathemetics, the order is row
  first (i), column second (j) ie.

     Mij

  Using C/C++, this becomes

     matrix[j][i]

     Using two dimensional arrays also incurs a CPU performance penalty in
  that C compilers will often make use of multiplication operations to
  resolve array index operations.
  So, it is more efficient to stick with linear arrays. However, one issue
  still remains to be resolved. How is an two dimensional matrix mapped
  onto a linear array? Since there are only two methods (row first/column
  second or column first/row column).
  The performance differences between the two are subtle. If all for-next
  loops are unravelled, then there is very little difference in the
  performance for operations such as matrix-matrix multiplication.
  Using the C/C++ programming languages the linear ordering of each
  matrix is as follows:

  mat[0]  = M        mat[3]  = M
             00                 03
  mat[12] = M        mat[15] = M
             30                 33

	|  0  1  2  3 |
        |             |              | 0 1 2 |
        |  4  5  6  7 |              |       |
    M = |             |          M = | 3 4 5 |
        |  8  9 10 11 |              |       |
        |             |              | 6 7 8 |
        | 12 13 14 15 |

[cgcgames2]

thanks

ill have a read though that now. there is a few things i dont get now but maybe ill get when i have read through the matrix.

one is i want the ship to aply thrust based on its old vector. i was thinking of trying to do somthing where it would then look at the old vector and move along the old vector but each time it does the loop. While w is down, it does somthing to move the old vector closer to the new vector based on its thrust. so instead of just drifting, then when you press w it jumps to the new vector strait away, it would now slowly move to the new vector over the time you thrust.

I know what i need to do just dont really know how to code it hehe .

same with banking and rotating that i cant figure out. anyway let me go through what you sent me. and see if i can work out from there.

[cgcgames2]

ok i read though it all. but my thing i dont get is how did you know that mat[8] mat[9] and mat[10] in the matrix array would find the forward vector of the model.

i have a felling ill have to use vectors to make the banking to work. i tried to get it working but im not sure how to make the ship only rotat to a certain point after the A key has been pressed.

im still working on my code and finding new things every day. so im sure ill get there eventrally .

anyway thanks again for you help

[Seven]

np. I looked at the video you posted and thought it was pretty cool. I wont be online again until wed? or so and will be able to look at it on a dev system then. When I do, i think i will write some code to simulate the video. Like i say, it was pretty cool and it will give me a chance to try some stuff that I wanted to look at. Anyhow, see you on wed.

[cgcgames2]

if you could do that it would be great . thanks so much for all your help.

i been trying to do it my self i just cant seem to get the code right. also since im working with a groube of 5 people (3 of them are coders including me) im thinking of making this my last bit of code i do for 3d stuff XD. dont get me wronge ill still spend time learning. but i think i might stick with the interface code and the chat system lol . Ill also probs be working on the models and graphics side of things now .

however i am starting to enjoy the 3d code a little bit. i just wished i knew more about it .

anyway i cant wait to see what you get with the movment. i can show you how i did drifting if you want. dont look at the rotation code. the a and d work fine but my effort to try and make code where it wouldnt just jump when your press w. was extremly bad lol. was trying to get the old vector verse the new vector and rotat the old vector while w is down until oldvector == newvector.

i am pretty close with the code i just screewed it up lol .

anyway here is the code i did.

Code: Select all

#ifdef _MSC_VER

#define _CRT_SECURE_NO_WARNINGS
#pragma comment(lib, "Irrlicht.lib")
#endif

#include <irrlicht.h>
#include "driverChoice.h"

using namespace irr;
using namespace core;
using namespace scene;
using namespace video;
using namespace io;
using namespace gui;


vector3df GetIrrIn(ISceneNode* node)
{
         matrix4 mat = node->getRelativeTransformation();
         vector3df in(mat[8],mat[9],mat[10]);
         in.normalize();
         return in;
}

vector3df GetIrrUp(ISceneNode* node)
{
         matrix4 mat = node->getRelativeTransformation();
         vector3df up(mat[4],mat[5],mat[6]);
         up.normalize();
         return up;
}

vector3df GetIrrLeft(ISceneNode* node)
{
        matrix4 mat = node->getRelativeTransformation();
         vector3df left(mat[0],mat[1],mat[2]);
         left.normalize();
         return left;
}

vector3df GetPointInFront(ISceneNode* node, float distance)   
{   
       vector3df p = node->getPosition();
       p += distance * GetIrrIn(node);
       return p;   
};

vector3df GetPointInBack(ISceneNode* node,float distance)   
{   
      vector3df p = node->getPosition();
      p -= distance * GetIrrIn(node);
      return p;   
};
 
vector3df GetPointAbove(ISceneNode* node,float distance)     
{   
      vector3df p = node->getPosition();
      p += distance * GetIrrUp(node);
      return p;   
};

vector3df GetPointBelow(ISceneNode* node, float distance)     
{   
      vector3df p = node->getPosition();
      p -= distance * GetIrrUp(node);
      return p;   
};
 
vector3df GetPointInFrontAndAbove(ISceneNode* node,float d, float u)   
{   
   vector3df p = GetPointInFront(node,d);
   p.Y = GetPointAbove(node,u).Y;
   return p;     
};

vector3df GetPointInBackAndAbove(ISceneNode* node,float d, float u)   
{   
   vector3df p = GetPointInBack(node,d);
   p.Y = GetPointAbove(node,u).Y;
   return p;     
};

class MyEventReceiver : public IEventReceiver
{
public:
   // This is the one method that we have to implement
   virtual bool OnEvent(const SEvent& event)
   {
      // Remember whether each key is down or up
      if (event.EventType == irr::EET_KEY_INPUT_EVENT)
         KeyIsDown[event.KeyInput.Key] = event.KeyInput.PressedDown;

      return false;
   }

   // This is used to check whether a key is being held down
   virtual bool IsKeyDown(EKEY_CODE keyCode) const
   {
      return KeyIsDown[keyCode];
   }
   
   MyEventReceiver()
   {
      for (u32 i=0; i<KEY_KEY_CODES_COUNT; ++i)
         KeyIsDown[i] = false;
   }

private:
   // We use this array to store the current state of each key
   bool KeyIsDown[KEY_KEY_CODES_COUNT];
};


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>(1000, 700), 16, false, false, false, &receiver);

   if (device == 0)
      return 1; // could not create selected driver.

   video::IVideoDriver* driver = device->getVideoDriver();
   scene::ISceneManager* smgr = device->getSceneManager();

   IAnimatedMesh* usership = smgr->getMesh("C:/Users/Jordan/Documents/Visual Studio 2010/Projects/irrlichttest/Debug/Space_Ship_23.3DS");
   if (!usership)
   {
      device->drop();
      return 1;
   }
   IAnimatedMeshSceneNode* node = smgr->addAnimatedMeshSceneNode(usership);

   if (node)
   {
      node->setMaterialFlag(EMF_LIGHTING, false);
      node->setMaterialTexture( 0, driver->getTexture("C:/Users/Jordan/Documents/Visual Studio 2010/Projects/irrlichttest/Debug/Ship_23_Texmap.png") );
      node->setScale(core::vector3df(.1f,.1f,.1f));
   }

   IAnimatedMesh* planeback = smgr->getMesh("C:/Users/Jordan/Documents/Visual Studio 2010/Projects/irrlichttest/Debug/plane.3DS");
   if (!planeback)
   {
      device->drop();
      return 1;
   }
   IAnimatedMeshSceneNode* planeNode = smgr->addAnimatedMeshSceneNode(planeback);

   if (planeNode)
   {
      planeNode->setMaterialFlag(EMF_LIGHTING, false);
      planeNode->setMaterialTexture( 0, driver->getTexture("C:/Users/Jordan/Documents/Visual Studio 2010/Projects/irrlichttest/Debug/Spacescape.jpg") );

      planeNode->setScale(core::vector3df(30.f,30.f,30.f));
   }


   ISceneNode* plane = smgr->addSkyBoxSceneNode(
        driver->getTexture("C:/Users/Jordan/Documents/Visual Studio 2010/Projects/irrlichttest/Debug/Spacescape.jpg"),
        driver->getTexture("C:/Users/Jordan/Documents/Visual Studio 2010/Projects/irrlichttest/Debug/Spacescape.jpg"),
        driver->getTexture("C:/Users/Jordan/Documents/Visual Studio 2010/Projects/irrlichttest/Debug/Spacescape.jpg"),
        driver->getTexture("C:/Users/Jordan/Documents/Visual Studio 2010/Projects/irrlichttest/Debug/Spacescape.jpg"),
        driver->getTexture("C:/Users/Jordan/Documents/Visual Studio 2010/Projects/irrlichttest/Debug/Spacescape.jpg"),
        driver->getTexture("C:/Users/Jordan/Documents/Visual Studio 2010/Projects/irrlichttest/Debug/Spacescape.jpg"));;

   //partical system
   scene::IParticleSystemSceneNode* ps = smgr->addParticleSystemSceneNode();

    scene::IParticleEmitter* em = ps->createBoxEmitter(
        core::aabbox3d<f32>(2,2,2,2,2,2), // emitter size
        core::vector3df(0.08f,0.00f,0.0f),   // initial direction
        80,100,                             // emit rate
        video::SColor(0,255,255,255),       // darkest color
        video::SColor(0,255,255,255),       // brightest color
        800,2000,90,                         // min and max age, angle
        core::dimension2df(1.f,1.f),         // min size
        core::dimension2df(2.f,2.f));        // max size

    ps->setEmitter(em); // this grabs the emitter
    em->drop(); // so we can drop it here without deleting it

    scene::IParticleAffector* paf = ps->createFadeOutParticleAffector();

    ps->addAffector(paf); // same goes for the affector
    paf->drop();

    ps->setPosition(core::vector3df(-70,60,40));
    ps->setScale(core::vector3df(2,2,2));
    ps->setMaterialFlag(video::EMF_LIGHTING, false);
    ps->setMaterialFlag(video::EMF_ZWRITE_ENABLE, false);
    ps->setMaterialTexture(0, driver->getTexture("C:/Users/Jordan/Documents/Visual Studio 2010/Projects/irrlichttest/Debug/fire.bmp"));
    ps->setMaterialType(video::EMT_TRANSPARENT_VERTEX_ALPHA);

   //load camera at the right distance from the model and remove cursor
   ICameraSceneNode* camera = smgr->addCameraSceneNode(0, vector3df(-50,60,50));
   device->getCursorControl()->setVisible(false);

   
   int lastFPS = -1;

   u32 then = device->getTimer()->getTime();

   // This is the movemen speed in units per second.
   const f32 MOVEMENT_SPEED = 1.f;
   const f32 ROTATION_SPEED = 100.f;
   const f32 ROTATION_SPEED2 = -100.f;
   const f32 MAX_THRUST     = 6.f;
   const f32 MIN_THRUST     = 0.f;

   const f32 CAMERA_BACK    = 500.0;
   const f32 CAMERA_UP      = 500.0;

   float thrust = 0;
   float rotat = ROTATION_SPEED;
   float rotat2 = 0;

   int a = 0;
   vector3df rotation = node->getRotation();
   vector3df nodePos = GetIrrIn(node);
   vector3df movingVector;
   

   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;

      // thrust
      if(receiver.IsKeyDown(irr::KEY_KEY_W)) 
      {
              if (thrust == 0)
              {
                  //take this out of the if and else statments and put the if and else in comments and the drift code will work. 
                  //this bit of code was my atempt to make it not jump when you press w but the rotation of the old vector is messed lol
                  nodePos = GetIrrIn(node);
              }
              else
              {
                  if (a = 5 && nodePos != GetIrrIn(node))
                  {
                      movingVector = nodePos;
                      movingVector.X += 0.1;
                      nodePos = movingVector;
                  }
                  else
                  {
                      a = 0;
                  }
              }

              thrust += MOVEMENT_SPEED * frameDeltaTime;
      }
      if(receiver.IsKeyDown(irr::KEY_KEY_S)) 
      {
          thrust -= MOVEMENT_SPEED * frameDeltaTime;
      }
     
      // rotate node left / right
      if(receiver.IsKeyDown(irr::KEY_KEY_A)) 
      {
          //rotat = ROTATION_SPEED2 * frameDeltaTime;
            rotat2 = ROTATION_SPEED2 * frameDeltaTime;
            a = 5;
      }
      else if (!(receiver.IsKeyDown(KEY_KEY_D)))
      {
          rotat2 = 0;
          rotat = 0;
      }
      if(receiver.IsKeyDown(irr::KEY_KEY_D)) 
      {
          rotat = ROTATION_SPEED * frameDeltaTime;
      }
      else if (!(receiver.IsKeyDown(KEY_KEY_A)))
      {
          rotat = 0;
      }
     
      // tilt up / down
      if(receiver.IsKeyDown(irr::KEY_KEY_Z)) 
      {
          rotation.X -= ROTATION_SPEED * frameDeltaTime;
          node->setRotation(rotation);
      }
      if(receiver.IsKeyDown(irr::KEY_KEY_X))
      {
          rotation.X += ROTATION_SPEED * frameDeltaTime;
          node->setRotation(rotation);
      }
      

      
      //if trust goes over max thrust then set it to max thrust. if trust goes below min trust. set trust to min thrust
      if (thrust > MAX_THRUST) thrust = MAX_THRUST; 
      if (thrust < MIN_THRUST) thrust = MIN_THRUST;

      // set the nodes rotation / position
      node->setRotation(node->getRotation() + GetIrrUp(node) * rotat);
      node->setRotation(node->getRotation() + GetIrrUp(node) * rotat2);
      node->setPosition(node->getPosition() + nodePos * thrust);
      camera->setPosition(camera->getPosition() + nodePos * thrust);

      /*Set camera to look at node*/
      camera->setTarget(node->getPosition());

      driver->beginScene(true, true, video::SColor(255,113,113,133));

      smgr->drawAll(); // draw the 3d scene
      device->getGUIEnvironment()->drawAll(); // draw the gui environment (the l

      driver->endScene();

      int fps = driver->getFPS();

      if (lastFPS != fps)
      {
         core::stringw tmp(L"Movement Example - Irrlicht Engine [");
         tmp += driver->getName();
         tmp += L"] fps: ";
         tmp += fps;

         device->setWindowCaption(tmp.c_str());
         lastFPS = fps;
      }
   }

   /*
   In the end, delete the Irrlicht device.
   */
   device->drop();
   
   return 0;
}

/*
That's it. Compile and play around with the program.
**/

you will obvously need to change the models and stuff so it works. send me a message if you want the models i have.

thanks
Jordan