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Hunter_Ex

Ray picking SOLVED

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ASPECT = 1.333333 ANGLE = 45 sx = 2d mouse position x (int) sy = 2d mouse position y (int) the result i get only affects when i move the camera and when i move the mouse in the view nothing but the 4 last deciamls change the code is bad but its my first attempt to ray picking iknow that i use the y compnent of the camera pos and view to z becouse i change back when i get the result
FLOAT screenx,screeny;
   screenx = (float)sx;
   screeny = (float)sy;
    
            
   D3DXVECTOR3 res;
   D3DXVECTOR3 vD,vU,vV;
   FLOAT fov,comp;
   
   vD.x = (View.x - Pos.x);
   vD.y = (View.z - Pos.z);
   vD.z = (View.y - Pos.y);
   D3DXVec3Normalize(&vD,&vD);

   vU.x = Up.x;
   vU.y = Up.z;
   vU.z = Up.y;
   
   comp = vU.x*vD.x + vU.y*vD.y + vU.z*vD.z;
   vU -= comp * vD;
   D3DXVec3Normalize(&vU,&vU);
   
   fov = tanf(ANGLE*D3DX_PI/360.0f);
   vU *= fov;
   
   vV.x = vU.y*vD.z-vD.y*vU.z;  
   vV.y = vU.z*vD.x-vD.z*vU.x;
   vV.z = vU.x*vD.y-vD.x*vU.y; 
   vV *= ASPECT;
   
   FLOAT w,h;
   FLOAT mx,my,mz;
   w = 2.0f*screenx/800.0f-1.0f;
   h = 1.0f-2.0f*screeny/600.0f;
   mx = (vD.x+vU.x)*h+vV.x*w;
   my = (vD.y+vU.y)*h+vV.y*w;
   mz = (vD.z+vU.z)*h+vV.z*w;
   
   res.x = (Pos.x - Pos.y) * mx / mz;
   res.y = (Pos.z - Pos.y) * my / mz;
   res.z = 1;
   
   return res;


do anyone know a sulution to a better code or link me to a page thx Hunter Ex [Edited by - Hunter_Ex on August 8, 2005 4:48:01 PM]

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thx : D

how comes id miss that function : /

but know im a little lost how will the ray be??

can someone just point me in the right direction of using this function ( D3DXVec3Unproject )
so i not waste more time than already did :D

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D3DXVECTOR3 vMouse;
D3DXVECTOR3 vMousePos3D;
D3DXVECTOR3 vCamPos = camera.position;
D3DVIEWPORT9 viewport;
D3DXMATRIX matView, matWorld, matProj;

mouse.x = (float)sx;
mouse.y = (float)sy;
mouse.z = 1.0f;

//Get the viewport
device->GetViewport(&viewport);

//Get the transform matrices
device->GetTransform(D3DTS_WORLD, &matWorld);
device->GetTransform(D3DTS_VIEW, &matView);
device->GetTransform(D3DTS_PROJECTION, &matProj);

//Unproject the mouse position from 2D screen space into 3D world space
D3DXVec3Unproject(&vMousePos3D, &vMouse, &viewport, &matProj, &matView, &matWorld);

//Subtract the 3D mouse position from the camera position to get direction and magnitude
D3DXVECTOR3 temp = vMousePos3D - vCamPos;

//Normalize the vector to get just direction
D3DXVECTOR3 vRayDirection;
D3DXVec3Normalize(&vRayDirection, &temp);

//Construct a ray that goes from your camera through the mouse which you can use for picking
Ray ret; //I'm assuming that you have a ray class with start vector and direction
ret.start = vCamPos;
ret.direction = vRaydirection;

return ret;


I'm just coding off the top of my head here, so it might have some errors in it. There's a few lines of implementation specific code and lots of room for optimizations. The biggest potential optimization is using a software copy of the 3 transforms and the viewport so you don't have to query the D3D device driver all the time.

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thx alot all i really wondered about was the viewport but know i know how to get it and yes i will use the predefined world matrices and i have an ray class ; )

thx again

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