What I am trying to do is output some code when I mouse over one of my meshes on the screen. It seems to be very accurate when I have a mesh close to my camera. As my camera moves away from the mesh it becomes less and less accurate. I am moving away in the z direction both the camera position and it's look at position.
Sounds like to me it has something to do with my projection matrix, but I can't see the problem. Or is this inaccuracy common when moving away from meshes?
Here is the function. I pass in the mouse X/Y pos, get the ray, then see if it intersects with any of my meshes.
D3DXVECTOR3 * World::checkForMeshHit(long mouseX, long mouseY){
D3DXMATRIX matProjection, matView, matWorld, matInverse;
LPDIRECT3DDEVICE9 * d3ddev = d3d->getD3ddev();
(*d3ddev)->GetTransform(D3DTS_PROJECTION, &matProjection);
(*d3ddev)->GetTransform(D3DTS_VIEW, &matView);
float xAngle = (((2.0f * mouseX) / d3d->getScreenWidth()) - 1.0f) / matProjection._11;
float yAngle = (((-2.0f * mouseY) / d3d->getScreenHeight()) + 1.0f) / matProjection._22;
D3DXVECTOR3 * direction = new D3DXVECTOR3(xAngle, yAngle, 1.0f);
for(int i = 0; i < units.size(); i++){
BOOL hit = false;
direction = new D3DXVECTOR3(xAngle, yAngle, 1.0f);
D3DXVECTOR3 origin = D3DXVECTOR3(0.0f, 0.0f, 0.0f);
EnemyUnit * unit = units;
matWorld = (*unit->getMeshModel()->getWorldMat());
D3DXMatrixInverse(&matInverse, NULL, &(matWorld*matView));
D3DXVec3TransformCoord(&origin, &origin, &matInverse);
D3DXVec3TransformNormal(direction, direction, &matInverse);
D3DXVec3Normalize(direction, direction);
D3DXIntersect(unit->getMeshModel()->getMesh(), &origin, direction, &hit, NULL, NULL, NULL, NULL, NULL, NULL);
if(hit){
cout << "says its mousing over the object " << endl;
break;
}
}
return NULL;
}
Here is initial camera code if that matters.
void D3DCreator::setupCamera(void){
D3DXMATRIX matView; // the view transform matrix
D3DXMatrixLookAtLH(&matView,
&D3DXVECTOR3 (cameraPosX, cameraPosY, cameraPosZ), // the camera position
&D3DXVECTOR3 (cameraLookAtX, cameraLookAtY, cameraLookAtZ), // the look-at position
&D3DXVECTOR3 (0.0f, 1.0f, 0.0f)); // the up direction
d3ddev->SetTransform(D3DTS_VIEW, &matView); // set the view transform to matView
// set the projection transform
D3DXMATRIX matProjection; // the projection transform matrix
D3DXMatrixPerspectiveFovLH(&matProjection,
D3DXToRadian(45), // the horizontal field of view
(FLOAT)SCREEN_WIDTH / (FLOAT)SCREEN_HEIGHT, // aspect ratio
1.0f, // the near view-plane
100.0f); // the far view-plane
d3ddev->SetTransform(D3DTS_PROJECTION, &matProjection); // set the projection
}
