Sign in to follow this  
Anand Baumunk

Picking in objectspace

Recommended Posts

Hello, I got some problems with the picking of objects.
I got this code to compute the pickray and then transform it into objectspace:

[CODE]
void createPickray(int mouseX, int mouseY){
float pointX, pointY;

windowW = 1024 - 16; //1008;
windowH = 768 - 38; //730;
// Move the mouse cursor coordinates into the -1 to +1 range.
pointX = ((2.0f * (float)mouseX) / (float)windowW) - 1.0f;
pointY = (((2.0f * (float)mouseY) / (float)windowH) - 1.0f) * -1.0f;

// Adjust the points using the projection matrix to account for the aspect ratio of the viewport.
projectionMatrix = cam1->getcamprojm();
pointX = pointX / projectionMatrix._11;
pointY = pointY / projectionMatrix._22;
// Get the inverse of the view matrix.
viewMatrix = cam1->getcamviewm();
D3DXMatrixInverse(&inverseViewMatrix, NULL, &viewMatrix);
// Calculate the direction of the picking ray in view space.
direction.x = (pointX * inverseViewMatrix._11) + (pointY * inverseViewMatrix._21) + inverseViewMatrix._31;
direction.y = (pointX * inverseViewMatrix._12) + (pointY * inverseViewMatrix._22) + inverseViewMatrix._32;
direction.z = (pointX * inverseViewMatrix._13) + (pointY * inverseViewMatrix._23) + inverseViewMatrix._33;
// Get the origin of the picking ray which is the position of the camera.
origin = cam1->getpos();

}


// To objectspace:

void Pick(D3DXVECTOR3 origin, D3DXVECTOR3 direction){
D3DXMATRIX inverseWorldMatrix;
D3DXVECTOR3 rayOrigin, rayDirection;
// Now get the inverse of the translated world matrix.
D3DXMatrixInverse(&inverseWorldMatrix, NULL, &World);
// Now transform the ray origin and the ray direction from view space to world space.
D3DXVec3TransformCoord(&rayOrigin, &origin, &inverseWorldMatrix);
D3DXVec3TransformNormal(&rayDirection, &direction, &inverseWorldMatrix);
// Normalize the ray direction.
D3DXVec3Normalize(&rayDirection, &rayDirection);

}


[/CODE]

When using this on an object with default worldmatrix, everything runs just fine. But in any different worldmatrix, it completly messes up.
After some further investigation: The Scaling part runs fine, only translation and rotation are not applied, even when I use only them.
Can someone tell me whats wrong here? Edited by gnomgrol

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this