Vector4 Transforms::screenSpaceToNDCSpace(const Point& screenPoint) {
CSize screenDimensions = GraphicsInterface::screenSize();
Vector4 screenSize = Vector4((float)screenDimensions.width, (float)screenDimensions.height, 0, 0);
Vector4 screenSpace((float)screenPoint.x, (float)screenPoint.y, 0, 1);
Vector4 ndcSpace = screenSpace / screenSize;
ndcSpace.y = 1.0f - ndcSpace.y;
ndcSpace = ndcSpace * 2.0f - 1.0f;
ndcSpace.z = screenPoint.z;
ndcSpace.w = 1;
return ndcSpace;
}
// Project the mouse cursor from screen space to object space
void EditExt::ProjectScreenToWorld(D3DXVECTOR3* pOut, float screenX, float screenY, float worldZ)
{
D3DXVECTOR3 lineBegin, lineEnd;
// Unproject the near and far points given by the screen X,Y coords
D3DXVECTOR3 screenSpace(screenX, screenY, 0.0f);
D3DXVec3Unproject(&lineBegin, &screenSpace, &viewport, &projection_matrix, &view_matrix, &worldMatrix);
screenSpace.z = 1.0f;
D3DXVec3Unproject(&lineEnd, &screenSpace, &viewport, &projection_matrix, &view_matrix, &worldMatrix);
// Using a plane intersection, we can determine the object space coordinates of the screen space coords
// at a certain Z depth, intersecting the line given above.
orig.z = worldZ;
D3DXPlaneFromPointNormal(&plane, &orig, &normal);
D3DXPlaneIntersectLine(pOut, &plane, &lineBegin, &lineEnd);
}
Vector4 Transforms::screenSpaceToViewSpace(const Matrix4x4& projInv, const Point& screenPoint) {
CSize screenDimensions = GraphicsInterface::screenSize();
Vector4 screenSize = Vector4((float)screenDimensions.width, (float)screenDimensions.height, 0, 0);
Vector4 screenSpace((float)screenPoint.x, (float)screenPoint.y, 0, 1);
Vector4 ndcSpace = screenSpace / screenSize;
ndcSpace.y = 1.0f - ndcSpace.y;
ndcSpace = ndcSpace * 2.0f - 1.0f;
ndcSpace.z = screenPoint.z;
ndcSpace.w = 1;
Vector4 viewSpace = projInv * ndcSpace;
viewSpace /= viewSpace.w;
return viewSpace;
}