//This method does all the work for the brush. Every time the mouse moves this will be called for each brush on the surface of the model.
Bool ExampleSculptGrabBrush::MovePointsFunc(BrushDabData* dab)
{
PolygonObject* polyObj = dab->GetPolygonObject();
if (!polyObj)
return false;
Int32 a;
//Get the world matrix for the model so that we can turn local coordinates into world coordinates.
Matrix mat = polyObj->GetMg();
//Get the location of the hitpoint on the model in world coordinates
Vector hitPointWorld = mat * dab->GetHitPoint();
//Zero out the offset since its no longer required
mat.off = Vector(0, 0, 0);
const BaseContainer* pData = dab->GetData();
//Get our custom direction value that we added to our .res file.
Int32 dirMode = pData->GetInt32(MDATA_TOOLSCULPTGRABBRUSH_DIRMODE);
//Find the distance the mouse has moved in world coordinates by getting the world position of the mouse and subtracting the current grab brush world coordinate
Vector moveAmnt = (dab->GetMousePos3D() - hitPointWorld);
//Transform this distance into a vector that is in the local coordinates of the model.
moveAmnt = ~mat * moveAmnt;
Vector normal = dab->GetNormal();
switch (dirMode)
{
case MDATA_TOOLSCULPTGRABBRUSH_DIRMODE_NORMAL:
{
//If we are moving the point in the direction of its normal then use the length of the distance vector to scale the normal.
moveAmnt = normal * moveAmnt.GetLength();
//Adjust the direction of the vector depending on if its moving above the surface or below it.
Float dot = Dot(normal, moveAmnt);
if (dot < 0)
moveAmnt *= -1;
break;
}
case MDATA_TOOLSCULPTGRABBRUSH_DIRMODE_MOUSEDIR:
default:
//Nothing to do here since moveAmnt is already correct.
break;
}
//Get the original points on the surface of the object. These points are the state of the object when the
//user first clicks on the model to do a mouse stroke. This allows you to compare where the points are during
//a stroke, since you have moved them, when the original positions.
const Vector32* pOriginalPoints = dab->GetOriginalPoints();
Int32 pointCount = dab->GetPointCount();
const Vector* pPoints = dab->GetPoints();
const BrushPointData* pPointData = dab->GetPointData();
//If any of the symmetry settings have been enabled, and this is a symmetry stroke instance, then this will return true.
Bool mirror = dab->IsMirroredDab();
//Loop over every point on the dab and move them by the moveAmnt.
for (a = 0; a < pointCount; ++a)
{
Int32 pointIndex = pPointData[a].pointIndex;
//Get the falloff value for this point. This value will take into account the current stencil, stamp settings and the falloff curve to create this value.
Float fallOff = dab->GetBrushFalloff(a);
//Get the original location for this point
Vector original = (Vector64)pOriginalPoints[pointIndex];
//Get the vector of the point we are going to change.
const Vector& currentPoint = pPoints[pointIndex];
//If the user has any of the symmetry settings enabled and this is one of the symmetrical brush instance then mirror will be True.
//We can check to see if another brush instance has already touched this point and moved it by calling the IsPointModified method.
//If a point has been touched then that means it has already been moved by a certain vector by that brush instance.
//This happens when the brushes overlap the same area of the model, which can easily happen if you have a large brush size and are using symmetry.
//So we just offset it by another vector and do not worry about the original location of the point.
if (mirror && dab->IsPointModified(pointIndex))
{
//Adjust the offset by the new amount.
dab->OffsetPoint(pointIndex, moveAmnt * fallOff);
}
else
{
//If there is no symmetry or the point hasn't been touched then we can just set the position of the point normally.
//First determine the offset vector by using the original location of the point and adding on the new point after it has been adjusted by the falloff value.
Vector newPosOffset = original + moveAmnt * fallOff;
//A new offset is calculated by using this new point and its current position.
Vector offset = newPosOffset - currentPoint;
//Offset the point to place it in the correct location.
dab->OffsetPoint(pointIndex, offset);
}
}
//Ensure that all the points for the dab are marked as dirty. This is required to ensure that they all update even if they were not directly
//touched by this brush instance. Marking all points as dirty ensures that the normals for all points are updated. This is only required
//for grab brushes when multiple brush instances are touching the same points.
dab->DirtyAllPoints(SCULPTBRUSHDATATYPE_POINT);
return true;
}
