UVWTag Manual

About

A UVWTag stores UVW coordinates for a (polygon) object. For each polygon a set of four UVW coordinates is stored (UVWStruct). The class UVWTag is based on VariableTag so the typical workflows on handling tags apply, see BaseTag and VariableTag Manual.

UVWTag objects are an instance of Tuvw.

Access

A UVWTag is typically attached to a polygon object.

Note
A polygon object can host multiple UVW tags.

Allocation/Deallocation

UVWTag instances are created with the usual tools.

A UVW tag with projection-based UVs can be created with:

// This example checks if the given object hosts a UVW tag.
// If not, a UVW tag is created.
BaseTag* const foundTag = object->GetTag(Tuvw);
UVWTag* uvwTag = static_cast<UVWTag*>(foundTag);
if (uvwTag == nullptr)
{
// check if the given object is a polygon object
if (object->IsInstanceOf(Opolygon))
{
PolygonObject* const polyObject = static_cast<PolygonObject*>(object);
const Int32 polyCount = polyObject->GetPolygonCount();
uvwTag = UVWTag::Alloc(polyCount);
if (uvwTag == nullptr)
return maxon::OutOfMemoryError(MAXON_SOURCE_LOCATION);
polyObject->InsertTag(uvwTag);
}
}
PyObject * object
Definition: asdl.h:7
void InsertTag(BaseTag *tp, BaseTag *pred=nullptr)
Definition: c4d_basetag.h:47
Definition: c4d_baseobject.h:1619
Int32 GetPolygonCount(void) const
Definition: c4d_baseobject.h:1773
Definition: c4d_basetag.h:380
static UVWTag * Alloc(Int32 count)
maxon::Int32 Int32
Definition: ge_sys_math.h:60
#define Opolygon
Polygon - PolygonObject.
Definition: ge_prepass.h:1024
#define MAXON_SOURCE_LOCATION
Definition: memoryallocationbase.h:67
#define Tuvw
UVW data - UVWTag.
Definition: ge_prepass.h:1389
Definition: object.h:105

Access Data

There are two ways to edit the data stored inside a UVWTag. The "slow" way is to access every set of UVW coordinate independently. The "fast" way works with a data handle that allows direct access to the internal memory.

Slow

The UVW coordinates stored in a UVWTag can be accessed with:

// This example loops through the UVW data stored in the given UVW tag.
const Int32 count = uvwTag->GetDataCount();
for (Int32 i = 0; i < count; ++i)
{
const UVWStruct uvwData = uvwTag->GetSlow(i);
}
Py_ssize_t i
Definition: abstract.h:645
Py_ssize_t count
Definition: abstract.h:640
static String IntToString(Int32 v)
Definition: c4d_string.h:495
static String VectorToString(const Vector32 &v, Int32 nnk=-1)
Definition: c4d_string.h:571
UVWStruct GetSlow(Int32 i)
Definition: c4d_basetag.h:412
Int32 GetDataCount(void) const
#define ApplicationOutput(formatString,...)
Definition: debugdiagnostics.h:210
Definition: operatingsystem.h:473
Vector c
The UVW coordinate for the third point.
Definition: operatingsystem.h:512
Vector b
The UVW coordinate for the second point.
Definition: operatingsystem.h:511
Vector a
The UVW coordinate for the first point.
Definition: operatingsystem.h:510
Vector d
The UVW coordinate for the fourth point.
Definition: operatingsystem.h:513

Fast

The fast access to the UVW coordinates stored in the UVWTag is provided by a data handle and static functions:

// This example calculates UVW coordinates based on the polygon's world space position.
UVWHandle handle = uvwTag->GetDataAddressW();
const Int32 count = uvwTag->GetDataCount();
for (Int32 i = 0; i < count; ++i)
{
UVWStruct uvwData;
// get points in world space
CPolygon polygon = polygons[i];
const Vector a = mg * points[polygon.a];
const Vector b = mg * points[polygon.b];
const Vector c = mg * points[polygon.c];
const Vector d = mg * points[polygon.d];
// define UV coordinates based on the world space position
// CalculateUVCoordinates() is a custom function
CalculateUVCoordinates(a, uvwData.a);
CalculateUVCoordinates(b, uvwData.b);
CalculateUVCoordinates(c, uvwData.c);
CalculateUVCoordinates(d, uvwData.d);
UVWTag::Set(handle, i, uvwData);
}
polyObject->Message(MSG_UPDATE);
Bool Message(Int32 type, void *data=nullptr)
Definition: c4d_baselist.h:1437
static void Set(UVWHandle dataptr, Int32 i, const UVWStruct &s)
Definition: c4d_basetag.h:496
UVWHandle GetDataAddressW(void)
Py_UNICODE c
Definition: unicodeobject.h:1200
#define MSG_UPDATE
Must be sent if the bounding box has to be recalculated. (Otherwise use MSG_CHANGE....
Definition: c4d_baselist.h:341
void * UVWHandle
Handle for UVW data. See also: UVWTag.
Definition: operatingsystem.h:461
Represents a polygon that can be either a triangle or a quadrangle.
Definition: c4d_baseobject.h:44
Int32 d
Index of the fourth point in the polygon.
Definition: c4d_baseobject.h:48
Int32 b
Index of the second point in the polygon.
Definition: c4d_baseobject.h:46
Int32 c
Index of the third point in the polygon.
Definition: c4d_baseobject.h:47
Int32 a
Index of the first point in the polygon.
Definition: c4d_baseobject.h:45

Pin

Pin are stored by UV tag, you can access them with:

// This example sets the current active Point Selection to the UV Point pinned.
// Get object
BaseObject* const obj = doc->GetActiveObject();
if (obj == nullptr || ! obj->IsInstanceOf(Opoint))
return maxon::IllegalArgumentError(MAXON_SOURCE_LOCATION, "Should be a Point Object"_s);
// Retrieves the fist uvwtag
UVWTag* uvTag = static_cast<UVWTag*>(obj->GetTag(Tuvw));
if (uvTag == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
// Retrieves the Pin Selection Stored in the uvTag
const BaseSelect& pinSelection = uvTag->GetPinSelection();
if (pinSelection.GetCount() == 0)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
// Retrieves the current Point Selection stored in the PointObject
BaseSelect* ptSelect = ToPoint(obj)->GetPointS();
if (ptSelect == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
ptSelect->DeselectAll();
// Convert UV Point baseSelect to PointObject BaseSelect
// UV Points are indexed by 4 * polygon + point where @c polygon is the polygon index and c point is the point index between 0 and 3 (a, b, c, d).
const CPolygon* polys = ToPoly(obj)->GetPolygonR();
Int32 seg = 0, smin, smax, idx;
while (pinSelection.GetRange(seg++, LIMIT<Int32>::MAX, &smin, &smax))
{
// For each sequance of range
for (idx = smin; idx <= smax; idx++)
{
// Retrieves the polygon ID and the Cpolygon ID
Int32 polyId = idx / 4;
Int32 cpolyPtId = idx % 4;
// Retrieve the real PtID from the Cpolygon
Int32 ptId = polys[polyId][cpolyPtId];
ptSelect->Select(ptId);
}
}
#define ToPoint(op)
Casts a BaseObject* to a PointObject*.
Definition: c4d_baseobject.h:2192
#define ToPoly(op)
Casts a BaseObject* to a PolygonObject*.
Definition: c4d_baseobject.h:2195
void EventAdd(EVENT eventflag=EVENT::NONE)
Definition: c4d_baseobject.h:225
Definition: c4d_baseselect.h:32
Bool DeselectAll(void)
Bool Select(Int32 num)
Int32 GetCount(void) const
Bool GetRange(Int32 seg, Int32 maxElements, Int32 *a, Int32 *b) const
Definition: apibasemath.h:34
BaseSelect & GetPinSelection()
Definition: c4d_basetag.h:528
PyObject * obj
Definition: complexobject.h:60
#define Opoint
Point - PointObject.
Definition: ge_prepass.h:1073
const char * doc
Definition: pyerrors.h:226
// This example sets the UV Point pinned to the current active Point Selection.
// Get object
BaseObject* const obj = doc->GetActiveObject();
if (obj == nullptr || ! obj->IsInstanceOf(Opoint))
return maxon::IllegalArgumentError(MAXON_SOURCE_LOCATION, "Should be a Point Object"_s);
// Retrieves the fist uvwtag
UVWTag* uvTag = static_cast<UVWTag*>(obj->GetTag(Tuvw));
if (uvTag == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
// Retrieves the current Point Selection stored in the PointObject
BaseSelect* ptSelect = ToPoint(obj)->GetPointS();
if (ptSelect == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
// Allocate a new pinSelection To Set
// Convert PointObject BaseSelect to Uv Point baseSelect
// UV Points are indexed by 4 * polygon + point where c polygon is the polygon index and c point is the point index between 0 and 3 (a, b, c, d).
// Retrieves the read array of all Cpolygon
const CPolygon* poly = ToPoly(obj)->GetPolygonR();
if (poly == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
// Retrieves an array of the selection state
const maxon::AutoMem<UChar> ptArray = ptSelect->ToArray(ToPoint(obj)->GetPointCount());
if (ptArray == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
for (Int32 i = 0; i < ToPoly(obj)->GetPolygonCount(); ++i)
{
const CPolygon* pp = poly + i;
if (pp == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
if (ptArray[pp->a])
pinsToSet->Select(i * 4 + 0);
if (ptArray[pp->b])
pinsToSet->Select(i * 4 + 1);
if (ptArray[pp->c])
pinsToSet->Select(i * 4 + 2);
if (ptArray[pp->d])
pinsToSet->Select(i * 4 + 3);
}
// Clears the current Pin Selection
// Adds the built selection to the current pin selection
uvTag->AddToPinSelection(pinsToSet);
Definition: ge_autoptr.h:37
UChar * ToArray(Int32 count) const
void ClearPinSelection()
Clears the pin point selection for this tag.
Definition: c4d_basetag.h:515
Bool AddToPinSelection(const BaseSelect &pinSelection)
Definition: c4d_basetag.h:541
Definition: baseref.h:62
// This example removes from the UV Point pinned, the current active Point Selection.
// Get object
BaseObject* const obj = doc->GetActiveObject();
if (obj == nullptr || ! obj->IsInstanceOf(Opoint))
return maxon::IllegalArgumentError(MAXON_SOURCE_LOCATION, "Should be a Point Object"_s);
// Retrieves the fist uvwtag
UVWTag* uvTag = static_cast<UVWTag*>(obj->GetTag(Tuvw));
if (uvTag == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
// Retrieves the current Point Selection stored in the PointObject
BaseSelect* ptSelect = ToPoint(obj)->GetPointS();
if (ptSelect == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
// Allocate a new pinSelection To Set
// Convert PointObject BaseSelect to Uv Point baseSelect
// UV Points are indexed by 4 * polygon + point where c polygon is the polygon index and c point is the point index between 0 and 3 (a, b, c, d).
// Retrieves the read array of all Cpolygon
const CPolygon* poly = ToPoly(obj)->GetPolygonR();
if (poly == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
// Retrieves an array of the selection state
const maxon::AutoMem<UChar> ptArray = ptSelect->ToArray(ToPoint(obj)->GetPointCount());
if (ptArray == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
for (Int32 i = 0; i < ToPoly(obj)->GetPolygonCount(); ++i)
{
const CPolygon* pp = poly + i;
if (pp == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
if (ptArray[pp->a])
pinsToSet->Select(i * 4 + 0);
if (ptArray[pp->b])
pinsToSet->Select(i * 4 + 1);
if (ptArray[pp->c])
pinsToSet->Select(i * 4 + 2);
if (ptArray[pp->d])
pinsToSet->Select(i * 4 + 3);
}
// Removes the built selection to the current pin selection
uvTag->RemoveFromPinSelection(pinsToSet);
Bool RemoveFromPinSelection(const BaseSelect &pinSelection)
Definition: c4d_basetag.h:549

While it's not stored directly in the UVWTag you may need to retrieve UV seems of an object:

// This example select edge corresponding to the UV seams of the current object
// Gets object
BaseObject* const obj = doc->GetActiveObject();
if (obj == nullptr || ! obj->IsInstanceOf(Opoint))
return maxon::IllegalArgumentError(MAXON_SOURCE_LOCATION, "Should be a Point Object"_s);
const EdgeBaseSelect* uvSeams = GetUVSeams(obj);
if (uvSeams == nullptr || uvSeams->GetCount() == 0)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
// Retrieves the current Edge Selection stored in the Polygon Object
BaseSelect* edgeSelect = ToPoly(obj)->GetEdgeS();
if (edgeSelect == nullptr)
return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
// Deselect all the currently selected edge
edgeSelect->DeselectAll();
// Copies the UV seams to the Polygon Edge selection.
uvSeams->CopyTo(edgeSelect);
const EdgeBaseSelect * GetUVSeams(const BaseObject *obj)
Bool CopyTo(BaseSelect *dest) const
Definition: c4d_baseselect.h:317

Further Reading