On 11/01/2015 at 12:12, xxxxxxxx wrote:
Cinema 4D Version: R16
Platform: Windows ;
So I'm transitioning a completed python plugin to C++ and C++ doesn't have easy to use dictionaries like Python. Or at least know that Maxon recommends I use in their best coding practices. That's fine, I can use a BaseArray. The question is how does one initialize a BaseArray with a set of known values. A second part to that would be how I might use a resource of some sort to load a BaseArray with values.
On 11/01/2015 at 13:57, xxxxxxxx wrote:
In C++ dictionaries are called maps.
These are the R14 examples I have in my notes.
I haven't used these in R16 yet. So the code might need to written slightly different. But hopefully it will give you a quick boost in using them.
//The HashMap array in R14++ is similar to a dictionary
//Each array element has a key, and a value
//The key can be used to look up the elements in the array. Instead of using element index numbers
//The key and value types must bet set up when creating the HM: maxon::HashMap<type, type> myHmap;
//NOTE: You can use HM->put to add new items to the array if you don't want to check if an entry already exists
maxon::HashMap<Int, String> myHmap;
auto entry1 = myHmap.Put(1, "first"); // 1 is the key "first" is the value
auto entry2 = myHmap.Put(2, "second"); // 2 is the key "second" is the value
GePrint(myHmap.FindEntry(2)->GetValue()); //Find using the key (which is 2 in this example)
maxon::HashMap<Int, Float> myHmap;
auto entry1 = myHmap.Put(1, 5.5); // 1 is the key 5.5 is the value
auto entry2 = myHmap.Put(2, 22.4); // 2 is the key 22.4 is the value
GePrint(String::FloatToString( myHmap.FindEntry(2)->GetValue())); //Find using the key (which is 2 in this example)
//This is an example of filling a HashMap with Atom objects as the keys
//Then assigning String values to them
BaseObject *obj1 = doc->GetFirstObject();
if(!obj1) return false;
BaseObject *obj2 = obj1->GetNext();
if(!obj2) return false;
//Create a HashMap array and insert the two objects into it. And set their values as text
//The key values lets us look up the items in the HashMap array
maxon::HashMap<C4DAtom*, String> myHmap;
maxon::Bool created = false;
auto entry1 = myHmap.FindOrCreateEntry(obj1, created);
auto entry2 = myHmap.FindOrCreateEntry(obj2, created);
//Iterate through the HM array using an iterator
//The iterator 'it' is the value of each array element
for(auto it = myHmap.Begin(); it != myHmap.End(); ++it)
auto value = it;
Int32 t = it->GetKey()->GetType(); //Get the type of object in the HM array
String keyVal = it->GetValue(); //Get the key value in the HM for this object
//We can change the keys in the HashMap if we want
if (keyVal == "first") entry1->SetValue("newKeyValue");
GePrint(String::IntToString(t) + " " + keyVal);
//Print the new key value in the HashMap
On 11/01/2015 at 16:16, xxxxxxxx wrote:
As always thanks Scott. I saw that the standard library had maps, but I didn't know the SDK had one too. That's solid, I'll try it out.
On 11/01/2015 at 19:36, xxxxxxxx wrote:
I appear to have ran into another problem. Apparently the maxon string class isn't supported as a key?
Error 1 error C2039: 'GetHashCode' : is not a member of 'String'
On 12/01/2015 at 14:02, xxxxxxxx wrote:
Just documenting my progress for anyone else who stumbles on this. I did a workaround by using char* as the key, but FindEntry isn't matching up the char strings, still looking into that.
On 13/01/2015 at 13:27, xxxxxxxx wrote:
Here's some info that I think can help you with the problems you're having with C4D's hash code:
Link in help to GetHashCode() call, takes a const Char* key and returns a static UInt:
Link to GetHashCode() call
Example code to create a C-String from C4D's String class:
// Create a char* null terminated C-string from a C4D String
size_t keyLength = keyString.GetCStringLen(STRINGENCODING_8BIT);
char* keyCharString = new char[keyLength + 1];
keyString.GetCString(keyCharString, keyLength + 1, STRINGENCODING_8BIT);
// Get the hash code using keyCharString
UInt hashCode = GetHashCode(keyCharString);
// *** Use the hashCode value here
// Delete the string when you're done, or you'll leak memory
delete  keyCharString;
keyCharString = nullptr;
I hope that helps!
SDK Support Engineer
On 13/01/2015 at 17:10, xxxxxxxx wrote:
@j_gaspe Thanks for that. That's kinda what I ended up coming up with. In my put functions for the HashMap I used GetHashCode to hash the strings. Then I basically had to take to take the GetName function of a BaseObject and run GetHashCode on that and then compare it to my keys using HashMap's FindEntry function. Roundabout but it got the job done.
On 14/01/2015 at 06:38, xxxxxxxx wrote:
Thanks for letting me know it worked out. I'll close the topic as being solved.