Creating a Path element without adding it to the Drawing List

Wow, its been a while since I’ve written a post here.  The holidays are always a busy family blur.  Well, here is the latest installment …

The path/poly element is the most used element in CC3.  You really cannot get much done with it.  Try building anything in CC3 without it (Sure you can just use more primitive elements and use multipoly & group for joining and filling, but really you are just re-creating the path/poly element).  So if you want to get something done in an XP, odds are you are going to be working with paths/polys.

If you have been following this blog or the cc2-dev-list on groups.yahoo.com, you have seen code that creates path.  The code always creates a empty drawing list element then works on this record entity to “change” it into a path/poly.  I’ve always had a bit of a bad feeling about that.  It seems that it would be more “correct” to only add completed elements to the drawing list.  So, after quite a bit of frustration, I’ve successfully  worked out the code to create a path/poly element independent of the drawing list.

The code below creates a closed path (poly) with with four points:

Code Snippet – Build a PATH2 Element

1. PATH2 *pathPtr = (PATH2*)malloc(sizeof(PATH2));
2.  
3. pathPtr->CStuff.ERLen = sizeof(PATH2);    // entity record length
4. pathPtr->CStuff.EType = ET_PATH2;         // entity type code
5. pathPtr->CStuff.EFlags = 0;               // erase/select bits
6. pathPtr->CStuff.EFlags2 = 0;              // extra flags
7. pathPtr->CStuff.EColor = 1;               // entity color
8. pathPtr->CStuff.EColor2 = 1;              // fill (2nd) color
9. pathPtr->CStuff.EThick = 0;               // pen thickness 0..25.4 mm
10. pathPtr->CStuff.WPlane = 0;               // workplane (0 = XY plane)
11. pathPtr->CStuff.ELayer = 1;               // layer
12. pathPtr->CStuff.ELStyle = 0;              // line style (0=solid)
13. pathPtr->CStuff.GroupID = 0;              // group id (0 = not grouped)
14. pathPtr->CStuff.EFStyle = 0;              // fill style (0=hollow)
15. pathPtr->CStuff.LWidth = 0.0;             // line width
16. pathPtr->CStuff.Tag = 0;                  // entity tag id
17. pathPtr->Path.SmType = 0;                 //SmType
18. pathPtr->Path.SRes = 8;                   //SRes
19. pathPtr->Path.SParm = 0.0;                //SParm
20. pathPtr->Path.EParm = 0.0;                //EParm
21. pathPtr->Path.Count = 0;                  //Count
22. pathPtr->Path.Flags = 0;                  //Flags
23. pathPtr->Path.unused = 0;                 //unused
24.  
25. GetCStuff((pENTREC)pathPtr);
26.  
27. pathPtr = (PATH2*)realloc(pathPtr, sizeof(PATH2) + sizeof(GPOINT2) * 4);
28.  
29. pathPtr->CStuff.ERLen = sizeof(PATH2) + sizeof(GPOINT2) * 4;
30.  
31. pathPtr->Path.Nodes[0].x = 0.0;            //Nodes[0]
32. pathPtr->Path.Nodes[0].y = 0.0;            //Nodes[0]
33. pathPtr->Path.Nodes[1].x = 0.0;            //Nodes[1]
34. pathPtr->Path.Nodes[1].y = 1000.0;         //Nodes[1]
35. pathPtr->Path.Nodes[2].x = 1000.0;         //Nodes[2]
36. pathPtr->Path.Nodes[2].y = 1000.0;         //Nodes[2]
37. pathPtr->Path.Nodes[3].x = 1000.0;         //Nodes[3]
38. pathPtr->Path.Nodes[3].y = 0.0;            //Nodes[3]
39.  
40. pathPtr->Path.Count = 4;
41. pathPtr->Path.EParm = 4.0;
42. pathPtr->Path.Flags = NL_CLS;
43.  
44. pENTREC pEntRec = DLApnd(NULL, (pENTREC)pathPtr);
45.  
46. EDraw(pEntRec);
47.  
48. free(pathPtr);

Quick development tip

For those of us that are not super c/c++ gurus, like me, debugging an XP add-on can be quite challenging. Over the years I've tried numerous different ways to see into the inner workings of the code.

• I first tried placing lots of InfoBox() calls to report on the code state.  This worked to a point, but when I needed to see what way going on in a dynamic cursor, or anywhere that the user needed to interact with CC3, the InfoBox() tended to interfere.  Plus building a string, that usually included numbers, just to output it to a message box seemed like a lot of work.
• Then I added a bunch of code to write to a text file.  This worked great but is was quite a bit of code and if I forgot to remove it, the end users got debug files that the shouldn't have.  Plus you still needed to do all that code for creating your output string.  And, if you wanted the file readable, you needed to include newlines, tabs etc.

Well, when we are first all taught c/c++ it is via the command line.  The command printf/cout is king.  We learn to output data to the console window in very simple ways.  As we start to develop more and more complex applications, we could, for development purposes, interject tons of these little commands to see exactly what was happening.

Unfortunately, with the development of windowing software we no longer have the console window.  Or do we?

If you are developing an XP add-on, (or any windows application for that matter) adding a console window is quite easy.  Simply slip into your code two commands: AllocConsole & FreeConsole.

Simply change your code to match the code bellow and start some searious debugging!

Code Snippet - Display Console Window

1. BOOL WINAPI DllMain (HINSTANCE hDLL, DWORD dwReason, LPVOID lpReserved)
2. {
3.     switch (dwReason)
4.     {
5.         case DLL_PROCESS_ATTACH:
6.         {
7.             AllocConsole();
8.             MyXP.ModHdl=hDLL;
9.             XPRegCmd(&MyXP);
10.             break;
11.         }
12.         case DLL_PROCESS_DETACH:
13.         {
14.             FreeConsole();
15.             XPUnregCmd(&MyXP);
16.             break;
17.         }
18.     }
19.  
20.     return TRUE;

Code name: Map Invoker

As Simon mentioned in previous post here, I am working on an application, which I am developing under the code name "Map Invoker".  It will generate random towns, from small little hamlets to large walled cities.  I've been concentrating on the algorithm side and am truely quite a ways towards a "feature complete" logic set.

So Simon was correct in stating that "He’s gone beyond proof of concept".  Soon I will be turning from generation to the interface so that all the parameters that I've included in the algorithms are exposed to the user so that the user can create an incredable range of different towns.

Once the paramter inputs are down and tested, then we will be looking into adding all the "garnish" that makes programs like this come alive.  So if you have any ideas, practical or "pie in the sky", I'd love to here them.  Either post your idea or email me at: SAUNDERL (at) HOTMAIL (dot) COM.

The Spiral Command - In Three Parts (Part #1)

The Spiral Command - In Three Parts (Part #1)
In this post and the next two posts, I will be building a spiral command.  In this post we will be dealing with the algorithm.  When we are done with this post, we will have a command that draws a spiral that would have 20 loops if it started in the middle, but we also told the algorithm to not draw the innermost 10 loops.  We have also hard currently coded the command to draw the spiral with a distance of 10 between each loop.

I will be using the name MYSPIRALM for this temporary command.  When finished, this will be the command for the macro version.

Note:  There is a naming convention that states if you have both a dialog driven command and a comand that is all command line for macros, the macro version ends with an M.

 Hardcoded values:

• Distance Between Loops: 10
• Number of Inner Loops Not Drawn: 10
• Total Number of Loops: 20
• Clockwise/Counter Clockwise: Clockwise
• Growth Between Loops: None

Our next post will implement RecData's to get the values that we currently are hardcoded.  Then, we will finish up with a dialog driven command.

Friday, August 20, 2010MyLine Command (A Complete Example)
We have finally reached the point where we can produce an entire example. In my previous post I explained how, conceptually, this command will work. Now, here is the actual code for the command along with a lot of comments.

I have also copied and commented out the definitions for the relevant elements that we are going to create.

I hope that you fire up Visual Studio and try building this code; if you are impatient though and want to just run it, here

Code Snippet - MySpiralM Command

1. ////////////////////////////////////////////////////////////////////////////
2. //
3. //    File Name: MySpiral.cpp
4. //    Written by: L. Lee Saunders
5. //    (C)2010 Beer & Pretzel Games
6. //    All rights reserved
7. //
8. ////////////////////////////////////////////////////////////////////////////
9.  
10. #include <windows.h>
11. #include <math.h>
12.  
13. extern "C"
14. {
15.     #include <xp.h>
16.     #include <Extend/Mysvc.h>
17. }
18.  
19. extern XP MyXP;
20.  
21. ////////////////////////////////////////////////////////////////////////////
22.   
23. void XPCALL DrawSpiral (int Result,int Result2,int Result3);
24. GPOINT2 CenterPoint;
25.  
26. FORMST(lpszCenterPoint,"Center Point:\0")
27.   
28. RDATA PCenterReq =
29.    { sizeof(RDATA), RD_2DC, NULL, RDF_C, (DWORD*)&CenterPoint,
30.   (DWORD*)&lpszCenterPoint, RDC_XH, DrawSpiral, NULL, NULL, 0, NULL, 0};
31. ////////////////////////////////////////////////////////////////////////////
32.   
33.   
34. ////////////////////////////////////////////////////////////////////////////
35. void XPCALL MySpiralM (void)
36. {
37.     ReqData(&PCenterReq);  //get center point
38. }
39. ////////////////////////////////////////////////////////////////////////////
40.  
41.  
42. ////////////////////////////////////////////////////////////////////////////
43. void XPCALL DrawSpiral (int Result,int Result2,int Result3)
44. {
45.     if (Result != X_OK) { CmdEnd(); return; }
46.  
47.     float Growth = 1;
48.     float LoopDistance = 10;
49.  
50.     int Rotations = 20;
51.     int InnerLoopsToSkip = 10;
52.     const char * Direction = "0\0";
53.  
54.     pENTREC pEntRec;  //Create a new drawing database entity
55.     
56.     float CenterX = CenterPoint.x;
57.     float CenterY = CenterPoint.y;
58.  
59.     int iDirection;
60.  
61.     MarkUndo();
62.  
63.     // Insert an empty path into the drawing list
64.     pEntRec=DLApndE(NULL, ET_PATH2, sizeof(PATH2)+sizeof(GPOINT2));
65.  
66.     // Get the common stuff
67.     GetCStuff(pEntRec);
68.  
69.     // Set the smoothing to Parabolic Blend (through-point)
70.     pEntRec->Path.Path.SmType = SM_PB;
71.  
72.     // Set the centerpoint of the spiral
73.     pEntRec->Path.Path.Nodes[0].x = CenterPoint.x;    
74.     pEntRec->Path.Path.Nodes[0].y = CenterPoint.y;
75.  
76.     // How many points to draw per circle
77.     const double STEPS_PER_ROTATION = 50;
78.     
79.     // Amount to add to angle at each step
80.     double increment = M_PI/STEPS_PER_ROTATION;  // Splitting up
81.  
82.     double theta = 2*M_PI*InnerLoopsToSkip;  // This allows for an open area
83.     // inside the spiral
84.  
85.     // Determines if the loops rotates clockwise or counter clockwise
86.     iDirection = strcmp(Direction, "0") == 0 ? 1 : -1;
87.  
88.     while(theta < (Rotations * 2) * M_PI)
89.     {
90.         pEntRec=DLResize(pEntRec, pEntRec->Path.CStuff.ERLen +
91.           sizeof(GPOINT2));
92.  
93.         pEntRec->Path.Path.Nodes[pEntRec->Path.Path.Count].x=(float)
94.           (CenterX + theta * cos(theta) * (1/(M_PI * 2)) * LoopDistance *
95.           iDirection);
96.         pEntRec->Path.Path.Nodes[pEntRec->Path.Path.Count].y=(float)
97.           (CenterY + theta * sin(theta) * (1/(M_PI * 2)) * LoopDistance);
98.         
99.         pEntRec->Path.Path.EParm=(float)pEntRec->Path.Path.Count;
100.         pEntRec->Path.Path.Count++;
101.         
102.         LoopDistance = LoopDistance * Growth;
103.         theta = theta + increment; //If theta grows faster then increment,
104.         //it will have wider spaces between each loop    
105.     }
106.                 
107.     EDraw(pEntRec);  //Draw our line
108.     ShowChanges();   //Needed for CC3 to "Show Changes" to the DB
109.  
110.     CmdEnd();
111.     return;
112. }
113. ////////////////////////////////////////////////////////////////////////////

How to walk the "Drawing List"

In trying to decide what element of CC3 XP programming I was going to blog about next, I started to re-read all of the old posts on the cc2-dev-l email list @ groups.yahoo.com. 

Wow, I had forgotten how much valuable information was out there. If you have the time (And it will take a bit of time) just start at the beginning and read through the threads.  I promise that you will learn something – I did!

I found a request by Linda Kekumu.  It seemed that she had a large number of maps that had lots of Notes attached to them and they were wrong.  She needed a quick way to clear out all the notes on a map, instead of manually removing them one at a time.  Peter responded with this dash of code.

The reason I selected it for this post is that it is probably the smallest piece of code that displays how to use DLScan.  Now DLScan does exactly as the name says, it scans the “Drawing List” (i.e. the drawing database) and calls a function for every “identified” element.  I say “identified” because there are times when you only want to look at a subset of the entire Drawing List.

In this new XP command, we scan the Drawing List with the DLS_Std flag, telling DLScan that we want to scan the Drawing List for “all standard all non-erased elements”.

Then in our called function (ClearNotesScan) we check the EType of each identified  element (pEntRec) .  If the EType equals ET_Note, we know it is a Note and we call DLErase to remove the element from the Drawing List.

So, with this, you can now scan through a map and look at every identified element!

Code Snippet – MyClearNotes Command

1. /////////////////////////////////////////////////////////////////////////////
2. //
3. // Program: CC3DeveloperBlog.dll
4. // File Name: MyClearNotes.cpp
5. // Written by Peter Olsson (Copied here by L. Lee Saunders)
6. // (C)2010 Beer &amp; Pretzel Games
7. // All rights reserved
8. //
9. /////////////////////////////////////////////////////////////////////////////
10. 
    
11. #include <windows.h>
12. #include <math.h>
13. 
    
14. extern"C"
15. {
16.     #include <xp.h>
17.     #include <math.h>
18. }
19. extern XP MyXP;
20. /////////////////////////////////////////////////////////////////////////////
21. 
    
22. 
    
23. /////////////////////////////////////////////////////////////////////////////
24. DWORD XPCALL ClearNotesScan(hDLIST hDList, pENTREC pEntRec, PARM p1, PARM p2)
25. {
26.     //If the Entity Record is of type "Note" then erase the Entity from DL
27.     if(pEntRec->CStuff.EType==ET_NOTE) { DLErase(pEntRec); }
28.     return 0;
29. }
30. /////////////////////////////////////////////////////////////////////////////
31. 
    
32. 
    
33. /////////////////////////////////////////////////////////////////////////////
34. void XPCALL MyClearNotes(void)
35. {
36.     //Description copied from FCW32.TXT
37.     //---------------------------------------------------------------
38.     // ClearSel - Clear All Selection bits
39.     //---------------------------------------------------------------
40.     ClearSel();
41. 
    
42.     //This sets an undo point so that every action after this to the end of
43.     //the command will be reversed if the user selects UNDO.
44.     MarkUndo();
45. 
    
46.     //Drawing list scan. We are interested in only the first three parameters
47.     // Param #1: Drawing list - If null, it is the main list
48.     // Param #2: Our Callback function for every identified element in the DL
49.     // Param #3: DSFlags. How we identify what DL elements we want
50.     DLScan(NULL, ClearNotesScan, DLS_Std, 0, 0);
51. 
    
52.     //End the command
53.     CmdEnd();
54. }
55. /////////////////////////////////////////////////////////////////////////////

MyLine Command (A Complete Example)

We have finally reached the point where we can produce an entire example.   In my previous post I explained how, conceptually, this command will work.  Now, here is the actual code for the command along with a lot of comments.

I have also copied and commented out the definitions for the relevant elements that we are going to create.

I hope that you fire up Visual Studio and try building this code; if you are impatient though and want to just run it, here is the dll.

Code Snippet - MyLine Command (A Complete Example)

1. ////////////////////////////////////////////////////////////////////////////
2. //
3. //    Written by: L. Lee Saunders
4. //    Date: 8/15/2010
5. //    (C)2010 BeerAndPretzelGames.com
6. //    All rights reserved
7. //
8. ////////////////////////////////////////////////////////////////////////////
9. #include <windows.h>
10.  
11. extern "C"
12. {  
13.     #include <XP.H>
14.     #include <Extend/Mysvc.h>
15. }
16.  
17. #define XPID 0xF000
18.  
19. void XPCALL About(void);
20. void XPCALL MYLINE(void);
21.  
22. char CList[]="MYLINE\0";
23. PCMDPROC PList[]={About,MYLINE};
24.  
25. XP MyXP =
26.    { 0, CList, PList, 0, 0, 0, XPID, 0, 500, 0, 0, 500 };
27. ////////////////////////////////////////////////////////////////////////////
28.  
29.  
30. ////////////////////////////////////////////////////////////////////////////
31. FORMST(MyAPkt,"BLOG DLL commands:\n\n"
32.        "\tMYLINE - Duplicating the Line Command #s\n\0")
33.  
34. void XPCALL About (void)
35. {
36.     FormSt(&MyAPkt,RSC(FD_MsgBox));
37. }
38. ////////////////////////////////////////////////////////////////////////////
39.  
40.  
41. ////////////////////////////////////////////////////////////////////////////
42. void XPCALL MYLINE2 (int Result,int Result2,int Result3);
43. void XPCALL MYLINE3 (int Result,int Result2,int Result3);
44.  
45. //This is the definition of LINE2
46. //==========================================================================
47. //typedef struct
48. //{
49. //    CSTUFF    CStuff;              // entity properties
50. //    GLINE2    Line;                // line properties
51. //} LINE2;
52.  
53. //This is the definition of GLINE2
54. //==========================================================================
55. //typedef struct
56. //{
57. //    GPOINT2 p1;                    // starting point
58. //    GPOINT2 p2;                    // ending point
59. //} GLINE2;
60.  
61. //This is the definition of GPOINT2
62. //==========================================================================
63. //typedef struct
64. //{
65. //    float x;
66. //    float y;
67. //} GPOINT2;
68.  
69. //This is the definition of CSTUFF
70. //==========================================================================
71. //typedef struct
72. //{
73. //    int    ERLen;                    // entity record length
74. //    unsigned char    EType;          // entity type code
75. //    char    EFlags;                  // erase/select bits
76. //    char    EFlags2;                 // extra flags
77. //    unsigned char    EColor;         // entity color
78. //    unsigned char    EColor2;        // fill (2nd) color
79. //    char    EThick;                  // pen thickness 0..25.4 mm
80. //    short    WPlane;                 // workplane (0 = XY plane)
81. //    short    ELayer;                 // layer
82. //    short    ELStyle;                // line style (0=solid)
83. //    short    GroupID;                // group id (0 = not grouped)
84. //    short    EFStyle;                // fill style (0=hollow)
85. //    float    LWidth;                 // line width
86. //    int    Tag;                      // entity tag id
87. //} CSTUFF;
88.  
89. //This is the working structure that we will use to create all the lines
90. LINE2 BuildL = {
91.     sizeof(LINE2),                // entity record length
92.     ET_LINE2,                     // entity type code
93.     0,                            // erase/select bits
94.     0,                            // extra flags
95.     1,                            // entity color
96.     1,                            // fill (2nd) color
97.     0,                            // pen thickness 0..25.4 mm
98.     0,                            // workplane (0 = XY plane)
99.     1,                            // layer
100.     0,                            // line style (0=solid)
101.     0,                            // group id (0 = not grouped)
102.     0,                            // fill style (0=hollow)
103.     0.0,                          // line width
104.     0,                            // entity tag id
105.     0.0,                          // starting point: x
106.     0.0,                          // starting point: y
107.     1.0,                          // ending point: x
108.     1.0                           // ending point: y
109. };
110.  
111. FORMST(lpszFirstPoint,"1st point:\0")
112.  
113. FORMST(lpszNextPoint,"Next point:\0")
114.  
115. RDATA P1Req =
116.    { sizeof(RDATA), RD_2DC, NULL, RDF_C, (DWORD*)&BuildL.Line.p1,
117.     (DWORD*)&lpszFirstPoint, RDC_XH, MYLINE2, NULL, NULL, 0, NULL, 0};
118.  
119. RDATA P2Req =
120.    { sizeof(RDATA), RD_2DC, NULL, RDF_C, (DWORD*)&BuildL.Line.p2,
121.     (DWORD*)&lpszNextPoint, RDC_RBAND, MYLINE3, NULL, NULL, 0, NULL, 0};
122.  
123. ////////////////////////////////////////////////////////////////////////////
124.  
125.  
126. ////////////////////////////////////////////////////////////////////////////
127. void XPCALL MYLINE (void)
128. {
129.     ReqData(&P1Req);  //get first point
130. }
131. ////////////////////////////////////////////////////////////////////////////
132.  
133.  
134. ////////////////////////////////////////////////////////////////////////////
135. void XPCALL MYLINE2 (int Result,int Result2,int Result3)
136. {
137.     if (Result != X_OK) { CmdEnd(); return; } //If we did not get valid info
138.     
139.     MarkUndoAdd();  //Enable Undo
140.     NewCsrOrg(BuildL.Line.p1.x, BuildL.Line.p1.y);  //Set cursor origin
141.     ReqData(&P2Req);  //Get next point
142. }
143. ////////////////////////////////////////////////////////////////////////////
144.  
145.  
146. ////////////////////////////////////////////////////////////////////////////
147. void XPCALL MYLINE3 (int Result,int Result2,int Result3)
148. {
149.     pENTREC pEntRec;  //Create a new drawing database entity
150.  
151.     if (Result != X_OK) { CmdEnd(); return; } //If we did not get valid info
152.  
153.     //This gets all the current stuff like current color and assigns it
154.     //to our line entity.
155.     GetCStuff(&BuildL.CStuff);
156.  
157.     //Append a copy of our line to the DB and return a pointer to the new
158.     //entity in the database.  We assign it to pEntRec.
159.     pEntRec=DLApnd(NULL,(pENTREC)&BuildL);
160.     
161.     EDraw(pEntRec);  //Draw our line
162.     ShowChanges(); //Needed for CC3 to "Show Changes" to the DB
163.  
164.     BuildL.Line.p1.x=BuildL.Line.p2.x;  //move 2nd x to 1st x
165.     BuildL.Line.p1.y=BuildL.Line.p2.y;  //move 2nd y to 1st y
166.     
167.     NewCsrOrg(BuildL.Line.p1.x,BuildL.Line.p1.y);  //Set cursor origin
168.  
169.     ReqData(&P2Req);  //Get next point
170. }
171. ////////////////////////////////////////////////////////////////////////////
172.  
173.  
174. ////////////////// DllMain - XP initialization & Unload code ///////////
175. BOOL WINAPI DllMain (HINSTANCE hDLL, DWORD dwReason, LPVOID lpReserved)
176. {
177.     switch (dwReason)
178.     {
179.         case DLL_PROCESS_ATTACH:
180.         {
181.             MyXP.ModHdl=hDLL;
182.             XPRegCmd(&MyXP);
183.             break;
184.         }
185.         case DLL_PROCESS_DETACH:
186.         {
187.             XPUnregCmd(&MyXP);
188.             break;
189.         }
190.     }
191.     return TRUE;
192. }
193. ////////////////////////////////////////////////////////////////////////////

Beads – How to Wait for Input

[Note: This is copied from the "FastCAD XP Programming Reference" that comes with the XP toolkit.  I copied this, with editing only for clarity, because it was so descriptive]

Nowhere in the Windows programming environment will you find a greater need to change your thinking than with regard to getting input.

In Windows, our programs receive messages that inform us of discrete user input - a mouse movement, button click, or a keyboard press. Other than dialog boxes, there is no way provided to wait for a complete word or line of text or other aggregate input in your program and then continue. We must write our program so that each keystroke is processed and then control is returned all the way to Windows.

This means that in a piece of code (creating a text entity, for example) we can not have one procedure that calls another to get a line of text and then continues with the next instruction when it is available, as would be done in a DOS or Unix program. The current position within that first command procedure is normally maintained on the stack, perhaps as a nested chain of procedure calls.

In Windows, after every event (such as a single key press), we have to return all the way up the stack back to Windows! This is why most Windows programs do all of their input through dialog boxes.

The FastCAD solution to this problem is to think of a command as a string of "beads" - little pieces of a command that each do one small part of the overall command, each a piece that can be done in response to an appropriate input event.

Lets take as an example a command to create a line entity. In traditional programming, its logic might be:

LineCommand:

prompt the user for the first point
- Get the first point if there was a problem getting it, end the command

prompt the user for the second point
- Get the second point if there was a problem getting it, end the command

Create the line entity

Append it to the drawing database

Draw the line entity

End the command

In FastCAD, we have an API service, ReqData, that handles data requests. We call ReqData with a packet that tells it about the data request, and then we go back to Windows.

When the data becomes available, ReqData will call another procedure specified in our original request packet to continue with our command. This means that we write our command as a series of procedures, linked together by RDATA packets, each one executing when its data becomes available, and returning to Windows when it needs to wait for more input.

The sequence looks like this:
==========================
Event: Action (Bead procedure):
- LINE function entered
- - Request first point by calling ReqData
- Line function ends

User enters the first request for a point:

Event: Action (Bead procedure):
- Second LINE function entered
- - Did the user cancel the request?
- - - End Command
- - Request second point by calling ReqData
- Second Line function ends

User enters the second request for a point:

Event: Action (Bead procedure):
- Third LINE function entered
- - Did the user cancel the request?
- - - End Command
- - Else
- - - Create the line entity
- - - Append it to the drawing database
- - - Draw the line entity
- - - End Command
-  Third Line function ends

The LINE command is implemented in 3 beads, each of which is called in response to a single event, such as a mouse click or a RETURN keypress. The ReqData service provides all of the intermediate beads that track mouse movement and build up strings of characters into words like "LINE" for you.

Next post, we will start to implement the LINE command.

Ok, you requested data, now what did you get?

Ok, so you have messed around with the RDATA function and you want to select an element, like a circle.  So you create a new RDATA function with the fallowing parameters:

• Cursor:  RDC_PICK
• Flags:  RDF_C
• Type:  RD_Pick1

 Now create a data store variable of type pEntRec.

A pEntRec type is a very important type in writing XP's.  The pEntRec type is the generic entity pointer that can point to any type of drawing entity.  So, if you selected a circle with your RDATA call, pEntRec will point to the the circle entry within the "Drawing Database"

The "Drawing Database" is the collection of all the visible elements in the map.  When we select elements, Campaign Cartographer returns a pointer to the selected element in the "Drawing Database".

Once you get a pointer to an entity, you can edit, interrogate or delete it.

Every entity shares some common data - appropriately named: CSTUFF

CStuff is defined as:

Code Snippet - CSTUFF

1. typedef struct
2. {
3.     int              ERLen;        // entity record length
4.     unsigned char    EType;        // entity type code
5.     char             EFlags;       // erase/select bits
6.     char             EFlags2;      // extra flags
7.     char             EColor;       // entity color
8.     char             EColor2;      // fill (2nd) color
9.     char             EThick;       // pen thickness 0..25.4 mm
10.     short            WPlane;       // workplane (0 = XY plane)
11.     short            ELayer;       // layer
12.     short            ELStyle;      // line style (0=solid)
13.     short            GroupID;      // group id (0 = not grouped)
14.     short            EFStyle;      // fill style (0=hollow)
15.     float            LWidth;       // line width
16.     int              Tag;          // entity tag id
17. } CSTUFF;

For example you have a pEntRec named pENTREC and you want to get the entities color:

pENTREC->CStuff.EColor

Requesting data from CC3 - RDATA

Last post I introduced the two most important functions exposed by CC3: RDATA & FORMST.

In this post I'll discuss the internals of RDATA.

Here are the important elements you need to configure for every time you declare an RDATA.

• Name - This is simply the name the holds all the separate RDATA elements together
• Type - This is where you declare what kind of data you are requesting
• Flags - These flags are the switches that tweak the RDATA call to do exactly what you want
• Data Store - Where to "put" what you have requested after it has been selected
• Prompt - This is the text that will be displayed to the user
• FormSt declaration - This is where you decide if you want to include the prompt declaration. If you already have exactly the prompt you want already declared, you can reuse it instead of creating a new one
• Cursor - Obviously selecting a single item you want a different cursor than if you want them to type in some text
• Return Procedure

When I first started to write XP's, Super Guru Peter Olsen sent me a little tool that he wrote to automatically generate the RDATA call. When I was preparing for this post, I asked Peter if he still had the app. Well, he did, but he suggested that I create an online version of the tool. So, here is a Silverlight 4 application that generates an RDATA structure for you.



In my next post, I'll use the tool to generate our RDATA and select our first element. Plus, we will start to discuss what it is exactly, that we get back from our ReqData call.

Part 2 of a Campaign Cartographer 3 XP - Or, the best part for last.

In a previous post, I discussed how an XP is in three distinct parts. This post is about the second part: Where the rubber meets the road.

Because this is the main part of the XP, describing this section in any detail would be like trying to describing how any a website works by describing how HTML works.

But, there are two main functions of every XP. Input and Communicating with the user.

Input: Feeding data from you map into your XP is a major function. If you cannot select elements or locations (points), you cannot have much of an impact on your drawing.

Communication: Having the ability to select something without telling the user what your command is expecting the user to do.

These two functions are accomplished using RDATA (Request Data) and FORMST (Format String). Using these two together, we can prompt the user, with FORMST, that we currently want a type of data (a string, a point, an element etc.) and with RDATA, we are informing CC3 that it needs to let the user collect the data we want.

Here is a simple example that implements an XP command to enter a text word:

Code Snippet: XP dll Part #2

1. void XPCALL GotText(int Result, int Result1, int Result2);
2.  
3. FORMST(lpszGetText, "Enter Text:")
4.  
5. RDATA rGetText = {sizeof(RDATA), RD_TxWord, NULL, RDF_C, (DWORD *)Text,
6. (DWORD *)&lpszGetText, RDC_NONE, GotText, NULL, NULL, 0, NULL, 0};
7.  
8. void XPCALL GetText(void)
9. {
10.     ReqData(&rGetText);
11. }
12.  
13. void XPCALL GotText(int Result, int Result1, int Result2)
14. {
15.     if(Result==X_OK)
16.     {
17.     }
18.     else
19.     {
20.         CmdEnd();
21.     }
22. }

Line 1: This is the prototype for the method that RDATA will call when it has gotten a hold of the data you requested.

Line 3: This is the FORMST declaration. This declaration creates a variable (lpszGetText) and assigns it the text "Enter Text:".  True, we could have created a string with this text, but RDATA is expecting a FORMST variable.  Plus, when we get further into the power of FORMST, you will see that is it not merely a replacement for a char array.

Lines 5 & 6:  This is the RDATA declaration.  When you learn to read it, you will see that it says it is going to go get a "Word" (a string of characters without whitespace), store it in the char array Text (not declared in the code snippet), diplaying no visible cursor, displaying the text in the FORMST as our prompt and calling our method, GotText, when the user is done entering the request.

Line 8 - 11: This is our commands original method.  It would have been declared and prototyped in Part 1 of the XP code.

Line 10:  This is the call that invokes our RDATA.

Line 13 - 22: This is our method that RDATA will call when it has gotten a hold of the data you requested.

Line 15:  This line shows that the Result parameter contains the "Status" of the request we made.  If it is "OK" then we can further process what we got.

Line 20:  CmdEnd() is the XP command that notifies CC3 that our XP function has come to an end.

Part 3 of a Campaign Cartographer 3 XP

In a previous post, I discussed how an XP is in three distinct parts. This post is about the third part: XP DllMain Boilerplate.

Here is the third part (right below your usings) of an Example XP dll. Remember that this is the very last part of a XP dll:

Code Snippet: XP dll Part #3

1. #pragma unmanaged
2. BOOL WINAPI DllMain (HINSTANCE hDLL, DWORD dwReason, LPVOID lpReserved)
3. {
4.     switch (dwReason)
5.     {
6.         case DLL_PROCESS_ATTACH:
7.         {
8.             MyXP.ModHdl=hDLL;
9.             XPRegCmd(&MyXP);
10.             break;
11.         }
12.         case DLL_PROCESS_DETACH:
13.         {
14.             XPUnregCmd(&MyXP);
15.             break;
16.         }
17.     }
18.     return TRUE;
19. }

In truth, there is only one part that is optional. That is Line 1.

Line 1: This line is only needed if you are mixing standard C/C++ with .net code.

Otherwise, just copy it all at the bottom of the file and it will just work.

Part 1 of a Campaign Cartographer 3 XP

In the last post, I discussed how an XP is in three distinct parts. This post is about the first part: XP Command declarations.

Here is the first part (right below your usings) of an Example XP dll:

Code Snippet: XP dll Part #1

1. #define XPID 0xF000
2.  
3. void XPCALL About(void);
4. void XPCALL Example1(void);
5. void XPCALL Example2(void);
6.  
7. char CList[]="EX1\0EX2\0\0";
8. PCMDPROC PList[]={About, Example1, Example2};
9.  
10. XP MyXP = { 0, CList, PList, 0, 0, 0, XPID, 0, 500, 0, 0, 500 };

Line 1: This defines the Xp ID. In the official documentation from Evolution Computing, the description is:

If your XP is going to be a commercial product, you will need to obtain an XPID number from Evolution Computing.

XPID numbers are unique XP module identifiers that allow FastCAD to identify which XPs should provide support for which custom entities and tools. That is their only purpose. Numbers in the range 0xF000-0xFFFF are available for unregistered use, but will not guarantee uniqueness against other products available to customers.

The only requirement Evolution Computing makes to issue a registered XPID number is that we know the product name, the company providing support, and that the product using it is about to be released for commercial sale. Please do not ask us for a registered XPID until your product is ready for sale.

So, unless you are about ready to sell your new add-on, just use the default.

Lines 3 through 5: These are the prototypes for the entry functions into your new commands. The first one, About, is required. It is called by the XPCFG command. If you have never tried it, run it now.

Go ahead, I'll wait.

Did you run it? If you did, you saw a list of all the loaded XP's and if you selected one of those XP's and clicked the about button, you just ran the about function for that XP. Its a good practice to keep the message box that is displayed up-to-date with a list of the commands you coded in your XP.

You may have also noticed that all the prototypes, except for the name, are exactly the same. This is because when a XP command is activated, it is up to the command to retrieve any and all data it needs, so the prototype is just defining the activation function. Think of it as your commands' Main() function.

Lines 7 & 8: These lines define CList and PList. CList is a string that defines the commands you are exposing to CC3. In the above example those commands are: "EX1" and "EX2". PList is a list of procedure names.

Notice the first one is "About". Remember, "About" is required and it must be the first procedure in the list. The next two procedures are "Example1" and "Example2". These procedures are, because of CList, mapped to the CC3 commands "EX1" and "EX2. If CList listed them in the reverse order: "EX2\0EX1\0\0", then "EX2" would be mapped to "Example1". So just remember that they are order dependant and that the first command always matches with the first procedure AFTER "About", the second command always matches with the second procedure AFTER "About" ... "

And lastly Line 10 is some required boilerplate that takes CList and PList and exposes them to CC3.

The anatomy of a basic Campaign Cartographer 3 XP

A traditional XP is written in Assembly. This is because CC3 and its predecessors were written in Assembly. But, for the last decade or more there has been a library file that allows XP development in C/C++.

An XP source code file is made up of three distinct parts.

Part 1: XP Command declarations. Here is where we place all the prototypes of the entrypoint functions of each XP command. We also add the names of each command into lists that CC3 loads. In other words, this is where CC3 looks to map a command same, like PATH, with a function to call when the user types in that command.

Part 2: This is the meat of the XP dll. This is where all the actual coding magic works.

Part 3: This is where the DllMain for the dll is declared. This boilerplate code hooks up the dll into CC3.

All the different ways to extend CC3

There are many ways to extend Campaign Cartographer 3: Macros, XP's, Intercom and reading and writing the file format directly.

In the blog posts that follow, we will be focusing on the middle two. Macros are good for a little automation but it just is not robust enough to produce complex functionality. If you can read/write the file system you could create some amazing things but A: It is a binary file B: It is compressed. So, it is just not a good place to start when learning to extend CC3.

So that leaves XP's and Intercom. They both can do great things with CC3, but from radically different directions.

An XP is an actual extension to CC3. So, if you want to add functionality to CC3, you will program an XP.

Intercom is a communication system with CC3. So, if you have an application that you want to integrate with CC3, Intercom is the system for you.

XP's will be my primary focus, simply because of the closer integration with CC3, but I will intersperse posts on Intercom to liven things up.

Welcome to CC3 Developer!

Welcome,

This is the introduction to my new blog dedicated to Campaign Cartographer (CC3) by ProFantasy Add-in development.

ProFantasy has produced a wonderful Game World Cartography product. Not just a single program, but an entire suite of add-ins that allow the user to draw just about anything map related.

The learning curve is a little steep, but just like with Photoshop, once you learn it, you have access to vasts amount of power.

Now I've written some "get started developing CC3 (and its predecessor CC2)" tutorials in the past. These are long, hand holding, filled with pictures tutorials and I plan on creating more in the future, but here I want to do the smaller howto type of posts that are the hallmark of blogging.

There is a vast API exposed for making CC3 Add-ins (also known as XP's) but, it is very lightly documented with zero examples. As I blog, I hope to expand the documentation of the API.

There are also other ways to automate and expand CC3. We will be looking at those from time to time as well.

So, sit back and enjoy the ride, as we delve into the world of CC3 programming!