Exp formula

[Locke Cole]

Parameter usage: The level parameter is zero based, so for level 1 you pass 0, for level 50 you pass 49. The chart parameter assumes a value of 100. So for a Human Warrior (100% chart) you'd pass 0. For a Nekojin Mystic (300% chart) you'd pass 200.

So I spent a lil while tonight reverse engineering the MajorMUD exp formula. Now here's the thing to realize, there's actually two formulas. There's the old classic WCC formula (which was in use when WCC sold the game to Metro), and there's the bastardized crap Metro put together to get around the 4.2 billion exp cap (better known to people with programming background as the 32-bit integer limit). I've reverse engineered the classic WCC formula, not the newer bastardized formula (which is itself broken for cases where the difference between levels exceeds 4.2 billion). Anyways. Here's the code (this is in C#)

Code Select Expand

static uint[] expModTable = {
               1,  1, 40, 20, 44, 24, 44, 24, 48, 28, 48, 28, 52,
              32, 52, 32, 56, 36, 56, 36, 60, 40, 60, 40, 65, 45,
              65, 45, 70, 50, 70, 50, 75, 55, 50, 40, 50, 40, 50,
              40, 50, 40, 50, 40, 50, 40, 50, 40, 50, 40, 23, 20,
              23, 20, 23, 20, 23, 20, 23, 20, 23, 20, 23, 20 };

static uint calcExpNeededOld(uint level, uint chart)
{
    uint res = 0,
        i = 0,
        scalemul = 0,
        scalediv = 0;

    res = ((chart * 1000) + 100000) / 100;

    while (i < level)
    {
        if (i < 26)
        {
            scalemul = expModTable[i * 2];
            scalediv = expModTable[(i * 2) + 1];
        }
        else if (i > 60)
        {
            scalemul = 105;
            scalediv = 100;
        }
        else if (i > 52)
        {
            scalemul = 110;
            scalediv = 100;
        }
        else
        {
            scalemul = 115;
            scalediv = 100;
        }

        if ((res <= (res * scalemul)) && (((res * scalemul) / scalemul) == res))
        {
            res = (res * scalemul) / scalediv;
        }
        else
        {
            res = res / 100;
            if ((res <= (res * scalemul)) && (((res * scalemul) / scalemul) == res))
                res = (res * scalemul) / scalediv;
            else
                res = (((res / 100) * scalemul) / scalediv) * 100;
            res = res * 100;
        }
        i++;
    }

    return res;
}
I've tested this and the code works fine. You can extend this code to handle 64-bit values (for higher levels) by changing the return type and the res variable to ulong. Note that when you extend it to 64-bit values you get slightly different results for levels above 37 (only a few hundred exp, if that).

For the sake of people not wanting to throw this at Visual C# and try it, here's a table showing the values for a 300% exp chart (Gaunt Ranger, Nekojin Mystic, etc).

Level	Exp needed
1	3,000
2	3,000
3	6,000
4	11,000
5	20,166
6	34,570
7	59,262
8	96,300
9	156,487
10	243,424
11	378,659
12	567,988
13	851,982
14	1,230,640
15	1,777,591
16	2,488,627
17	3,484,077
18	4,751,014
19	5,938,767
20	7,423,458
21	9,279,322
22	11,599,152
23	14,498,940
24	18,123,675
25	22,654,593
26	28,318,241
27	32,565,977
28	37,450,873
29	43,068,503
30	49,528,778
31	56,958,094
32	65,501,808
33	75,327,079
34	86,626,140
35	99,620,061
36	114,563,070
37	131,747,530
38	151,509,659
39	174,236,107
40	200,371,523
41	230,427,251
42	264,991,338
43	304,740,038
44	350,451,043
45	403,018,699
46	463,471,503
47	532,992,228
48	612,941,062
49	704,882,221
50	810,614,554
51	932,206,737
52	1,072,037,747
53	1,232,843,409
54	1,417,769,920
55	1,559,546,912
56	1,715,501,603
57	1,887,051,763
58	2,075,756,939
59	2,283,332,632
60	2,511,665,895
61	2,762,832,484
62	3,039,115,732
63	3,191,071,518
64	3,350,625,093
65	3,518,156,347
66	3,694,064,164
67	3,878,767,372
68	4,072,705,740
69	4,276,341,027
70	4,490,158,078
71	4,714,665,981
72	4,950,399,280
73	5,197,919,244
74	5,457,815,206
75	5,730,705,966
76	6,017,241,264
77	6,318,103,327
78	6,634,008,493
79	6,965,708,917
80	7,313,994,362

Comments welcome. =)

[DeathCow]

You mean I shouldn't need 1.3 zillion exp <and no i'm not joking I need 1.3 zillion exp> to level?

[Locke Cole]

Here's the same table as in my previous message, but for a 100% exp chart (Human Warrior)

Level	Exp needed
1	1,000
2	1,000
3	2,000
4	3,666
5	6,721
6	11,521
7	19,750
8	32,093
9	52,151
10	81,123
11	126,191
12	189,286
13	283,929
14	410,119
15	592,394
16	829,351
17	1,161,091
18	1,583,305
19	1,979,131
20	2,473,913
21	3,092,391
22	3,865,488
23	4,831,860
24	6,039,825
25	7,549,781
26	9,437,226
27	10,852,809
28	12,480,730
29	14,352,839
30	16,505,764
31	18,981,628
32	21,828,872
33	25,103,202
34	28,868,682
35	33,198,984
36	38,178,831
37	43,905,655
38	50,491,503
39	58,065,228
40	66,775,012
41	76,791,263
42	88,309,952
43	101,556,444
44	116,789,910
45	134,308,396
46	154,454,655
47	177,622,853
48	204,266,280
49	234,906,222
50	270,142,155
51	310,663,478
52	357,262,999
53	410,852,448
54	472,480,315
55	519,728,346
56	571,701,180
57	628,871,298
58	691,758,427
59	760,934,269
60	837,027,695
61	920,730,464
62	1,012,803,510
63	1,063,443,685
64	1,116,615,869
65	1,172,446,662
66	1,231,068,995
67	1,292,622,444
68	1,357,253,566
69	1,425,116,244
70	1,496,372,056
71	1,571,190,658
72	1,649,750,190
73	1,732,237,699
74	1,818,849,583
75	1,909,792,062
76	2,005,281,665
77	2,105,545,748
78	2,210,823,035
79	2,321,364,186
80	2,437,432,395

[Locke Cole]

By popular demand (heh), here's the code for Metro's bastardized exp formula. Note that it uses the same array as in the previous code.

Code Select Expand

static uint[] expModTable = {     
               1,  1, 40, 20, 44, 24, 44, 24, 48, 28, 48, 28, 52,
              32, 52, 32, 56, 36, 56, 36, 60, 40, 60, 40, 65, 45,
              65, 45, 70, 50, 70, 50, 75, 55, 50, 40, 50, 40, 50,
              40, 50, 40, 50, 40, 50, 40, 50, 40, 50, 40, 23, 20,
              23, 20, 23, 20, 23, 20, 23, 20, 23, 20, 23, 20 };

static ulong calcExpNeeded(uint level, uint chart)
{
    uint res = 0,       // 32-bit intermediate result
        b = 0,          // billions count
        i = 0,
        j = 0,
        scalemul = 0,
        scalediv = 0;

    res = ((chart * 1000) + 100000) / 100;

    while (i < level)
    {
        if (i < 26)
        {
            scalemul = expModTable[i * 2];
            scalediv = expModTable[(i * 2) + 1];
        }
        else if (i < 54)
        {
            scalemul = 115;
            scalediv = 100;
        }
        else if (i < 57)
        {
            scalemul = 109;
            scalediv = 100;
        }
        else if (i < 59)
        {
            scalemul = 108;
            scalediv = 100;
        }
        else if (i < 63)
        {
            scalemul = 108;
            scalediv = 100;
        }
        else if (i < 65)
        {
            scalemul = 108;
            scalediv = 100;
        }
        else if (i < 67)
        {
            scalemul = 108;
            scalediv = 100;
        }
        else if (i < 69)
        {
            scalemul = 108;
            scalediv = 100;
        }
        else if (i < 70)
        {
            scalemul = 108;
            scalediv = 100;
        }
        else
        {
            scalemul = 108;
            scalediv = 100;
        }

        j = (res * scalemul);

        if ((res <= j) && ((j / scalemul) == res))
        {
            res = (j / scalediv);
        }
        else
        {
            int x = 0;

            while ((res > j) || ((j / scalemul) != res))
            {
                x++;
                res = (res / 100);
                j = (res * scalemul);
            }

            if (x <= 1)
            {
                res = (j / scalediv);
            }
            else if (x <= 2)
            {
                res = (((res * scalemul) * 100) / scalediv);
            }
            else
            {
                res = (((res * scalemul) * 100) / scalediv);
            }
            while (x > 0)
            {
                res = (res * 100);
                x--;
            }
        }

        j = (b * scalemul) * 1000000;

        while (j >= 1000000000)
        {
            j = (j - 1000000000);
            b++;
        }

        res = (res + j);

        while (res >= 1000000000)
        {
            res = (res - 1000000000);
            b++;
        }

        i++;
    }

    return (((ulong)b * 1000000000) + res);
}

[Locke Cole]

Okay, as some of you may or may not be aware, Metro's bastardized exp formula suffers from problems at higher levels. Namely, once the difference between levels exceeds 4.2 billion, it rolls over (so you'll go back to only needing 300+ million between levels, until it creeps back up and rolls over again, etc, etc.). That bug is present in the code I pasted above (for the sake of authenticity and perfectly duplicating MMUD down to it's bugs).

The code below, implements Metro's formula with a fix for the 4.2 billion exp between level rollover issue (otherwise known as the "haven't we been here before" bug). It's a minor change on the above code, and really pretty simple, but I figured I'd provide it for completeness sake. If for some reason Metro's formula is used, I suggest using this fixed version (otherwise you'll have issues with characters above level 88).

Code Select Expand

static uint[] expModTable = {     
               1,  1, 40, 20, 44, 24, 44, 24, 48, 28, 48, 28, 52,
              32, 52, 32, 56, 36, 56, 36, 60, 40, 60, 40, 65, 45,
              65, 45, 70, 50, 70, 50, 75, 55, 50, 40, 50, 40, 50,
              40, 50, 40, 50, 40, 50, 40, 50, 40, 50, 40, 23, 20,
              23, 20, 23, 20, 23, 20, 23, 20, 23, 20, 23, 20 };

static ulong calcExpNeededFixed(uint level, uint chart)
{
    ulong k = 0;        // 64-bit intermediate result
    uint res = 0,       // 32-bit intermediate result
        b = 0,          // billions count
        i = 0,
        j = 0,
        scalemul = 0,
        scalediv = 0;

    res = ((chart * 1000) + 100000) / 100;

    while (i < level)
    {
        if (i < 26)
        {
            scalemul = expModTable[i * 2];
            scalediv = expModTable[(i * 2) + 1];
        }
        else if (i < 54)
        {
            scalemul = 115;
            scalediv = 100;
        }
        else if (i < 57)
        {
            scalemul = 109;
            scalediv = 100;
        }
        else if (i < 59)
        {
            scalemul = 108;
            scalediv = 100;
        }
        else if (i < 63)
        {
            scalemul = 108;
            scalediv = 100;
        }
        else if (i < 65)
        {
            scalemul = 108;
            scalediv = 100;
        }
        else if (i < 67)
        {
            scalemul = 108;
            scalediv = 100;
        }
        else if (i < 69)
        {
            scalemul = 108;
            scalediv = 100;
        }
        else if (i < 70)
        {
            scalemul = 108;
            scalediv = 100;
        }
        else
        {
            scalemul = 108;
            scalediv = 100;
        }

        j = (res * scalemul);

        if ((res <= j) && ((j / scalemul) == res))
        {
            res = (j / scalediv);
        }
        else
        {
            int x = 0;

            while ((res > j) || ((j / scalemul) != res))
            {
                x++;
                res = (res / 100);
                j = (res * scalemul);
            }

            if (x <= 1)
            {
                res = (j / scalediv);
            }
            else if (x <= 2)
            {
                res = (((res * scalemul) * 100) / scalediv);
            }
            else
            {
                res = (((res * scalemul) * 100) / scalediv);
            }
            while (x > 0)
            {
                res = (res * 100);
                x--;
            }
        }

        k = ((ulong)b * scalemul) * 1000000;

        while (k >= 1000000000)
        {
            k = (k - 1000000000);
            b++;
        }

        res = (res + (uint)k);

        while (res >= 1000000000)
        {
            res = (res - 1000000000);
            b++;
        }

        i++;
    }

    return (((ulong)b * 1000000000) + res);
}