Elin:Code Analysis/Fishing

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Calculations

Fish LV

The formula to calculate the fish LV that can be caught based on your fishing level:

fishLV = rnd(fishingLevel * 2) + 1
  • fishingLevel: Your current fishing skill level.
  • rnd: A random number between 0 and the value passed into the function.

Adjusted Fish LV

The adjusted fish LV is calculated during item creation. It uses multiple calls to the rnd function and adds a hardcoded value of +2 at the end. The final adjusted level becomes:

adjustedLV = fishLV + 2 + rnd(rnd(rnd(rnd(Mathf.Min(fishLV * 2, 20)) + 1) + 1) + 1)
  • The adjustment process involves:
    • Determining the base fishLV as rnd(fishingLevel * 2) + 1.
    • Applying multiple calls to the rnd function:
      • rnd generates a random number between 0 and (max - 1).
      • Each call depends on the result of the previous rnd, gradually narrowing down the possible range.
    • Adding a hardcoded +2 to ensure the adjusted LV always has an offset.
  • Note: While it’s rare, the final result of the multiple calls to rnd can theoretically be as high as 19, resulting in a significant boost to the adjusted LV.

Example

If your fishing level is 10:

  • Base LV:
    • fishLV = rnd(10 * 2) + 1 = rnd(20) + 1.
    • Example result: 10.
  • Adjustments:
    • First rnd(20) → Result = 7.
    • Second rnd(7 + 1) → Result = 3.
    • Third rnd(3 + 1) → Result = 2.
    • Fourth rnd(2 + 1) → Result = 0.
  • Final Adjusted LV:
    • adjustedLV = 10 + 2 + 0 = 12.

Fish LV Range Table

Fishing Level Minimum LV Maximum LV
1 3 4
2 3 6
3 3 8
4 3 10
5 3 12
6 3 14
7 3 16
8 3 18
9 3 20
10 3 22
11 3 24
12 3 26
13 3 28
14 3 30
15 3 32
16 3 34
17 3 36
18 3 38
19 3 40

Code (EA 23.67 fix 6)

int num3 = EClass.rnd(num * 2) + 1;
thing = ThingGen.Create("fish", -1, num3);

Number of Fish

The formula to calculate the number of fish you can catch based on your fishing level:

numberOfFish = rnd(fishingLevel / (fishLV + 10)) + 1
  • fishingLevel: Your current fishing skill level.
  • fishLV: The fish LV.
  • rnd: A random number between 0 and the value passed into the function.

Example

If your fishing level is 22, and the fish LV is determined to be 1, the potential number of fish is calculated as:

rnd(22 / (1 + 10)) + 1

This simplifies to:

rnd(22 / 11) + 1

The rnd(2) generates a random number between 0 and 1. Adding 1 ensures that you will catch at least 1 fish, and the number of fish can either be 1 or 2, depending on the random result.

Adding Land Feats

The initial chance of catching one extra fish starts at 5%.

If the land feats include:

  • Beach (3604): Adds 20% to the base chance.
  • Sea (3605): Adds 20% to the base chance.
  • Fishing Spot (3706): Adds 25% to the base chance.

Since only Sea (3605) or Beach (3604) can be present at the same time (not both), the total chance is calculated as:

chanceForOneMoreFish = 5
chanceForOneMoreFish += isBeach * 20 + isSea * 20 + isFishingSpot * 25

Where:

  • isBeach: A flag (either 0 or 1) indicating whether the land feat is a Beach (3604).
  • isSea: A flag (either 0 or 1) indicating whether the land feat is Sea (3605).
  • isFishingSpot: A flag (either 0 or 1) indicating whether the land feat is a Fishing Spot (3706).

For example:

  • If Sea (3605) is present, and Fishing Spot (3706) is also present:
chanceForOneMoreFish = 5 + 1 * 20 + 1 * 25 = 50
  • If Beach (3604) is present instead of Sea (3605):
chanceForOneMoreFish = 5 + 1 * 20 + 1 * 25 = 50

Checking the Chance to Increase the Number of Fish

The chanceForOneMoreFish value is compared to a random number generated by the rnd(100) function, which produces a number between 0 and 99 (inclusive).

If chanceForOneMoreFish is greater than or equal to the random number, the number of fish will increase by 1.

This check is implemented with:

if (chanceForOneMoreFish >= rnd(100))

For example:

  • If chanceForOneMoreFish = 50, and the random number generated by rnd(100) is 50 or less, you will catch an additional fish.

Example with Land Feats

Example 1: Fishing Spot (3706) and Sea (3605)

Let's say your fishing level is 22, and the fish LV is 1. The base number of fish is calculated as:

numberOfFish = rnd(22 / (1 + 10)) + 1 = rnd(2) + 1

This gives 1 or 2 fish, depending on the random result.

Now, evaluating the land feats:

  • Start with chanceForOneMoreFish = 5 (base chance).
  • Sea (3605) adds 20.
  • Fishing Spot (3706) adds 25.

The new chanceForOneMoreFish becomes:

chanceForOneMoreFish = 5 + 20 + 25 = 50

Next, the random chance is checked:

if (chanceForOneMoreFish >= rnd(100))

If the random number generated by rnd(100) is 50 or less, the number of fish will increase by 1. Thus:

  • numberOfFish = numberOfFish + 1 (if the random check passes).
  • If the random number exceeds 50, the number of fish remains unchanged.
Example 2: Fishing Spot (3706) and Beach (3604)

For the same fishing level and fish LV, the land feats contribute:

  • Beach (3604) adds 20.
  • Fishing Spot (3706) adds 25.

The total chanceForOneMoreFish remains:

chanceForOneMoreFish = 5 + 20 + 25 = 50

The random check behaves the same as above, with the same chance for an additional fish.

Number of Fish Table

Fish LV Minimum Fishing Level for 2 Fish Minimum Fishing Level for 3 Fish Minimum Fishing Level for 4+ Fish
1 22 33 44, etc.
5 30 45 60, etc.
10 40 60 80, etc.
15 50 75 100, etc.
20 60 90 120, etc.
25 70 105 140, etc.
30 80 120 160, etc.
35 90 135 180, etc.
40 100 150 200, etc.

Note: Values for 4+ fish follow the same progression pattern (incrementing by the same interval as earlier columns).

Code (EA 23.67 fix 6)

num2 = EClass.rnd(num / (num3 + 10)) + 1;
int num4 = 5;
if (EClass.Branch != null)
{
	num4 += EClass.Branch.Evalue(3604) * 20 + EClass.Branch.Evalue(3605) * 20 + EClass.Branch.Evalue(3706) * 25;
}
if (num4 >= EClass.rnd(100))
{
	num2++;
}
}
if (thing != null)
{
	thing.SetNum(num2);
	thing.SetBlessedState(BlessedState.Normal);
}

Fishing Speed

The fishing process involves two key variables:

  • progress: Represents the overall duration or percentage of fishing completion, ranging from 0 to 100.
  • hit: Tracks the number of attempts made during the fishing fight. The following conditions apply:
    • Increase: hit increments on each attempt until either:
      • The fish is caught (when hit > random threshold).
      • Certain random conditions reset hit to 0.

Success

The formula to calculate the success threshold for catching a fish is:

successThreshold = Mathf.Clamp(10 - rnd(fishingLevel + 1) / 10, 5, 10)
  • fishingLevel: Your current fishing skill level.
  • rnd: A random number between 0 and the value passed into the function.
  • Clamp: Ensures the value stays between 5 (easiest) and 10 (hardest).

The actual success logic occurs as follows:

if (hit > rnd(successThreshold)) {
    hit = 100;
    progress = MaxProgress;
}
  • hit: Tracks the current number of attempts. The fish is caught if hit exceeds the random roll of the successThreshold.
  • progress: Automatically completes when success occurs.

Example

If your fishing level is 20, the calculation proceeds as follows:

  1. rnd(20 + 1) generates a random number between 0 and 20.
  2. This random number is divided by 10 and subtracted from 10.
  3. The result is clamped to the range [5, 10], determining the successThreshold.

For example:

  • If rnd(21) = 10, the calculation is:
successThreshold = Mathf.Clamp(10 - (10 / 10), 5, 10) = 9

A random roll of rnd(9) determines the threshold. If hit > rnd(9), the fish is caught.

Success Threshold Table

Fishing Level Min successThreshold Max successThreshold
1 10 10
5 10 10
10 9 10
15 9 10
20 8 10
25 8 10
30 7 10
35 7 10
40 6 10
45 6 10
50 5 10
55 5 10
60 5 10

Reset

The formula to determine whether hit resets is:

resetThreshold = Mathf.Clamp(10 - rnd(fishingLevel + 1) / 5, 2, 10)
  • fishingLevel: Your current fishing skill level.
  • rnd: A random number between 0 and the value passed into the function.
  • Clamp: Ensures the value stays between 2 (easiest threshold to reset) and 10 (hardest threshold to reset).

If rnd(resetThreshold) equals 0, and progress >= 10, the hit counter resets to 0.

Example

If your fishing level is 30, the calculation proceeds as follows:

  1. rnd(30 + 1) generates a random number between 0 and 30.
  2. This random number is divided by 5 and subtracted from 10.
  3. The result is clamped to the range [2, 10], determining the resetThreshold.

For example:

  • If rnd(31) = 10, the calculation is:
resetThreshold = Mathf.Clamp(10 - (10 / 5), 2, 10) = 8

A second random roll, rnd(8), is performed. If the result is 0, the hit counter resets.

Reset Threshold Table

Fishing Level Min resetThreshold Max resetThreshold
1 10 10
5 9 10
10 8 10
15 7 10
20 6 10
25 5 10
30 4 10
35 3 10
40 2 10
45 2 10
50 2 10

Code (EA 23.67 fix 6)

public override void OnProgress()
{
	if (this.owner.IsPC && (this.owner.Tool == null || !this.owner.Tool.HasElement(245, 1)))
	{
		this.Cancel();
		return;
	}
	if (this.hit >= 0)
	{
		this.owner.renderer.PlayAnime(AnimeID.Fishing, default(Vector3), false);
		this.owner.PlaySound("fish_fight", 1f, true);
		this.Ripple();
		int a = Mathf.Clamp(10 - EClass.rnd(this.owner.Evalue(245) + 1) / 10, 5, 10);
		if (this.hit > EClass.rnd(a))
		{
			this.hit = 100;
			this.progress = this.MaxProgress;
		}
		this.hit++;
		return;
	}
	if (EClass.rnd(Mathf.Clamp(10 - EClass.rnd(this.owner.Evalue(245) + 1) / 5, 2, 10)) == 0 && this.progress >= 10)
	{
		this.hit = 0;
	}
	if (this.progress == 2 || (this.progress >= 8 && this.progress % 6 == 0 && EClass.rnd(3) == 0))
	{
		this.owner.renderer.PlayAnime(AnimeID.Shiver, default(Vector3), false);
		this.Ripple();
	}
}

Chances and Probability

Each item or fish has a unique probability of being generated, determined by the following rules and calculations:

Roll Logic
Nothing If this succeeds, no further rolls occur.
Rare Item Checked if "Nothing" fails; if this succeeds, no further rolls occur.
Junk Checked if both "Nothing" and "Rare Item" fail; if this succeeds, no further rolls occur.
Fish The fallback/default roll if all previous rolls fail.

Initial Roll: Chance to Catch Nothing

The first roll determines whether the player catches anything at all. If this roll fails, no item or fish is generated, and the function returns null. The chance to catch nothing is calculated as follows:

if (rnd(3 + fishingLevel) == 0)
{
    return null;
}
  • Formula: rnd(3 + fishingLevel) generates a random number between 0 and (3 + fishingLevel - 1), inclusive.
  • Condition: If the result is 0, the roll fails, and nothing is caught.
Probability

The probability of catching nothing decreases as the player's fishing level increases:

  • Maximum Value for the Roll: 3 + fishingLevel, where fishingLevel = c.Evalue(245).
  • Chance to Catch Nothing:
    • 1 / (3 + fishingLevel)

For example:

  • At Fishing Level 1:
    • rnd(3 + 1) generates a number between 0 and 3.
    • Probability of 0: 1 / 4 (25%).
  • At Fishing Level 10:
    • rnd(3 + 10) generates a number between 0 and 12.
    • Probability of 0: 1 / 13 (~7.69%).

This means that higher fishing levels significantly reduce the chance of failing the roll and increase the likelihood of catching something.

Conditional Rolls: Rare Items and Rewards

This section determines whether a rare item or reward is generated. The outermost condition checks if a random roll succeeds. If the condition is met, nested conditions evaluate the type of item to generate.

if (rnd(20) == 0)
  • Condition: Pass a random roll: rnd(20) == 0.

If this condition is satisfied, the following rolls determine the item generated:

Ancient Book

The Ancient Book is one of the rare items that can be generated during fishing if specific conditions are met. Its generation depends on a random roll after passing the initial check.

if (rnd(30) == 0)
{
    text = "book_ancient";
}
  • Condition: The item is generated if rnd(30) == 0.
  • Probability: 1 / 30, or approximately 3.33%.

If this condition is satisfied, the Ancient Book is created as the reward.

Platinum Coin

The Platinum Coin is another rare item that can be generated during fishing. Its generation depends on a random roll.

if (rnd(35) == 0)
{
    text = "plat";
}
  • Condition: The item is generated if rnd(35) == 0.
  • Probability: 1 / 35 (~2.86%).

If this condition is satisfied, a Platinum Coin is created as the reward.

Scratch Card

The Scratch Card is a replacement item that can be generated after the Platinum Coin roll. Its generation depends on a random roll following the successful Platinum Coin condition.

if (rnd(2) == 0)
{
    text = "scratchcard";
}
  • Condition: The item is generated if rnd(2) == 0, replacing the Platinum Coin.
  • Probability: 1 / 2 (50%), but it depends on the successful Platinum Coin roll.
  • Dependent Probability: 1 / (20 * 35 * 2) (~0.071%).
    • Calculated as:
      • Rare Item Roll: 1 / 20 (5%).
      • Platinum Coin Roll: 1 / 35 (~2.86%).
      • Scratch Card Roll: 1 / 2 (50%).

If this condition is satisfied, the Scratch Card replaces the Platinum Coin as the reward.

Casino Coin

The Casino Coin is another replacement item that can be generated after the Platinum Coin roll. Its generation depends on a random roll following the successful Platinum Coin condition.

if (rnd(3) == 0)
{
    text = "casino_coin";
}
  • Condition: The item is generated if rnd(3) == 0, replacing the Platinum Coin.
  • Probability: 1 / 3 (~33.33%), but it depends on the successful Platinum Coin roll.
  • Dependent Probability: 1 / (20 * 35 * 3) (~0.048%).
    • Calculated as:
      • Rare Item Roll: 1 / 20 (5%).
      • Platinum Coin Roll: 1 / 35 (~2.86%).
      • Casino Coin Roll: 1 / 3 (~33.33%).

If this condition is satisfied, the Casino Coin replaces the Platinum Coin as the reward.

Strange Coin

The Strange Coin is another replacement item that can be generated after the Platinum Coin roll. Its generation depends on a random roll following the successful Platinum Coin condition.

if (rnd(3) == 0)
{
    text = "gacha_coin";
}
  • Condition: The item is generated if rnd(3) == 0, replacing the Platinum Coin.
  • Probability: 1 / 3 (~33.33%), but it depends on the successful Platinum Coin roll.
  • Dependent Probability: 1 / (20 * 35 * 3) (~0.048%).
    • Calculated as:
      • Rare Item Roll: 1 / 20 (5%).
      • Platinum Coin Roll: 1 / 35 (~2.86%).
      • Strange Coin Roll: 1 / 3 (~33.33%).

If this condition is satisfied, the Strange Coin replaces the Platinum Coin as the reward.

Statues

Statues are extremely rare items that can be generated after the Platinum Coin roll. Their generation depends on a random roll, with one of seven possible statues being selected.

if (rnd(50) == 0)
{
    text = "Randomly choose one of these statues: "
           "Statue of Earth", 
           "Statue of Element", 
           "Statue of Harvest", 
           "Statue of Healing", 
           "Statue of Luck", 
           "Statue of Machine", 
           "Statue of Wind";
}
  • Condition: A statue is generated if rnd(50) == 0.
  • Probability: 1 / 50 (2%), but it depends on the successful Platinum Coin roll.
  • Dependent Probability: 1 / (20 * 35 * 50) (~0.00286%).
    • Calculated as:
      • Rare Item Roll: 1 / 20 (5%).
      • Platinum Coin Roll: 1 / 35 (~2.86%).
      • Statue Roll: 1 / 50 (2%).

If this condition is satisfied, one of the following statues is randomly selected:

  • Statue of Earth
  • Statue of Element
  • Statue of Harvest
  • Statue of Healing
  • Statue of Luck
  • Statue of Machine
  • Statue of Wind

Each statue has an equal probability of being selected from the pool of seven statues.

  • Probability of a Specific Statue: 1 / 7 (~14.29%) of the statue roll.
  • Dependent Probability for a Specific Statue: 1 / (20 * 35 * 50 * 7) (~0.00041%).
Small Medal

The Small Medal is a rare item that can be generated during fishing. Its generation depends on two random rolls: a base roll and a level-dependent threshold check.

if (rnd(40) == 0 && rnd(40) < fishingLevel / 3 + 10)
{
    text = "medal";
}
  • Condition:
    • The first roll succeeds if rnd(40) == 0 (2.5%).
    • The second roll succeeds if rnd(40) < fishingLevel / 3 + 10.
  • Probability:
    • The first roll has a fixed probability: 1 / 40 (2.5%).
    • The second roll's probability depends on the player's fishing level:
      • Higher fishing levels increase the threshold (fishingLevel / 3 + 10), making it easier to succeed.
  • Minimum Fishing Level for Consistent Success:
    • To always pass the second roll, the threshold must reach or exceed 40. Solve for:
      • fishingLevel / 3 + 10 >= 40.
      • fishingLevel >= (40 - 10) * 3.
      • fishingLevel >= 90.
    • At fishingLevel = 90, the threshold becomes 90 / 3 + 10 = 40, ensuring consistent success.
  • Dependent Probability:
    • Combined probability: (1 / 20) * (1 / 40) * (fishingLevel-dependent threshold).
    • Example for Fishing Level 10:
      • Threshold: 10 / 3 + 10 = ~13.33.
      • Second roll succeeds if rnd(40) < 13, or 13 / 40 (32.5%).
      • Combined Probability: (1 / 20) * (1 / 40) * (13 / 40) (~0.01625%).

Junk Items

Junk items are a category of low-value rewards that can be generated during fishing. Their generation depends on a random roll after all higher-priority items (e.g., rare items, medals) have failed to generate.

if (rnd(5 + fishingLevel / 3) == 0)
{
    thing = "Randomly choose one of these junk items: "
            "Boots",
            "Empty Bottle (1)",
            "Empty Bottle (2)",
            "Empty Can (1)",
            "Empty Can (2)",
            "Flotsam from the North",
            "Lucky Cat",
            "Rubber Duck",
            "Rubber Putit",
            "Rubber Snail",
            "Sandal (1)",
            "Sandal (2)",
            "Sea Pants";
}
  • Condition: Junk items are generated if:
    • The rare item roll and all higher-priority rolls fail.
    • The following roll succeeds: rnd(5 + fishingLevel / 3) == 0.
  • Probability:
    • The probability depends on the player's fishing level:
      • 1 / (5 + fishingLevel / 3).
      • Higher fishing levels reduce the chance of junk items being generated, as the denominator increases.
  • Junk Item Pool:
    • If this roll succeeds, one item is randomly selected from the following list (15 items total):
      • Boots
      • Empty Bottle (1)
      • Empty Bottle (2)
      • Empty Can (1)
      • Empty Can (2)
      • Flotsam from the North
      • Lucky Cat
      • Rubber Duck
      • Rubber Putit
      • Rubber Snail
      • Sandal (1)
      • Sandal (2)
      • Sea Pants
  • Probability of a Specific Junk Item:
    • Equal chance for each item in the list: 1 / 15 (~6.67%) of junk roll success.
Example Calculation
  • At Fishing Level 10:
    • Threshold for junk roll: 5 + 10 / 3 = ~8.33.
    • Probability of junk roll succeeding: 1 / 8 (12.5%).
    • Probability of a specific junk item: 1 / 8 * 1 / 15 = 1 / 120 (~0.83%).

Fish

The generation of fish happens as the default outcome when all higher-priority rolls fail:

  • Dependencies:
    • The fish roll occurs if:
      • The "Nothing" roll fails.
      • The "Rare Item" roll fails.
      • The "Junk" roll fails.
Probability Context

Since the fish roll occurs as the final fallback, its probability is calculated as:

  • Probability of Fish Roll:

1 - P(Nothing) - P(Rare Item) - P(Junk)

  • Dependent Probabilities:
    • This depends on:
      • Fishing level (affects the probability of "Nothing" and "Junk").
      • Success/failure of preceding rolls.
Example Calculation for Whale

At Fishing Level 19, the minimum fishing level for the Whale is 19. If the adjustedLV is 40 or higher, the Whale can be caught.

To calculate the probability of catching the Whale:

P(Whale) = 50 / Total Chance of All Eligible Fish

If the total chance for all eligible fish at Fishing Level 19 is 22050, then:

P(Whale) = 50 / 22050 = 0.00227 or ~0.227%
Fish Probability Table (Fish LV 40)
Name Chance Probability (Independent)
Tadpole 1000 1000 / 22050 (~4.54%)
Bitterling 1000 1000 / 22050 (~4.54%)
Turtle 200 200 / 22050 (~0.91%)
Goby 1000 1000 / 22050 (~4.54%)
Muddler 1000 1000 / 22050 (~4.54%)
Goldfish 200 200 / 22050 (~0.91%)
Carp 100 100 / 22050 (~0.45%)
Sweetfish 1000 1000 / 22050 (~4.54%)
Sea Urchin 200 200 / 22050 (~0.91%)
Sardine 1000 1000 / 22050 (~4.54%)
Eel 500 500 / 22050 (~2.27%)
Bass 1000 1000 / 22050 (~4.54%)
Scad 1000 1000 / 22050 (~4.54%)
Arowana 600 600 / 22050 (~2.72%)
Tilefish 1000 1000 / 22050 (~4.54%)
Tuna 400 400 / 22050 (~1.81%)
Striped Jack 1000 1000 / 22050 (~4.54%)
Mackerel 1000 1000 / 22050 (~4.54%)
Bonito 1000 1000 / 22050 (~4.54%)
Red Bream 200 200 / 22050 (~0.91%)
Black Bass 1000 1000 / 22050 (~4.54%)
Blowfish 200 200 / 22050 (~0.91%)
Sea Bream 500 500 / 22050 (~2.27%)
Flatfish 1000 1000 / 22050 (~4.54%)
Tuna (2) 500 500 / 22050 (~2.27%)
Sand Borer 1000 1000 / 22050 (~4.54%)
Salmon 500 500 / 22050 (~2.27%)
Sunfish 1000 1000 / 22050 (~4.54%)
Shark 100 100 / 22050 (~0.45%)
Deep Sea Fish 1000 1000 / 22050 (~4.54%)
Ancient Fish 200 200 / 22050 (~0.91%)
Moonfish 500 500 / 22050 (~2.27%)
Coelacanth 100 100 / 22050 (~0.45%)
Whale 50 50 / 22050 (~0.23%)

All Probability Table

Item Probability (Independent) Probability (Dependent) Notes
Nothing 1 / (3 + fishingLevel) N/A Higher fishing levels reduce the chance of this outcome.
Rare Item 1 / 20 (5%) 1 / 20 Determines if a rare item roll happens.
Ancient Book 1 / 30 (~3.33%) 1 / (20 * 30) (~0.167%) Requires a rare item roll success, then its own probability.
Platinum Coin 1 / 35 (~2.86%) 1 / (20 * 35) (~0.143%) Requires a rare item roll success, then its own probability.
Scratch Card 1 / 2 (50%) 1 / (20 * 35 * 2) (~0.071%) Replaces Platinum Coin if condition is met.
Casino Coin 1 / 3 (33.3%) 1 / (20 * 35 * 3) (~0.048%) Replaces Platinum Coin if condition is met.
Strange Coin 1 / 3 (33.3%) 1 / (20 * 35 * 3) (~0.048%) Replaces Platinum Coin if condition is met.
Statue 1 / 50 (2%) 1 / (20 * 35 * 50) (~0.00286%) Requires a rare item roll success. One of seven statues is randomly selected.
Specific Statue 1 / 7 (~14.29% of Statue Roll) 1 / (20 * 35 * 50 * 7) (~0.00041%) Probability of obtaining a specific statue.
Small Medal Level-dependent (1 / 20) * (1 / 40) * (fishingLevel threshold) Requires two successful rolls. Consistent success at fishingLevel >= 90.
Junk Level-dependent 1 / (5 + fishingLevel / 3) Requires rare item roll to fail. Probability decreases with higher fishing levels.
Specific Junk 1 / 15 (~6.67%) (1 / (5 + fishingLevel / 3)) * (1 / 15) Probability of obtaining a specific junk item.
Fish fishChance / fishTotalChance 1 - P(Nothing) - P(Rare Item) - P(Junk) Default outcome if all other rolls fail.

Code (EA 23.67 fix 6)

public static Thing Makefish(Chara c)
{
	int num = c.Evalue(245);
	if (EClass.rnd(3 + num) == 0)
	{
		return null;
	}
	int[] source = new int[]
	{
		233,
		235,
		236,
		236,
		236,
		1170,
		1143,
		1144,
		727,
		728,
		237,
		869,
		1178,
		1179,
		1180
	};
	int num2 = 1;
	string text = "";
	if (c.IsPC || EClass.rnd(20) == 0)
	{
		if (EClass.rnd(30) == 0)
		{
			text = "book_ancient";
		}
		if (EClass.rnd(35) == 0 || EClass.debug.enable)
		{
			text = "plat";
			if (EClass.rnd(2) == 0)
			{
				text = "scratchcard";
			}
			if (EClass.rnd(3) == 0)
			{
				text = "casino_coin";
			}
			if (EClass.rnd(3) == 0)
			{
				text = "gacha_coin";
			}
			if (EClass.rnd(50) == 0 || EClass.debug.enable)
			{
				text = new string[]
				{
					"659",
					"758",
					"759",
					"806",
					"828",
					"1190",
					"1191"
				}.RandomItem<string>();
			}
		}
		if (EClass.rnd(40) == 0 && EClass.rnd(40) < num / 3 + 10)
		{
			text = "medal";
		}
	}
	Thing thing;
	if (text != "")
	{
		thing = ThingGen.Create(text, -1, EClass._zone.ContentLv);
	}
	else if (EClass.rnd(5 + num / 3) == 0)
	{
		thing = ThingGen.Create(source.RandomItem<int>().ToString() ?? "", -1, -1);
	}
	else
	{
		int num3 = EClass.rnd(num * 2) + 1;
		thing = ThingGen.Create("fish", -1, num3);
		num2 = EClass.rnd(num / (num3 + 10)) + 1;
		int num4 = 5;
		if (EClass.Branch != null)
		{
			num4 += EClass.Branch.Evalue(3604) * 20 + EClass.Branch.Evalue(3605) * 20 + EClass.Branch.Evalue(3706) * 25;
		}
		if (num4 >= EClass.rnd(100))
		{
			num2++;
		}
	}
	if (thing != null)
	{
		thing.SetNum(num2);
		thing.SetBlessedState(BlessedState.Normal);
	}
	return thing;
}