Gen 1: Add support for Guaranteed Pokemon Catching

2 files changed, 46 insertions, 4 deletions

diff --git a/src/com/sneed/pkrandom/constants/Gen1Constants.java b/src/com/sneed/pkrandom/constants/Gen1Constants.java
index 3476103..204608e 100644
--- a/src/com/sneed/pkrandom/constants/Gen1Constants.java
+++ b/src/com/sneed/pkrandom/constants/Gen1Constants.java
@@ -93,6 +93,8 @@ public class Gen1Constants {
 
     public static final int towerMapsStartIndex = 0x90, towerMapsEndIndex = 0x94;
 
+    public static final String guaranteedCatchPrefix = "CF7EFE01";
+
     public static final Type[] typeTable = constructTypeTable();
 
     private static Type[] constructTypeTable() {
diff --git a/src/com/sneed/pkrandom/romhandlers/Gen1RomHandler.java b/src/com/sneed/pkrandom/romhandlers/Gen1RomHandler.java
index 470d7c7..657df3e 100755
--- a/src/com/sneed/pkrandom/romhandlers/Gen1RomHandler.java
+++ b/src/com/sneed/pkrandom/romhandlers/Gen1RomHandler.java
@@ -43,10 +43,7 @@ import java.util.TreeMap;
 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 

-import com.sneed.pkrandom.FileFunctions;

-import com.sneed.pkrandom.GFXFunctions;

-import com.sneed.pkrandom.MiscTweak;

-import com.sneed.pkrandom.Settings;

+import com.sneed.pkrandom.*;

 import com.sneed.pkrandom.constants.*;

 import com.sneed.pkrandom.exceptions.RandomizationException;

 import com.sneed.pkrandom.exceptions.RandomizerIOException;

@@ -1816,6 +1813,24 @@ public class Gen1RomHandler extends AbstractGBCRomHandler {
         return (romEntry.getValue("StaticPokemonSupport") > 0) ? "Complete" : "No Static Pokemon";

     }

 

+    private static int find(byte[] haystack, String hexString) {

+        if (hexString.length() % 2 != 0) {

+            return -3; // error

+        }

+        byte[] searchFor = new byte[hexString.length() / 2];

+        for (int i = 0; i < searchFor.length; i++) {

+            searchFor[i] = (byte) Integer.parseInt(hexString.substring(i * 2, i * 2 + 2), 16);

+        }

+        List<Integer> found = RomFunctions.search(haystack, searchFor);

+        if (found.size() == 0) {

+            return -1; // not found

+        } else if (found.size() > 1) {

+            return -2; // not unique

+        } else {

+            return found.get(0);

+        }

+    }

+

     private void populateEvolutions() {

         for (Pokemon pkmn : pokes) {

             if (pkmn != null) {

@@ -2091,6 +2106,8 @@ public class Gen1RomHandler extends AbstractGBCRomHandler {
         if (romEntry.getValue("CatchingTutorialMonOffset") != 0) {

             available |= MiscTweak.RANDOMIZE_CATCHING_TUTORIAL.getValue();

         }

+

+        available |= MiscTweak.GUARANTEED_POKEMON_CATCHING.getValue();

         return available;

     }

 

@@ -2114,6 +2131,8 @@ public class Gen1RomHandler extends AbstractGBCRomHandler {
             updateTypeEffectiveness();

         } else if (tweak == MiscTweak.RANDOMIZE_CATCHING_TUTORIAL) {

             randomizeCatchingTutorial();

+        } else if (tweak == MiscTweak.GUARANTEED_POKEMON_CATCHING) {

+            enableGuaranteedPokemonCatching();

         }

     }

 

@@ -2158,6 +2177,27 @@ public class Gen1RomHandler extends AbstractGBCRomHandler {
         }

     }

 

+    private void enableGuaranteedPokemonCatching() {

+        int offset = find(rom, Gen1Constants.guaranteedCatchPrefix);

+        if (offset > 0) {

+            offset += Gen1Constants.guaranteedCatchPrefix.length() / 2; // because it was a prefix

+

+            // The game ensures that the Master Ball always catches a Pokemon by running the following code:

+            // ; Get the item ID.

+            //  ld hl, wcf91

+            //  ld a, [hl]

+            //

+            // ; The Master Ball always succeeds.

+            //  cp MASTER_BALL

+            //  jp z, .captured

+            // By making the jump here unconditional, we can ensure that catching always succeeds no

+            // matter the ball type. We check that the original condition is present just for safety.

+            if (rom[offset] == (byte)0xCA) {

+                rom[offset] = (byte)0xC3;

+            }

+        }

+    }

+

     private boolean genericIPSPatch(String ctName) {

         String patchName = romEntry.tweakFiles.get(ctName);

         if (patchName == null) {