Replace mersenne twister (closes #896)

src/main/java/legend/core/Random.java

@@ -0,0 +1,17 @@
+package legend.core;
+
+public class Random extends java.util.Random {
+  /**
+   * Returns the 32 high bits of Stafford variant 4 mix64 function as int.
+   * http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html
+   */
+  private static int mix32(long z) {
+    z = (z ^ (z >>> 33)) * 0x62a9d9ed799705f5L;
+    return (int)(((z ^ (z >>> 28)) * 0xcb24d0a5c88c35b3L) >>> 32);
+  }
+
+  @Override
+  public int nextInt() {
+    return mix32(super.nextInt());
+  }
+}

src/main/java/legend/game/combat/Bttl_800c.java

@@ -1,6 +1,7 @@
 package legend.game.combat;
 
 import legend.core.MathHelper;
+import legend.core.Random;
 import legend.core.gpu.GpuCommandPoly;
 import legend.core.gpu.GpuCommandQuad;
 import legend.core.gpu.RECT;
@@ -69,7 +70,6 @@
 import legend.game.combat.types.CombatantStruct1a8;
 import legend.game.combat.types.DragoonSpells09;
 import legend.game.combat.types.EnemyDrop;
-import legend.game.combat.types.MersenneTwisterSeed;
 import legend.game.combat.ui.BattleDisplayStats144;
 import legend.game.combat.ui.BattleHudCharacterDisplay3c;
 import legend.game.combat.ui.BattleMenuStruct58;
@@ -461,8 +461,7 @@ private Bttl_800c() { }
 
   public static final ArrayRef<UnsignedShortRef> additionNextLevelXp_800fa744 = MEMORY.ref(2, 0x800fa744L, ArrayRef.of(UnsignedShortRef.class, 5, 2, UnsignedShortRef::new));
 
-  /** Mersenne Twister seed */
-  public static final MersenneTwisterSeed seed_800fa754 = MEMORY.ref(4, 0x800fa754L, MersenneTwisterSeed::new);
+  public static final Random seed_800fa754 = new Random();
   /**
    * <ol start="0">
    *   <li>{@link Bttl_800d#renderDiscGradientEffect}</li>
@@ -4489,7 +4488,8 @@ public static FlowControl scriptAllocateFullScreenOverlay(final RunningScript<?
   @Method(0x800cee50L)
   public static FlowControl scriptRand(final RunningScript<?> script) {
     final int min = script.params_20[1].get();
-    script.params_20[0].set((int)(seed_800fa754.advance().get() % (script.params_20[2].get() - min + 1) + min));
+    final int max = script.params_20[2].get();
+    script.params_20[0].set(seed_800fa754.nextInt(min, max));
     return FlowControl.CONTINUE;
   }
 
@@ -4727,7 +4727,7 @@ public static FlowControl FUN_800cfec8(final RunningScript<?> script) {
 
   @Method(0x800cfed0L)
   public static void setMtSeed(final long seed) {
-    seed_800fa754.set(seed ^ 0x75b_d924L);
+    seed_800fa754.setSeed(seed ^ 0x75b_d924L);
   }
 
   @ScriptDescription("Sets the Mersenne Twister random number seed")

src/main/java/legend/game/combat/Bttl_800d.java

@@ -295,16 +295,16 @@ public static FlowControl scriptAllocateProjectileHitEffect(final RunningScript<
       struct.g_36 = script.params_20[3].get() << 8;
       struct.b_38 = script.params_20[4].get() << 8;
 
-      final short x = (short)(seed_800fa754.advance().get() % 301 + 200);
-      final short y = (short)(seed_800fa754.advance().get() % 401 - 300);
-      final short z = (short)(seed_800fa754.advance().get() % 601 - 300);
+      final short x = (short)(seed_800fa754.nextInt(301) + 200);
+      final short y = (short)(seed_800fa754.nextInt(401) - 300);
+      final short z = (short)(seed_800fa754.nextInt(601) - 300);
       struct._24[0].set(x, y, z);
       struct._24[1].set(x, y, z);
 
       struct._04[0].x = 0.0f;
-      struct._04[0].y = seed_800fa754.advance().get() % 101 - 50;
-      struct._04[0].z = seed_800fa754.advance().get() % 101 - 50;
-      struct.frames_44 = (int)(seed_800fa754.advance().get() % 9 + 7);
+      struct._04[0].y = seed_800fa754.nextInt(101) - 50;
+      struct._04[0].z = seed_800fa754.nextInt(101) - 50;
+      struct.frames_44 = seed_800fa754.nextInt(9) + 7;
 
       struct._40 = 0;
       struct._24[1].y += 25.0f;
@@ -436,12 +436,12 @@ public static FlowControl scriptAllocateAdditionSparksEffect(final RunningScript
 
       inst.ticksExisted_00 = 0;
 
-      inst.delay_04 = (byte)(seed_800fa754.advance().get() % (s4 + 1));
-      inst.ticksRemaining_05 = (byte)(seed_800fa754.advance().get() % 9 + 7);
+      inst.delay_04 = (byte)(seed_800fa754.nextInt(s4 + 1));
+      inst.ticksRemaining_05 = (byte)(seed_800fa754.nextInt(9) + 7);
 
       inst.startPos_08.set(inst.delay_04 * s1, 0, 0);
       inst.endPos_18.set(0, 0, 0);
-      inst.speed_28.set((int)seed_800fa754.advance().get() % 201, (int)seed_800fa754.advance().get() % 201 - 100, (int)seed_800fa754.advance().get() % 201 - 100);
+      inst.speed_28.set(seed_800fa754.nextInt(201), seed_800fa754.nextInt(201) - 100, seed_800fa754.nextInt(201) - 100);
       inst.acceleration_38.set(0.0f, 15.0f, 0.0f);
 
       inst.r_40 = script.params_20[2].get() << 8;
@@ -613,11 +613,11 @@ public static FlowControl scriptAllocateAdditionStarburstEffect(final RunningScr
     //LAB_800d1ac4
     for(int rayNum = 0; rayNum < rayCount; rayNum++) {
       rayArray[rayNum].renderRay_00 = true;
-      rayArray[rayNum].angle_02 = MathHelper.psxDegToRad(seed_800fa754.advance().get() % 4097);
+      rayArray[rayNum].angle_02 = seed_800fa754.nextFloat(MathHelper.TWO_PI);
       rayArray[rayNum].unused_04 = 16;
-      rayArray[rayNum].endpointTranslationMagnitude_06 = (short)(seed_800fa754.advance().get() % 31);
-      rayArray[rayNum].endpointTranslationMagnitudeVelocity_08 = (short)(seed_800fa754.advance().get() % 21 + 10);
-      rayArray[rayNum].angleModifier_0a = MathHelper.psxDegToRad(seed_800fa754.advance().get() % 11 - 5);
+      rayArray[rayNum].endpointTranslationMagnitude_06 = (short)(seed_800fa754.nextInt(31));
+      rayArray[rayNum].endpointTranslationMagnitudeVelocity_08 = (short)(seed_800fa754.nextInt(21) + 10);
+      rayArray[rayNum].angleModifier_0a = MathHelper.psxDegToRad(seed_800fa754.nextInt(11) - 5);
       rayArray[rayNum].unused_0c = 0;
     }
 
@@ -995,8 +995,8 @@ public static void monsterDeathEffectTicker(final ScriptState<EffectManagerData6
           objArray[objIndex].destructionState_00 = 1;
           objArray[objIndex].stepCount_01 = 8;
           objArray[objIndex].scaleModifier_04 = 0;
-          objArray[objIndex].scaleModifierVelocity_08 = (int)(seed_800fa754.advance().get() % 49 + 104) / (float)0x1000;
-          objArray[objIndex].angleModifier_0c = MathHelper.psxDegToRad((int)(seed_800fa754.advance().get() % 4097));
+          objArray[objIndex].scaleModifierVelocity_08 = (seed_800fa754.nextInt(49) + 104) / (float)0x1000;
+          objArray[objIndex].angleModifier_0c = seed_800fa754.nextFloat(MathHelper.TWO_PI);
           objArray[objIndex].angleModifierVelocity_10 = 0;
           objArray[objIndex].r_24 = manager._10.colour_1c.x << 8;
           objArray[objIndex].g_26 = manager._10.colour_1c.y << 8;
@@ -1798,7 +1798,7 @@ public static void FUN_800d5ec8(final float x, final float y, final float z, fin
    * @param z 8-bit fixed-point
    */
   @Method(0x800d60b0L)
-  public static void FUN_800d60b0(final float x, final float y, final float z, final int ticks, final int stepSmoothingMode, final float stepZ, final int stepType, BattleObject bobj) {
+  public static void FUN_800d60b0(final float x, final float y, final float z, final int ticks, final int stepSmoothingMode, final float stepZ, final int stepType, final BattleObject bobj) {
     final BattleCamera cam = camera_800c67f0;
 
     cam.viewpointAngleX_ac = calculateCameraValue(false, 1, 0, null);
@@ -1831,7 +1831,7 @@ public static void FUN_800d60b0(final float x, final float y, final float z, fin
    * @param z 8-bit fixed-point
    */
   @Method(0x800d62d8L)
-  public static void FUN_800d62d8(final float x, final float y, final float z, final int ticks, final int stepSmoothingMode, final float stepZ, final int stepType, BattleObject bobj) {
+  public static void FUN_800d62d8(final float x, final float y, final float z, final int ticks, final int stepSmoothingMode, final float stepZ, final int stepType, final BattleObject bobj) {
     final BattleCamera cam = camera_800c67f0;
 
     cam.viewpointBaseTranslation_94.x = calculateCameraValue(false, 4, 0, null);
@@ -1860,7 +1860,7 @@ public static void FUN_800d62d8(final float x, final float y, final float z, fin
    * @param z 8-bit fixed-point
    */
   @Method(0x800d64e4L)
-  public static void FUN_800d64e4(final float x, final float y, final float z, final int ticks, final int stepSmoothingMode, final float stepZ, final int stepType, BattleObject bobj) {
+  public static void FUN_800d64e4(final float x, final float y, final float z, final int ticks, final int stepSmoothingMode, final float stepZ, final int stepType, final BattleObject bobj) {
     final BattleCamera cam = camera_800c67f0;
 
     cam.viewpointAngleX_ac = calculateCameraValue(false, 5, 0, null);