Misc things (#30)

* match random init

* UnkSystem2_UnkSubSystem1_Derived1 related docs

* match func_ov031_020e9108 and FileSelect_UnkClass7::vfunc_00

* improve func_02017ea4

* rename next functions

* actor rupee improvements

* update gitignore

* fix broken match

* fileselectmain improvements

* fix broken match

* more misc progress

* fix build issues

* fix regressions

include/System/Random.hpp

@@ -1,26 +1,64 @@
 #pragma once
 
 #include "global.h"
+#include "nitro/math.h"
 #include "types.h"
 
 struct Random {
-    /* 00 */ u64 mRandomValue;
+    /* 00 */ u16 mRandomValue[4];
     /* 08 */ u64 mFactor;
     /* 10 */ u64 mAddend;
     /* 18 */
 
     /**
-     * Generate a random number from 0 (inclusive) to `max` (exclusive)
+     * @brief Gets the seed's value
      */
-    u32 Next(u64 min, u64 max) {
-        mRandomValue = mAddend + mFactor * mRandomValue;
-        u64 result;
-        if ((max - min) == 0x100000000) {
-            result = mRandomValue;
-        } else {
-            result = (mRandomValue >> 32) * (max - min);
+    u64 GetRandomValue() {
+        return *(u64 *) this->mRandomValue;
+    }
+
+    /**
+     * @brief Updates the seed's value
+     */
+    void UpdateRandomValue() {
+        *(u64 *) this->mRandomValue = this->mAddend + (this->mFactor * this->GetRandomValue());
+    }
+
+    /**
+     * @brief Generates a random number as a u16
+     */
+    u16 Next16() {
+        this->UpdateRandomValue();
+        return this->GetRandomValue() >> 48;
+    }
+
+    /**
+     * @brief Generates a random number from 0 (inclusive) to `max` (exclusive) as a u32
+     */
+    u32 Next32(u64 min, u64 max) {
+        this->UpdateRandomValue();
+        return (((this->GetRandomValue() >> 32) * (max - min)) >> 32) + min;
+    }
+
+    u32 ConditionalNext32(u32 value) {
+        this->UpdateRandomValue();
+
+        u64 result = this->GetRandomValue() >> 32;
+
+        if (value != 0) {
+            result = (result * value) >> 32;
         }
-        return (result >> 32) + min;
+
+        return result;
+    }
+
+    Vec2us &NextPos(u16 xMax, u16 yMax) {
+        Vec2us pos;
+
+        pos.x = this->Next32(0, xMax);
+        pos.y = this->Next32(0, yMax);
+
+        return pos;
     }
 
     void Init();