Add primitive growable FloatList/IntList for GL buffer building

CityDoctorParent/Extensions/CityDoctorGUI/src/main/java/de/hft/stuttgart/citydoctor2/gui/gl/FloatList.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import java.util.Arrays;
+
+/** Growable primitive float array to avoid boxing when building large vertex buffers. */
+public class FloatList {
+    private float[] data;
+    private int size;
+
+    public FloatList() { this(1024); }
+    public FloatList(int initialCapacity) { data = new float[Math.max(1, initialCapacity)]; }
+
+    public void add(float v) {
+        ensure(size + 1);
+        data[size++] = v;
+    }
+
+    public void add(float a, float b, float c) {
+        ensure(size + 3);
+        data[size++] = a;
+        data[size++] = b;
+        data[size++] = c;
+    }
+
+    private void ensure(int capacity) {
+        if (capacity > data.length) {
+            int newCap = data.length;
+            while (newCap < capacity) {
+                newCap <<= 1;
+            }
+            data = Arrays.copyOf(data, newCap);
+        }
+    }
+
+    public int size() { return size; }
+
+    public float[] toArray() { return Arrays.copyOf(data, size); }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/java/de/hft/stuttgart/citydoctor2/gui/gl/IntList.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import java.util.Arrays;
+
+/** Growable primitive int array. */
+public class IntList {
+    private int[] data;
+    private int size;
+
+    public IntList() { this(1024); }
+    public IntList(int initialCapacity) { data = new int[Math.max(1, initialCapacity)]; }
+
+    public void add(int v) {
+        if (size + 1 > data.length) {
+            data = Arrays.copyOf(data, data.length << 1);
+        }
+        data[size++] = v;
+    }
+
+    public int get(int index) { return data[index]; }
+
+    public int size() { return size; }
+
+    public int[] toArray() { return Arrays.copyOf(data, size); }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/test/java/de/hft/stuttgart/citydoctor2/gui/gl/FloatListTest.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+public class FloatListTest {
+
+    @Test
+    public void growsBeyondInitialCapacityAndPreservesOrder() {
+        FloatList list = new FloatList(2);
+        for (int i = 0; i < 10; i++) {
+            list.add(i);
+        }
+        assertEquals(10, list.size());
+        float[] expected = {0,1,2,3,4,5,6,7,8,9};
+        assertArrayEquals(expected, list.toArray(), 0.0f);
+    }
+
+    @Test
+    public void addThreeAddsAllInOrder() {
+        FloatList list = new FloatList(1);
+        list.add(1f, 2f, 3f);
+        assertArrayEquals(new float[]{1,2,3}, list.toArray(), 0.0f);
+    }
+}