Use next higher integral factor as well.

When seeking scaled resources, try scaling a slightly higher factor resource
down before attempting to scale a slightly lower factor resource up.

core/src/playn/core/Scale.java

@@ -105,16 +105,18 @@ public float roundToNearestPixel(float length) {
   }
 
   /**
-   * Returns an ordered series of scaled resources to try when loading an asset. The highest
-   * (presumably native) resolution will be tried first, then that will be stepped down to all
-   * whole integers less than the native resolution. Often this is simply {@code 2, 1}, but on a
-   * Retina iPad, it could be {@code 4, 3, 2, 1}, and on Android devices it may often be something
-   * like {@code 3, 2, 1} or {@code 2.5, 2, 1}.
+   * Returns an ordered series of scaled resources to try when loading an asset. The native
+   * resolution will be tried first, then that will be rounded up to the nearest whole integer and
+   * stepped down through all whole integers to {@code 1}. If the native scale factor is {@code 2},
+   * this will yield {@code 2, 1}. If the native scale factor is {@code 4}, this will yield
+   * {@code 4, 3, 2, 1}. Android devices often have fractional scale factors, which demonstrates
+   * the rounding up then back down approach: a native scale factor of {@code 2.5} would yield
+   * {@code 2.5, 3, 2, 1}.
    */
   public List<ScaledResource> getScaledResources(String path) {
     List<ScaledResource> rsrcs = new ArrayList<ScaledResource>();
     rsrcs.add(new ScaledResource(this, computePath(path, factor)));
-    for (float rscale = MathUtil.ifloor(factor); rscale > 1; rscale -= 1) {
+    for (float rscale = MathUtil.iceil(factor); rscale > 1; rscale -= 1) {
       if (rscale != factor) rsrcs.add(
         new ScaledResource(new Scale(rscale), computePath(path, rscale)));
     }

core/tests/playn/core/ScaleTest.java

@@ -0,0 +1,38 @@
+/**
+ * Copyright 2010-2015 The PlayN Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package playn.core;
+
+import java.util.List;
+import org.junit.Test;
+import pythagoras.f.MathUtil;
+import static org.junit.Assert.*;
+
+public class ScaleTest {
+
+  private void assertScalesMatch (List<Scale.ScaledResource> rsrcs, float... scales) {
+    int ii = 0;
+    assertEquals("Scale count does not match resource count", scales.length, rsrcs.size());
+    for (Scale.ScaledResource rsrc : rsrcs) {
+      assertEquals(rsrc.scale.factor, scales[ii++], MathUtil.EPSILON);
+    }
+  }
+
+  @Test
+  public void testScaledResources () {
+    assertScalesMatch(new Scale(2).getScaledResources("test.png"), 2, 1);
+    assertScalesMatch(new Scale(4).getScaledResources("test.png"), 4, 3, 2, 1);
+    assertScalesMatch(new Scale(2.5f).getScaledResources("test.png"), 2.5f, 3, 2, 1);
+    assertScalesMatch(new Scale(1.5f).getScaledResources("test.png"), 1.5f, 2, 1);
+  }
+}