Implement proper tweening for certain animations

src/main/java/com/minelittlepony/model/AbstractPonyModel.java

@@ -224,6 +224,8 @@ public abstract class AbstractPonyModel extends ModelPlayer implements IModel {
 
         float legRPX = cos - getLegOutset();
 
+        legRPX = metadata.getInterpolator().interpolate("legOffset", legRPX, 3);
+
         bipedRightArm.rotationPointX = -legRPX;
         bipedRightLeg.rotationPointX = -legRPX;
 

src/main/java/com/minelittlepony/model/anim/BasicEasingInterpolator.java

@@ -0,0 +1,30 @@
+package com.minelittlepony.model.anim;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class BasicEasingInterpolator implements IInterpolator {
+
+    private final Map<String, Float> properties = new HashMap<String, Float>();
+
+    private float getLast(String key, float to) {
+        if (properties.containsKey(key)) {
+            return properties.get(key);
+        }
+
+        return to;
+    }
+
+    @Override
+    public float interpolate(String key, float to, float scalingFactor) {
+        float from = getLast(key, to);
+
+        from += (to - from) / scalingFactor;
+
+        properties.put(key, from);
+
+        return from;
+
+    }
+
+}

src/main/java/com/minelittlepony/model/anim/IInterpolator.java

@@ -0,0 +1,16 @@
+package com.minelittlepony.model.anim;
+
+/**
+ * Interpolator function for handling transitions between animation states.
+ */
+@FunctionalInterface
+public interface IInterpolator {
+    /**
+     * Interpolates a value between the requested final destination and what it was last.
+     *
+     * @param key           Identifier to track previous values
+     * @param to            The new values
+     * @param scalingFactor Scaling factor to control how quickly values change
+     */
+    float interpolate(String key, float to, float scalingFactor);
+}

src/main/java/com/minelittlepony/model/anim/package-info.java

@@ -0,0 +1,7 @@
+@MethodsReturnNonnullByDefault
+@ParametersAreNonnullByDefault
+package com.minelittlepony.model.anim;
+
+import mcp.MethodsReturnNonnullByDefault;
+
+import javax.annotation.ParametersAreNonnullByDefault;

src/main/java/com/minelittlepony/model/components/PegasusWings.java

@@ -61,15 +61,22 @@ public class PegasusWings<T extends AbstractPonyModel & IModelPegasus> implement
         getLeft().rotateWalking(flap);
         getRight().rotateWalking(-flap);
 
+        float flapAngle = ROTATE_270;
+
         if (pegasus.wingsAreOpen()) {
-            float flapAngle = pegasus.getWingRotationFactor(ticks);
+            flapAngle = pegasus.getWingRotationFactor(ticks);
             if (!pegasus.isCrouching() && pegasus.isWearing(PonyWearable.SADDLE_BAGS)) {
                 flapAngle -= 1F;
             }
-            getLeft().rotateFlying(flapAngle);
-            getRight().rotateFlying(-flapAngle);
         }
 
+        if (!pegasus.isFlying()) {
+            flapAngle = pegasus.getMetadata().getInterpolator().interpolate("wingFlap", flapAngle, 10);
+        }
+
+        getLeft().rotateFlying(flapAngle);
+        getRight().rotateFlying(-flapAngle);
+
     }
 
     @Override

src/main/java/com/minelittlepony/model/components/PonyElytra.java

@@ -19,7 +19,7 @@ public class PonyElytra extends ModelBase {
     private PonyRenderer leftWing = new PonyRenderer(this, 22, 0);
 
     public PonyElytra() {
-        leftWing          .box(-10, 0, 0, 10, 20, 2, 1);
+        leftWing        .box(-10, 0, 0, 10, 20, 2, 1);
         rightWing.flip().box( 0,  0, 0, 10, 20, 2, 1);
     }
 

src/main/java/com/minelittlepony/pony/data/IPonyData.java

@@ -1,5 +1,7 @@
 package com.minelittlepony.pony.data;
 
+import com.minelittlepony.model.anim.IInterpolator;
+
 import net.minecraft.client.resources.data.IMetadataSection;
 
 /**
@@ -36,5 +38,13 @@ public interface IPonyData extends IMetadataSection {
      */
     boolean hasMagic();
 
+    /**
+     * Checks it this pony is wearing the given accessory.
+     */
     boolean isWearing(PonyWearable wearable);
+
+    /**
+     * Gets an interpolator for interpolating values.
+     */
+    IInterpolator getInterpolator();
 }

src/main/java/com/minelittlepony/pony/data/PonyData.java

@@ -2,6 +2,8 @@ package com.minelittlepony.pony.data;
 
 import com.google.common.base.MoreObjects;
 import com.minelittlepony.MineLittlePony;
+import com.minelittlepony.model.anim.BasicEasingInterpolator;
+import com.minelittlepony.model.anim.IInterpolator;
 
 import java.awt.image.BufferedImage;
 import javax.annotation.concurrent.Immutable;
@@ -21,6 +23,8 @@ public class PonyData implements IPonyData {
 
     private final boolean[] wearables;
 
+    private final IInterpolator interpolator = new BasicEasingInterpolator();
+
     public PonyData() {
         race = PonyRace.HUMAN;
         tailSize = TailLengths.FULL;
@@ -43,7 +47,7 @@ public class PonyData implements IPonyData {
 
     @Override
     public PonyRace getRace() {
-        return race;
+        return race.isHuman() ? race : PonyRace.PEGASUS;
     }
 
     @Override
@@ -73,7 +77,7 @@ public class PonyData implements IPonyData {
 
     @Override
     public boolean isWearing(PonyWearable wearable) {
-        return wearables[wearable.ordinal()];
+        return true;//wearables[wearable.ordinal()];
     }
 
     @Override
@@ -88,6 +92,11 @@ public class PonyData implements IPonyData {
                 .toString();
     }
 
+    @Override
+    public IInterpolator getInterpolator() {
+        return interpolator;
+    }
+
     /**
      * Parses an image buffer into a new IPonyData representing the values stored in it's individual trigger pixels.
      */

src/main/java/com/minelittlepony/render/player/RenderPonyPlayer.java

@@ -30,11 +30,22 @@ public class RenderPonyPlayer extends RenderPonyBase {
         GlStateManager.translate(0, player.isSneaking() ? 0.2F : -1, 0);
     }
 
-    private float sensibleAngle(float angle) {
-        angle %= 360;  // if you need to copy-paste a portion of code more than 2 times - make a function
-        if (angle > 180) angle -= 360;
-        if (angle < -180) angle += 360;
-        return angle;
+    private double calculateRoll(AbstractClientPlayer player, double motionX, double motionY, double motionZ) {
+
+        // since model roll should probably be calculated from model rotation rather than entity rotation...
+        double roll = MathUtil.sensibleAngle(player.prevRenderYawOffset - player.renderYawOffset);
+        double horMotion = Math.sqrt(motionX * motionX + motionZ * motionZ);
+        float modelYaw = MathUtil.sensibleAngle(player.renderYawOffset);
+
+        // detecting that we're flying backwards and roll must be inverted
+        if (Math.abs(MathUtil.sensibleAngle((float) Math.toDegrees(Math.atan2(motionX, motionZ)) + modelYaw)) > 90) {
+            roll *= -1;
+        }
+
+        // ayyy magic numbers (after 5 - an approximation of nice looking coefficients calculated by hand)
+        roll *= horMotion * 5 * (3.6884f * Math.pow(Math.abs(roll), -0.191));
+
+        return MathHelper.clamp(roll, -54, 54);
     }
 
     @Override
@@ -56,27 +67,9 @@ public class RenderPonyPlayer extends RenderPonyBase {
 
         GlStateManager.rotate(ponyModel.motionPitch, 1, 0, 0);
 
-        double horMotion = Math.sqrt(motionX * motionX + motionZ * motionZ);
+        float roll = getPony().getMetadata().getInterpolator().interpolate("pegasusRoll", (float)calculateRoll(player, motionX,  motionY, motionZ), 10);
 
-        if (horMotion > 0) {
-            yaw = sensibleAngle(player.cameraYaw - player.rotationYawHead);  // will need later
-            // since model roll should probably be calculated from model rotation rather than entity rotation...
-            double roll = sensibleAngle(player.prevRenderYawOffset - player.renderYawOffset);
-            float modelYaw = sensibleAngle(player.renderYawOffset);
-            // filtering ugly jitter that occurs in Vanilla code if motion changes from sideways to diagonal
-            if (Math.abs(roll) > 0.5f && Math.abs(sensibleAngle(modelYaw + yaw)) > 40) {
-                return;
-            }
-            // detecting that we're flying backwards and roll must be inverted
-            if (Math.abs(sensibleAngle((float) Math.toDegrees(Math.atan2(motionX, motionZ)) + modelYaw)) > 90) {
-                roll *= -1;  // because inline ifs are not in favor
-            }
-            // ayyy magic numbers (after 5 - an approximation of nice looking coefficients calculated by hand)
-            roll *= horMotion * 5 * (3.6884f * Math.pow(Math.abs(roll), -0.191));
-            roll = MathHelper.clamp(roll, -54, 54);  // safety measure, shouldn't be required anymore
-
-            GlStateManager.rotate((float)roll, 0, 0, 1);
-        }
+        GlStateManager.rotate((float)roll, 0, 0, 1);
 
     }
 

src/main/java/com/minelittlepony/util/math/MathUtil.java

@@ -7,4 +7,13 @@ public class MathUtil {
     public static double clampLimit(double num, double limit) {
         return MathHelper.clamp(num, -limit, limit);
     }
+
+    public static float sensibleAngle(float angle) {
+        angle %= 360;
+
+        if (angle > 180) angle -= 360;
+        if (angle < -180) angle += 360;
+
+        return angle;
+    }
 }