When you're sick and tired of staring at this unreadable code

src/main/java/com/minelittlepony/model/armour/ModelPonyArmor.java

@@ -126,8 +126,8 @@ public class ModelPonyArmor extends ModelMobPony {
         bipedRightArm = new PonyRenderer(this, 0, 16);
         bipedRightLeg = new PonyRenderer(this, 0, 16);
 
-        bipedLeftArm = new PonyRenderer(this, 0, 16).mirror();
+        bipedLeftArm = new PonyRenderer(this, 0, 16).flipX();
-        bipedLeftLeg = new PonyRenderer(this, 0, 16).mirror();
+        bipedLeftLeg = new PonyRenderer(this, 0, 16).flipX();
 
         unicornArmRight = new PonyRenderer(this, 0, 16);
         unicornArmLeft = new PonyRenderer(this, 0, 16);
@@ -175,7 +175,7 @@ public class ModelPonyArmor extends ModelMobPony {
                        .box(-2, -6, -2, 4, 12, 4, stretch);
         rightLegging.offset(THIRDP_ARM_CENTRE_X, THIRDP_ARM_CENTRE_Y, THIRDP_ARM_CENTRE_Z)
                        .around(-3, yOffset, 0)
-              .mirror().box(-2, -6, -2, 4, 12, 4, stretch);
+              .flipX().box(-2, -6, -2, 4, 12, 4, stretch);
     }
 
     protected void syncLegs() {

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

@@ -20,7 +20,7 @@ public class PonyElytra extends ModelBase {
 
     public PonyElytra() {
         leftWing          .box(-10, 0, 0, 10, 20, 2, 1);
-        rightWing.mirror().box( 0,  0, 0, 10, 20, 2, 1);
+        rightWing.flipX().box( 0,  0, 0, 10, 20, 2, 1);
     }
 
     @Override

src/main/java/com/minelittlepony/model/player/ModelEarthPony.java

@@ -514,7 +514,7 @@ public class ModelEarthPony extends AbstractPonyModel {
                                  .box(-4, -4, -4, 8, 8, 8, stretch)
                                  .tex(12, 16)
                                  .box(-4, -6, 1, 2, 2, 2, stretch)
-                                 .mirror()
+                                 .flipX()
                                  .box(2, -6, 1, 2, 2, 2, stretch);
 
         ((PonyRenderer)bipedHeadwear).offset(HEAD_CENTRE_X, HEAD_CENTRE_Y, HEAD_CENTRE_Z)

src/main/java/com/minelittlepony/render/AbstractPonyRenderer.java

@@ -43,7 +43,7 @@ public abstract class AbstractPonyRenderer<T extends AbstractPonyRenderer<T>> ex
     /**
      * Flips the mirror flag. All faces are mirrored until this is called again.
      */
-    public T mirror() {
+    public T flipX() {
         return mirror(!mirror);
     }
 

src/main/java/com/minelittlepony/render/plane/ModelPlane.java

@@ -1,75 +1,73 @@
 package com.minelittlepony.render.plane;
 
-import net.minecraft.client.model.ModelBox;
-import net.minecraft.client.model.PositionTextureVertex;
-import net.minecraft.client.model.TexturedQuad;
 import net.minecraft.client.renderer.BufferBuilder;
 
 import javax.annotation.Nonnull;
 
-public class ModelPlane extends ModelBox {
+import com.minelittlepony.util.coordinates.*;
 
-    private TexturedQuad quad;
+public class ModelPlane extends Box<PlaneRenderer> {
+
+    private Quad quad;
 
     public boolean hidden = false;
 
-    public ModelPlane(PlaneRenderer renderer, int textureX, int textureY, float x, float y, float z, int w, int h, int d, float scale, Face face) {
+    public ModelPlane(PlaneRenderer renderer, int textureX, int textureY, float xMin, float yMin, float zMin, int w, int h, int d, float scale, Face face) {
-        super(renderer, textureX, textureY, x, y, z, w, h, d, scale, false);
+        super(renderer, textureX, textureY, xMin, yMin, zMin, w, h, d, scale, false);
 
-        float x2 = x + w + scale;
+        float xMax = xMin + w + scale;
-        float y2 = y + h + scale;
+        float yMax = yMin + h + scale;
-        float z2 = z + d + scale;
+        float zMax = zMin + d + scale;
 
-        x -= scale;
+        xMin -= scale;
-        y -= scale;
+        yMin -= scale;
-        z -= scale;
+        zMin -= scale;
 
         if (renderer.mirror) {
-            float v = x2;
+            float v = xMax;
-            x2 = x;
+            xMax = xMin;
-            x = v;
+            xMin = v;
         }
 
         if (renderer.mirrory) {
-            float v = y2;
+            float v = yMax;
-            y2 = y;
+            yMax = yMin;
-            y = v;
+            yMin = v;
         }
 
         if (renderer.mirrorz) {
-            float v = z2;
+            float v = zMax;
-            z2 = z;
+            zMax = zMin;
-            z = v;
+            zMin = v;
-
         }
 
         // w:west e:east d:down u:up s:south n:north
-        PositionTextureVertex wds = new PositionTextureVertex(x , y , z , 0, 0);
+        Vertex wds = vert(xMin , yMin , zMin , 0, 0);
-        PositionTextureVertex eds = new PositionTextureVertex(x2, y , z , 0, 8);
+        Vertex eds = vert(xMax, yMin , zMin , 0, 8);
-        PositionTextureVertex eus = new PositionTextureVertex(x2, y2, z , 8, 8);
+        Vertex eus = vert(xMax, yMax, zMin , 8, 8);
-        PositionTextureVertex wus = new PositionTextureVertex(x , y2, z , 8, 0);
+        Vertex wus = vert(xMin , yMax, zMin , 8, 0);
-        PositionTextureVertex wdn = new PositionTextureVertex(x , y , z2, 0, 0);
+        Vertex wdn = vert(xMin , yMin , zMax, 0, 0);
-        PositionTextureVertex edn = new PositionTextureVertex(x2, y , z2, 0, 8);
+        Vertex edn = vert(xMax, yMin , zMax, 0, 8);
-        PositionTextureVertex eun = new PositionTextureVertex(x2, y2, z2, 8, 8);
+        Vertex eun = vert(xMax, yMax, zMax, 8, 8);
-        PositionTextureVertex wun = new PositionTextureVertex(x , y2, z2, 8, 0);
+        Vertex wun = vert(xMin , yMax, zMax, 8, 0);
 
-        if (face == Face.EAST) { // North/Front (was East)
+        if (face == Face.EAST) {
-            quad = new TexturedQuad(new PositionTextureVertex[]{edn, eds, eus, eun}, textureX, textureY, textureX + d, textureY + h, renderer.textureWidth, renderer.textureHeight);
+            quad = quad(textureX, d, textureY, h, edn, eds, eus, eun);
         }
-        if (face == Face.WEST) { // South/Back (was West)
+        if (face == Face.WEST) {
-            quad = new TexturedQuad(new PositionTextureVertex[]{wds, wdn, wun, wus}, textureX, textureY, textureX + d, textureY + h, renderer.textureWidth, renderer.textureHeight);
+            quad = quad(textureX, d, textureY, h, wds, wdn, wun, wus);
         }
-        if (face == Face.UP) { // Up
+        if (face == Face.UP) {
-            quad = new TexturedQuad(new PositionTextureVertex[]{edn, wdn, wds, eds}, textureX, textureY, textureX + w, textureY + d, renderer.textureWidth, renderer.textureHeight);
+            quad = quad(textureX, w, textureY, h, edn, wdn, wds, eds);
         }
-        if (face == Face.DOWN) { // Down
+        if (face == Face.DOWN) {
-            quad = new TexturedQuad(new PositionTextureVertex[]{eus, wus, wun, eun}, textureX, textureY, textureX + w, textureY + d, renderer.textureWidth, renderer.textureHeight);
+            quad = quad(textureX, w, textureY, d, eus, wus, wun, eun);
         }
         if (face == Face.SOUTH) { // East/Left (was South)
-            quad = new TexturedQuad(new PositionTextureVertex[]{eds, wds, wus, eus}, textureX, textureY, textureX + w, textureY + h, renderer.textureWidth, renderer.textureHeight);
+            quad = quad(textureX, w, textureY, h, eds, wds, wus, eus);
         }
         if (face == Face.NORTH) { // West/Right (was North)
-            quad = new TexturedQuad(new PositionTextureVertex[]{wdn, edn, eun, wun}, textureX, textureY, textureX + w, textureY + h, renderer.textureWidth, renderer.textureHeight);
+            quad = quad(textureX, w, textureY, h, wdn, edn, eun, wun);
         }
 
         if (renderer.mirror || renderer.mirrory || renderer.mirrorz) {

src/main/java/com/minelittlepony/util/coordinates/Box.java

@@ -0,0 +1,36 @@
+package com.minelittlepony.util.coordinates;
+
+import net.minecraft.client.model.ModelBox;
+import net.minecraft.client.model.ModelRenderer;
+
+public abstract class Box<T extends ModelRenderer> extends ModelBox {
+
+    protected final T parent;
+
+    public Box(T renderer, int texU, int texV, float x, float y, float z, int dx, int dy, int dz, float delta) {
+        super(renderer, texU, texV, x, y, z, dx, dy, dz, delta);
+        parent = renderer;
+    }
+
+    public Box(T renderer, int texU, int texV, float x, float y, float z, int dx, int dy, int dz, float delta, boolean mirror) {
+        super(renderer, texU, texV, x, y, z, dx, dy, dz, delta, mirror);
+        parent = renderer;
+    }
+
+    /**
+     * Creates a new vertex mapping the given (x, y, z) coordinates to a texture offset.
+     */
+    protected Vertex vert(float x, float y, float z, int texX, int texY) {
+        return new Vertex(x, y, z, texX, texY);
+    }
+
+    /**
+     * Creates a new quad with the given spacial vertices.
+     */
+    protected Quad quad(int startX, int width, int startY, int height, Vertex ...verts) {
+        return new Quad(verts,
+                startX,         startY,
+                startX + width, startY + height,
+                parent.textureWidth, parent.textureHeight);
+    }
+}

src/main/java/com/minelittlepony/util/coordinates/Quad.java

@@ -0,0 +1,10 @@
+package com.minelittlepony.util.coordinates;
+
+import net.minecraft.client.model.TexturedQuad;
+
+public class Quad extends TexturedQuad {
+
+    public Quad(Vertex[] vertices, int texcoordU1, int texcoordV1, int texcoordU2, int texcoordV2, float textureWidth, float textureHeight) {
+        super(vertices, texcoordU1, texcoordV1, texcoordU2, texcoordV2, textureWidth, textureHeight);
+    }
+}

src/main/java/com/minelittlepony/util/coordinates/Vertex.java

@@ -0,0 +1,27 @@
+package com.minelittlepony.util.coordinates;
+
+import net.minecraft.client.model.PositionTextureVertex;
+
+public class Vertex extends PositionTextureVertex {
+
+    public Vertex(float x, float y, float z, int texX, int texY) {
+        super(x, y, z, texX, texY);
+    }
+
+    public Vertex(Vertex old, float texX, float texY) {
+        super(old, texX, texY);
+    }
+
+    public Vertex setTexturePosition(float texX, float texY) {
+        texturePositionX = texX;
+        texturePositionY = texY;
+        return this;
+    }
+
+    /**
+     * Creates a new vertex mapping the given (x, y, z) coordinates to a texture offset.
+     */
+    public static Vertex vert(float x, float y, float z, int texX, int texY) {
+        return new Vertex(x, y, z, texX, texY);
+    }
+}