Start improving VolumePositionTranslators

Signed-off-by: Gabriel Harris-Rouquette <[email protected]>

Author: gabizou

src/main/java/org/spongepowered/api/util/rotation/Rotation.java

@@ -27,6 +27,7 @@
 import org.spongepowered.api.registry.DefaultedRegistryValue;
 import org.spongepowered.api.util.Angle;
 import org.spongepowered.api.util.annotation.CatalogedBy;
+import org.spongepowered.math.matrix.Matrix4d;
 
 @CatalogedBy(Rotations.class)
 public interface Rotation extends DefaultedRegistryValue {
@@ -40,4 +41,37 @@ public interface Rotation extends DefaultedRegistryValue {
      */
     Angle angle();
 
+    /**
+     * Gets the {@link Matrix4d 4D rotation matrix} of this rotation.
+     *
+     * <p>Minecraft's coordinate system is different than traditional systems
+     * applying the semantic meaning behind the {@code x} and {@code z} axis.
+     * These natures are described as below:
+     * </p>
+     * <ul>
+     *     <li>The x-axis indicates the <b>east</b> (when positive) or <b>west</b>
+     *     (when negative) of the origin point {@code (0, 0, 0)}</li>
+     *     <li>The z-axis indicates the <b>south</b> (when positive) or <b>north</b>
+     *     (when negative) of the origin point {@code (0, 0, 0)}</li>
+     * </ul>
+     * <p>
+     * These rules differ from traditional coordinate interpretations and
+     * therefore may be unintuitive when a rotation of {@code 90} degrees will
+     * instead rotate the coordinates {@code (1, 1, 1)} across the pivot
+     * {@code (0, 0, 0)}
+     * </p>
+     *
+     * @return The euler matrix that represents this rotation in the X-Z plane.
+     */
+    default Matrix4d toRotationMatrix() {
+        final int cos = (int) Math.round(Math.cos(Math.toRadians(-this.angle().degrees())));
+        final int sin = (int) Math.round(Math.sin(Math.toRadians(-this.angle().degrees())));
+        return Matrix4d.from(
+            cos, 0, sin, 0,
+            0, 1, 0, 0,
+            -sin, 0, cos, 0,
+            0, 0, 0, 1
+        );
+    }
+
 }

src/main/java/org/spongepowered/api/world/volume/archetype/ArchetypeVolume.java

@@ -28,8 +28,7 @@
 import org.spongepowered.api.event.CauseStackManager;
 import org.spongepowered.api.event.EventContextKeys;
 import org.spongepowered.api.event.cause.entity.SpawnType;
-import org.spongepowered.api.util.mirror.Mirror;
-import org.spongepowered.api.util.rotation.Rotation;
+import org.spongepowered.api.util.transformation.Transformation;
 import org.spongepowered.api.world.BlockChangeFlags;
 import org.spongepowered.api.world.server.ServerWorld;
 import org.spongepowered.api.world.volume.archetype.block.entity.BlockEntityArchetypeVolume;
@@ -40,6 +39,7 @@
 import org.spongepowered.api.world.volume.stream.VolumeApplicators;
 import org.spongepowered.api.world.volume.stream.VolumeCollectors;
 import org.spongepowered.api.world.volume.stream.VolumePositionTranslators;
+import org.spongepowered.math.vector.Vector3d;
 import org.spongepowered.math.vector.Vector3i;
 
 import java.util.Objects;
@@ -50,6 +50,17 @@ public interface ArchetypeVolume extends BlockVolume.Modifiable<ArchetypeVolume>
     EntityArchetypeVolume.Modifiable<ArchetypeVolume>,
     BiomeVolume.Modifiable<ArchetypeVolume> {
 
+    ArchetypeVolume transform(Transformation transformation);
+
+    /**
+     * Gets the logical center of a volume, considering the decimal coordinates,
+     * the block's center location would have an offset of {@code 0.5}
+     * @return
+     */
+    default Vector3d logicalCenter() {
+        return this.blockMin().toDouble().add(this.blockSize().toDouble().div(2));
+    }
+
     /**
      * Attempts to apply all of the contents of this
      * {@link ArchetypeVolume volume} onto the target {@link ServerWorld world}

src/main/java/org/spongepowered/api/world/volume/stream/VolumePositionTranslators.java

@@ -25,8 +25,6 @@
 package org.spongepowered.api.world.volume.stream;
 
 import org.spongepowered.api.block.BlockState;
-import org.spongepowered.api.block.entity.BlockEntity;
-import org.spongepowered.api.entity.Entity;
 import org.spongepowered.api.util.rotation.Rotation;
 import org.spongepowered.api.world.volume.Volume;
 import org.spongepowered.math.imaginary.Quaterniond;
@@ -47,29 +45,13 @@ public static <W extends Volume> VolumePositionTranslator<W, BlockState> rotateB
         return VolumePositionTranslators.rotateOn(start, center, rotation, (position, state) -> state.rotate(rotation));
     }
 
-    public static <W extends Volume> VolumePositionTranslator<W, Entity> rotateEntitiesOn(final Vector3i start, final Vector3d center, final Rotation rotation) {
-        return VolumePositionTranslators.rotateOn(start, center, rotation, (position, entity) -> {
-            final Quaterniond q = Quaterniond.fromAngleDegAxis(rotation.angle().degrees(), 0, 1, 0);
-            final Vector3d newPosition = q.rotate(entity.position().sub(center.toDouble())).add(center.toDouble());
-            entity.setRotation(entity.rotation().add(0, (float) rotation.angle().degrees() / 360, 0));
-            entity.setPosition(newPosition);
-            return entity;
-        });
-    }
-
-    public static <W extends Volume> VolumePositionTranslator<W, BlockEntity> rotateBlockEntitiesOn(final Vector3i start, final Vector3i center,
-        final Rotation rotation
-    ) {
-        return VolumePositionTranslators.rotateOn(start, center.toDouble(), rotation, (position, blockEntity) -> blockEntity.rotate(rotation));
-    }
-
     public static <W extends Volume, E> VolumePositionTranslator<W, E> rotateOn(final Vector3i start, final Vector3d center, final Rotation rotation,
         final BiFunction<Vector3i, E, E> elementRotation
     ) {
         return element -> {
             final Quaterniond q = Quaterniond.fromAngleDegAxis(rotation.angle().degrees(), 0, 1, 0);
-            final Vector3i v = q.rotate(element.position().sub(center).toDouble()).toInt().add(center);
-            return VolumeElement.of(element.volume(), elementRotation.apply(element.type()), v);
+            final Vector3i v = q.rotate(center).add(element.position().toDouble().sub(start.toDouble())).round().toInt();
+            return VolumeElement.of(element.volume(), elementRotation.apply(v, element.type()), v);
         };
     }
 
@@ -86,12 +68,5 @@ public static <W extends Volume, E> VolumePositionTranslator<W, E> position(fina
         return element -> VolumeElement.of(element.volume(), element.type(), func.apply(element.position()));
     }
 
-    public static <W extends Volume, E> VolumePositionTranslator<W, E> offsetPosition(final Vector3i origin,
-        Vector3i originalOrigin
-    ) {
-        final Vector3i diff = origin.sub(originalOrigin);
-        return element -> VolumeElement.of(element.volume(), element.type(), element.position().add(diff));
-    }
-
     private VolumePositionTranslators() {}
 }

src/main/java/org/spongepowered/api/world/volume/stream/VolumeStream.java

@@ -82,6 +82,8 @@ default VolumeStream<V, Optional<? extends T>> flatMap(final Function<VolumeElem
         return this.flatMap((volume, value, x, y, z) -> mapper.apply(VolumeElement.of(volume, value, new Vector3i(x, y, z))));
     }
 
+    VolumeStream<V, T> transform(VolumePositionTranslator<V, T> transformer);
+
     long count();
 
     boolean allMatch(VolumePredicate<V, ? super T> predicate);