Modify look (#848)

* Added modify(e,'look',...

* Added modify(e,'look',...

* Not change yaw and pitch if vector length is 0 or straight up/down

* Added to docs

* Update docs/scarpet/api/Entities.md

Co-authored-by: gnembon <41132274+gnembon@users.noreply.github.com>

docs/scarpet/api/Entities.md

@@ -589,6 +589,12 @@ Changes entity's location in the specified direction.
 
 Changes entity's pitch or yaw angle.
 
+### `modify(e, 'look', x, y, z), modify(e, 'look', [x,y,z] )`
+
+Sets entity's 3d vector where the entity is looking.
+For cases where the vector has a length of 0, yaw and pitch won't get changed.
+When pointing straight up or down, yaw will stay the same.
+
 ### `modify(e, 'head_yaw', angle)`, `modify(e, 'body_yaw', angle)`
 
 For living entities, controls their head and body yaw angle.

src/main/java/carpet/script/value/EntityValue.java

@@ -1034,7 +1034,22 @@ public class EntityValue extends Value
             updatePosition(e, e.getX(), e.getY(), e.getZ(), e.yaw, MathHelper.clamp((float)NumericValue.asNumber(v).getDouble(), -90, 90));
         });
 
-        //"look"
+        put("look", (e, v) -> {
+            if (!(v instanceof ListValue)) throw new InternalExpressionException("Expected a list of 3 parameters as a second argument");
+            List<Value> vec = ((ListValue)v).getItems();
+            float x = NumericValue.asNumber(vec.get(0)).getFloat();
+            float y = NumericValue.asNumber(vec.get(1)).getFloat();
+            float z = NumericValue.asNumber(vec.get(2)).getFloat();
+            float l = MathHelper.sqrt(x*x + y*y + z*z);
+            if(l==0) return;
+            x /= l;
+            y /= l;
+            z /= l;
+            float pitch = (float) -Math.asin(y) / 0.017453292F;
+            float yaw = (float) (x==0 && z==0 ? e.yaw : MathHelper.atan2(-x,z) / 0.017453292F);
+            updatePosition(e, e.getX(), e.getY(), e.getZ(), yaw, pitch);
+        });
+
         //"turn"
         //"nod"