optimize EntityRotation::front, tests

src/main/java/de/bixilon/minosoft/data/entities/EntityRotation.kt

@@ -24,11 +24,17 @@ data class EntityRotation(
     val pitch: Float,
 ) {
     val front: Vec3
-        get() = Vec3(
-            (-yaw).rad.sin * pitch.rad.cos,
-            (-pitch).rad.sin,
-            (-yaw).rad.cos * pitch.rad.cos
+        get() {
+            val pitchRad = pitch.rad
+            val pitchCos = pitchRad.cos
+            val yawRad = -yaw.rad
+
+            return Vec3(
+                yawRad.sin * pitchCos,
+                -pitchRad.sin,
+                yawRad.cos * pitchCos
             ).normalize()
+        }
 
     override fun toString(): String {
         return "(yaw=$yaw, pitch=$pitch)"

src/test/java/de/bixilon/minosoft/data/entities/EntityRotationTest.kt

@@ -13,6 +13,7 @@
 
 package de.bixilon.minosoft.data.entities
 
+import de.bixilon.kotlinglm.vec3.Vec3
 import de.bixilon.minosoft.data.entities.EntityRotation.Companion.interpolateYaw
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Test
@@ -53,4 +54,22 @@ class EntityRotationTest {
     fun interpolation7() {
         assertEquals(150.0f, interpolateYaw(0.5f, 110.0f, -170.0f))
     }
+
+    @Test
+    fun front1() {
+        val front = EntityRotation(10.0f, 20.0f).front
+        assertEquals(front, Vec3(-0.16317593, -0.34202015, 0.92541665))
+    }
+
+    @Test
+    fun front2() {
+        val front = EntityRotation(-10.0f, -20.0f).front
+        assertEquals(front, Vec3(0.16317593, 0.34202015, 0.92541665))
+    }
+
+    @Test
+    fun front3() {
+        val front = EntityRotation(-80.0f, 80.0f).front
+        assertEquals(front, Vec3(0.1710101, -0.9848077, 0.030153705))
+    }
 }