1 files changed, 46 insertions, 0 deletions
diff --git a/src/main/kotlin/util/math/Projections.kt b/src/main/kotlin/util/math/Projections.kt
new file mode 100644
index 0000000..359b21b
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+++ b/src/main/kotlin/util/math/Projections.kt
@@ -0,0 +1,46 @@
+package moe.nea.firmament.util.math
+
+import kotlin.math.absoluteValue
+import kotlin.math.cos
+import kotlin.math.sin
+import net.minecraft.util.math.Vec2f
+import moe.nea.firmament.util.render.wrapAngle
+
+object Projections {
+	object Two {
+		val ε = 1e-6
+		val π = moe.nea.firmament.util.render.π
+		val τ = 2 * π
+
+		fun isNullish(float: Float) = float.absoluteValue < ε
+
+		fun xInterceptOfLine(origin: Vec2f, direction: Vec2f): Vec2f? {
+			if (isNullish(direction.x))
+				return Vec2f(origin.x, 0F)
+			if (isNullish(direction.y))
+				return null
+
+			val slope = direction.y / direction.x
+			return Vec2f(origin.x - origin.y / slope, 0F)
+		}
+
+		fun interceptAlongCardinal(distanceFromAxis: Float, slope: Float): Float? {
+			if (isNullish(slope))
+				return null
+			return -distanceFromAxis / slope
+		}
+
+		fun projectAngleOntoUnitBox(angleRadians: Double): Vec2f {
+			val angleRadians = wrapAngle(angleRadians)
+			val cx = cos(angleRadians)
+			val cy = sin(angleRadians)
+
+			val ex = 1 / cx.absoluteValue
+			val ey = 1 / cy.absoluteValue
+
+			val e = minOf(ex, ey)
+
+			return Vec2f((cx * e).toFloat(), (cy * e).toFloat())
+		}
+	}
+}