Add more math utilities

Source/Engine/Core/Math/CollisionsHelper.cpp

@@ -1437,6 +1437,16 @@ bool CollisionsHelper::LineIntersectsRect(const Vector2& p1, const Vector2& p2,
     return (topoverlap < botoverlap) && (!((botoverlap < t) || (topoverlap > b)));*/
 }
 
+Vector2 CollisionsHelper::LineHitsBox(const Vector3& lineStart, const Vector3& lineEnd, const Vector3& boxMin, const Vector3& boxMax)
+{
+    const Vector3 invDirection = 1.0f / (lineEnd - lineStart);
+    const Vector3 enterIntersection = (boxMin - lineStart) * invDirection;
+    const Vector3 exitIntersection = (boxMax - lineStart) * invDirection;
+    const Vector3 minIntersections = Vector3::Min(enterIntersection, exitIntersection);
+    const Vector3 maxIntersections = Vector3::Max(enterIntersection, exitIntersection);
+    return Vector2(Math::Saturate(minIntersections.MaxValue()), Math::Saturate(maxIntersections.MinValue()));
+}
+
 bool CollisionsHelper::IsPointInTriangle(const Vector2& point, const Vector2& a, const Vector2& b, const Vector2& c)
 {
     const Vector2 an = a - point;

Source/Engine/Core/Math/CollisionsHelper.h

@@ -569,6 +569,12 @@ public:
     /// <returns>True if line intersects with the rectangle</returns>
     static bool LineIntersectsRect(const Vector2& p1, const Vector2& p2, const Rectangle& rect);
 
+    // Hits axis-aligned box (boxMin, boxMax) with a line (lineStart, lineEnd).
+    // Returns the intersections on the line (x - closest, y - furthest).
+    // Line hits the box if: intersections.x < intersections.y.
+    // Hit point is: hitPoint = lineStart + (lineEnd - lineStart) * intersections.x/y.
+    static Vector2 LineHitsBox(const Vector3& lineStart, const Vector3& lineEnd, const Vector3& boxMin, const Vector3& boxMax);
+
     /// <summary>
     /// Determines whether the given 2D point is inside the specified triangle.
     /// </summary>

Source/Shaders/Math.hlsl

@@ -54,6 +54,21 @@ float4 Square(float4 x)
 	return x * x;
 }
 
+float Min2(float2 x)
+{
+	return min(x.x, x.y);
+}
+
+float Min3(float3 x)
+{
+	return min(x.x, min(x.y, x.z));
+}
+
+float Min4(float4 x)
+{
+	return min(x.x, min(x.y, min(x.z, x.w)));
+}
+
 float Max2(float2 x)
 {
 	return max(x.x, x.y);