bgc-net/BasicGeometry/Vector2FP32.cs

/*
 * Author: Andrey Pokidov
 * License: Apache-2.0
 * Date: 1 Feb 2019
 */

namespace BasicGeometry
{
    public struct Vector2FP32
    {
        public static readonly Vector2FP32 ZERO = new Vector2FP32(0.0f, 0.0f);

        public float x1 = 0.0f;
        public float x2 = 0.0f;

        public Vector2FP32(float x1, float x2)
        {
            this.x1 = x1;
            this.x2 = x2;
        }

        public Vector2FP32(in Vector2FP32 vector)
        {
            this.x1 = vector.x1;
            this.x2 = vector.x2;
        }

        public Vector2FP32(in Vector2FP64 vector)
        {
            this.x1 = (float)vector.x1;
            this.x2 = (float)vector.x2;
        }

        public readonly float GetSquareModulus()
        {
            return this.x1 * this.x1 + this.x2 * this.x2;
        }

        public readonly float GetModulus()
        {
            return MathF.Sqrt(this.GetSquareModulus());
        }

        public int Normalize()
        {
            float squareModulus = this.GetSquareModulus();

            if (UtilityFP32.IsSqareUnit(squareModulus))
            {
                return 1;
            }

            if (squareModulus <= UtilityFP32.SQUARE_EPSYLON)
            {
                this.Reset();
                return 0;
            }

            float multiplier = MathF.Sqrt(1.0f / squareModulus);

            this.x1 *= multiplier;
            this.x2 *= multiplier;

            return 1;
        }

        public void Reverse()
        {
            this.x1 = -this.x1;
            this.x2 = -this.x2;
        }

        public readonly bool IsZero()
        {
            return this.GetSquareModulus() <= UtilityFP32.SQUARE_EPSYLON;
        }

        public readonly bool IsUnit()
        {
            return UtilityFP32.IsSqareUnit(this.GetSquareModulus());
        }

        public void Reset()
        {
            this.x1 = 0.0f;
            this.x2 = 0.0f;
        }

        public void SetValues(float x1, float x2)
        {
            this.x1 = x1;
            this.x2 = x2;
        }

        public void SetValues(in Vector2FP32 vector)
        {
            this.x1 = vector.x1;
            this.x2 = vector.x2;
        }

        public void SetValues(in Vector2FP64 vector)
        {
            this.x1 = (float)vector.x1;
            this.x2 = (float)vector.x2;
        }

        public void SetReverseOf(in Vector2FP32 vector)
        {
            this.x1 = -vector.x1;
            this.x2 = -vector.x2;
        }

        public void SetReverseOf(in Vector2FP64 vector)
        {
            this.x1 = -(float)vector.x1;
            this.x2 = -(float)vector.x2;
        }

        public void AppendScaled(Vector2FP32 summand, float scale)
        {
            this.x1 += summand.x1 * scale;
            this.x2 += summand.x2 * scale;
        }
        
        public readonly override string ToString()
        {
            return String.Format("SPVector2({0}, {1})", this.x1, this.x2);
        }

        public static void Add(in Vector2FP32 vector1, in Vector2FP32 vector2, out Vector2FP32 sum)
        {
            sum.x1 = vector1.x1 + vector2.x1;
            sum.x2 = vector1.x2 + vector2.x2;
        }

        public static void Subtract(in Vector2FP32 minuend, in Vector2FP32 subtrahend, out Vector2FP32 difference)
        {
            difference.x1 = minuend.x1 - subtrahend.x1;
            difference.x2 = minuend.x2 - subtrahend.x2;
        }

        public static void Multiply(in Vector2FP32 multiplicand, float multiplier, out Vector2FP32 product)
        {
            product.x1 = multiplicand.x1 * multiplier;
            product.x2 = multiplicand.x2 * multiplier;
        }

        public static void Divide(in Vector2FP32 dividend, float divisor, out Vector2FP32 quotient)
        {
            Multiply(dividend, 1.0f / divisor, out quotient);
        }

        public static void GetMean2(in Vector2FP32 vector1, in Vector2FP32 vector2, out Vector2FP32 result)
        {
            result.x1 = (vector1.x1 + vector2.x1) * 0.5f;
            result.x2 = (vector1.x2 + vector2.x2) * 0.5f;
        }

        public static void GetMean3(in Vector2FP32 vector1, in Vector2FP32 vector2, in Vector2FP32 vector3, out Vector2FP32 result)
        {
            result.x1 = (vector1.x1 + vector2.x1 + vector3.x1) * UtilityFP32.ONE_THIRD;
            result.x2 = (vector1.x2 + vector2.x2 + vector3.x2) * UtilityFP32.ONE_THIRD;
        }

        public static float GetScalarProduct(in Vector2FP32 vector1, in Vector2FP32 vector2)
        {
            return vector1.x1 * vector2.x1 + vector1.x2 * vector2.x2;
        }
 
        public static float GetCrossProduct(in Vector2FP32 vector1, in Vector2FP32 vector2)
        {
            return vector1.x1 * vector2.x2 - vector1.x2 * vector2.x1;
        }

        public static float GetAngle(in Vector2FP32 vector1, in Vector2FP32 vector2, AngleUnit unit)
        {
            float squareModulus1 = vector1.GetSquareModulus();

            if (squareModulus1 <= UtilityFP32.SQUARE_EPSYLON)
            {
                return 0.0f;
            }

            float squareModulus2 = vector2.GetSquareModulus();

            if (squareModulus2 <= UtilityFP32.SQUARE_EPSYLON)
            {
                return 0.0f;
            }

            float cosine = Vector2FP32.GetScalarProduct(vector1, vector2) / MathF.Sqrt(squareModulus1 * squareModulus2);

            if (1.0f - UtilityFP32.EPSYLON <= cosine)
            {
                return 0.0f;
            }

            if (cosine <= -(1.0f - UtilityFP32.EPSYLON))
            {
                return AngleFP32.GetHalfCircle(unit);
            }
    
            return RadianFP32.ToUnits(MathF.Acos(cosine), unit);
        }
    
        public static float GetSquareDistance(in Vector2FP32 vector1, in Vector2FP32 vector2)
        {
            float dx1 = vector1.x1 - vector2.x1;
            float dx2 = vector1.x2 - vector2.x2;
        
            return dx1 * dx1 + dx2 * dx2;
        }
    
        public static float GetDistance(in Vector2FP32 vector1, in Vector2FP32 vector2)
        {
            return MathF.Sqrt(GetSquareDistance(vector1, vector2));
        }
    
        public static bool AreEqual(in Vector2FP32 vector1, in Vector2FP32 vector2)
        {
            float squareModulus1 = vector1.GetSquareModulus();
            float squareModulus2 = vector2.GetSquareModulus();
            float squareModulus3 = GetSquareDistance(vector1, vector2);

            // 2.0f means dimension amount
            if (squareModulus1 < UtilityFP32.EPSYLON_EFFECTIVENESS_LIMIT || squareModulus2 < UtilityFP32.EPSYLON_EFFECTIVENESS_LIMIT)
            {
                return squareModulus3 < (2.0f * UtilityFP32.SQUARE_EPSYLON);
            }

            if (squareModulus1 <= squareModulus2)
            {
                return squareModulus3 <= (2.0f * UtilityFP32.SQUARE_EPSYLON) * squareModulus2;
            }

            return squareModulus3 <= (2.0f * UtilityFP32.SQUARE_EPSYLON) * squareModulus1;
        }
    }
}