Interpolates between two values using a cubic equation. - Java java.lang

Java examples for java.lang:Math Curve

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Description

Interpolates between two values using a cubic equation.

Demo Code



public class Main{
    /**/*from   www . j  av  a  2 s .co  m*/
     * Interpolates between two values using a cubic equation.
     * 
     * @param value1
     *        Source value.
     * @param value2
     *        Source value.
     * @param amount
     *        Weighting value.
     * @return The interpolated value.
     */
    public static float smoothStep(float value1, float value2, float amount) {
        // It is expected that 0 < amount < 1
        // If amount < 0, return value1
        // If amount > 1, return value2
        float result = MathHelper.clamp(amount, 0f, 1f);
        result = MathHelper.hermite(value1, 0f, value2, 0f, result);

        return result;
    }
    /**
     * Restricts a value to be within a specified range.
     * 
     * @param value
     *        The value to clamp.
     * @param min
     *        The minimum value. If {@code value} is less than {@code min}, {@code min} will be
     *        returned.
     * @param max
     *        The maximum value. If {@code value} is greater than {@code max}, {@code max} will be
     *        returned.
     * @return The clamped value.
     */
    public static float clamp(float value, float min, float max) {
        // First we check to see if we're greater than the max
        value = (value > max) ? max : value;

        // Then we check to see if we're less than the min.
        value = (value < min) ? min : value;

        // There's no check to see if min > max.
        return value;
    }
    /**
     * Restricts a value to be within a specified range.
     * 
     * @param value
     *        The value to clamp.
     * @param min
     *        The minimum value. If {@code value} is less than {@code min}, {@code min} will be
     *        returned.
     * @param max
     *        The maximum value. If {@code value} is greater than {@code max}, {@code max} will be
     *        returned.
     * @return The clamped value.
     */
    public static int clamp(int value, int min, int max) {
        value = (value > max) ? max : value;
        value = (value < min) ? min : value;
        return value;
    }
    /**
     * Performs a Hermite spline interpolation.
     * 
     * @param value1
     *        Source position.
     * @param tangent1
     *        Source tangent.
     * @param value2
     *        Source position.
     * @param tangent2
     *        Source tangent.
     * @param amount
     *        Weighting factor.
     * @return The result of the Hermite spline interpolation.
     */
    public static float hermite(float value1, float tangent1, float value2,
            float tangent2, float amount) {
        // All transformed to double not to lose precission
        // Otherwise, for high numbers of param:amount the result is NaN instead
        // of Infinity
        double v1 = value1, v2 = value2, t1 = tangent1, t2 = tangent2, s = amount, result;
        double sCubed = s * s * s;
        double sSquared = s * s;

        if (amount == 0f)
            result = value1;
        else if (amount == 1f)
            result = value2;
        else
            result = (2 * v1 - 2 * v2 + t2 + t1) * sCubed
                    + (3 * v2 - 3 * v1 - 2 * t1 - t2) * sSquared + t1 * s
                    + v1;
        return (float) result;
    }
}

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