2D Array Interpolation

Question

i am currently working on a 3D game in c#. I have a 2 dimensional array called data where i get a z value for my x and y

Answer 1

Maybe Bilinear Interpolation can be used in your scenario:

float fractionX = ... //the fraction part of the x coordinate
float integerX = ... //the integer part of the x coordinate
float fractionY, integerY = ...
interpolatedValue = (1 - fractionX) * 
                        ((1 - fractionY) * data[integerX, integerY] + 
                         fractionY * data[integerX, integerY + 1]) + 
                    fractionX * 
                        ((1 - fractionY) * data[integerX + 1, integerY] + 
                        fractionY * data[integerX + 1, integerY + 1]);

Interpolating between 0, 4, 1 and 3 yields the following result:

If you have triangulated the height map, Barycentric Interpolation might be more appropriate:

//Assuming the following triangle alignment:
//  1 +--+--+--+
//    | /| /| /|
//    |/ |/ |/ |
//  0 +--+--+--+

if (fractionX < fractionY) //the upper triangle
{
    interpolatedValue = (1 - fractionY) * data[integerX, integerY] +
                        fractionX * data[integerX + 1, integerY + 1] +
                        (fractionY - fractionX) * data[integerX, integerY + 1];
}
else //the lower triangle
{
    interpolatedValue = (1 - fractionX) * data[integerX, integerY] +
                        fractionY * data[integerX + 1, integerY + 1] +
                        (fractionX - fractionY) * data[integerX + 1, integerY];
}

Interpolating between 0, 4, 1 and 3 yields the following result: