interpolate

gistfile1.glsl

vec3 interpolate(vec3 tri[3], vec3 vals[3], vec3 intersection)
{
    // Calculate barycentric coordinates
    float one_over_tri_area = 2.0f / length(cross(tri[1] - tri[0], tri[2] - tri[1]));
    float u = 0.5f * one_over_tri_area * length(cross(tri[1] - intersection, tri[2] - intersection));
    float v = 0.5f * one_over_tri_area * length(cross(tri[0] - intersection, tri[2] - intersection));
    float w = 0.5f * one_over_tri_area * length(cross(tri[0] - intersection, tri[1] - intersection));
    
    return vals[0] * u + vals[1] * v + vals[2] * w;
}