A sparse point gradient interpolator using a barycentric coordinate system for interpolation
Based on three (and only three) vertices, with each vertex specified with a certain color, a linear triangle of color is calculated.
Typically the three vertices are mapped to the vertices of a given 3-point polygon that should be filled. However, this is not required as the colours continue as before outside this triangle.
Figure 1: Example polygon filled with a TBarycentricGradientPolygonFiller