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OOPS, now I recall. DDA and Incremental error algorithms aren't synonymous. DDA is just the incrementing. the 'error'/decision branching part is indeed something else. I'm still looking for an "official term". |
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{{About|a graphics algorithm|the digital implementation of a differential analyzer|Digital differential analyzer}}
In [[computer graphics]], a '''[[digital differential analyzer]]''' ('''DDA''') is hardware or software used for [[interpolation]] of [[Variable (computer science)|variables]] over an [[Interval (mathematics)|interval]] between start and end point. DDAs are used for [[rasterization]] of lines, triangles and polygons. They can be extended to non linear functions, such as [[texture mapping#Perspective correctness|perspective correct texture mapping]], [[quadratic curves]], and
In its simplest implementation for linear cases such as [[line]]s, the DDA algorithm interpolates values in interval by computing for each x<sub>i</sub> the equations x<sub>i</sub> = x<sub>i−1</sub>+1/m, y<sub>i</sub> = y<sub>i−1</sub> + m, where Δx = x<sub>end</sub> − x<sub>start</sub> and Δy = y<sub>end</sub> − y<sub>start</sub> and m = Δy/Δx
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