Digital differential analyzer (graphics algorithm)

In <a href="/facts/Computer_graphics/lapBE8wv">computer graphics</a>, a digital differential analyzer (DDA) is hardware or software used for <a href="/facts/Interpolation/8PyetX4f">interpolation</a> of <a href="/facts/Variable_(computer_science)/VoCKtwml">variables</a> over an <a href="/facts/Interval_(mathematics)/e9se3vTe">interval</a> between start and end point. DDAs are used for <a href="/facts/Rasterization/QXfz5t7E">rasterization</a> of lines, triangles and polygons. They can be extended to non linear functions, such as <a href="/facts/Texture_mapping/9gDTsuXN">perspective correct texture mapping</a>, quadratic curves, and traversing <a href="/facts/Voxels/xo077lPE">voxels</a>.
In its simplest implementation for linear cases such as <a href="/facts/Line_(geometry)/gJqsr4Gj">lines</a>, the DDA algorithm interpolates values in interval by computing for each xi the equations xi = xi−1 + 1, yi = yi−1 + m, where m is the <a href="/facts/Slope/a2L3k0j5">slope</a> of the line. This slope can be expressed in DDA as follows:

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    {\displaystyle m={\frac {y_{\rm {end}}-y_{\rm {start}}}{x_{\rm {end}}-x_{\rm {start}}}}}

In fact any two consecutive points lying on this line segment should satisfy the equation.

Digital differential analyzer (graphics algorithm) open-in-new

Digital differential analyzer (graphics algorithm)