11-rasterization.md

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Rasterization

Rasterization is the process of converting points to discrete pixels.

Digital Differential Analyzer (DDA) Algorithm

• The simplest scan-conversion algorithm for line segments
• ∆y = m∆x → ∆y = m

for (ix=x1; ix <= x2; ix++) {
	y += m;
	write_pixel(x, round(y), line_color);
}

Bresenham's Line Algorithm

plotLine(x0,y0, x1,y1)
  dx = x1 - x0
  dy = y1 - y0
  D = 2*dy - dx
  y = y0

  for x from x0 to x1
    plot(x,y)
    if D > 0
       y = y + 1
       D = D - 2*dx
    end if
    D = D + 2*dy