formatting, improve dda

COMPSCI-3GC3/3gc3-midterm.tex

@@ -420,7 +420,7 @@ \section{Camera / Viewing Transformations}
 Step 1 (left matrix): Translates camera position $e$ to origin $e$. Things originally at $e$ are now at $\vec{0}$.\\
 Step 2 (right matrix): Rotates, maps basis vectors: $u \mapsto (1,0,0), v \mapsto (0,1,0), w \mapsto (0,0,1)$
 
-\textbf{3x3 Camera Matrix}
+\textbf{3\(\times\)3 Camera Matrix}
 \(
 M_{cam}
 = \begin{bmatrix}
@@ -530,7 +530,10 @@ \section{Rasterization}
 Implicit line function: $f(x,y): Ax + By + C = 0$. Checking sign of $f(x_P, y_P)$ can determine point position relative to line.\\
 
 \textbf{Naive Implementation:} Use the function $y=mx+c$ and iterate $x$ from $x_0$ to $x_1$. No vertical lines!\\
-\textbf{Digital Difference Analyser DDA:} Similar, but move in the axis that is shallower.
+\textbf{Digital Difference Analyser DDA:}
+Precomputes step size for both Y and X from line function.
+Marches in direction based on which value changes slower:
+if y changes slower march in the x direction and vice versa.
 
 % \includegraphics[width=\linewidth]{rasterize-dda.png} 
 \begin{lstlisting}
@@ -601,7 +604,7 @@ \section{Rasterization}
 \textbf{Bresenham Algorithm:}
 
 % \includegraphics[width=\linewidth]{rasterize-bresen.png}\\
-\begin{lstlisting} 
+\begin{lstlisting}
 drawBresenham(x0, y0, x1, y1):
     deltaX = x1-x0
     deltaY = y1-y0