SDL

Drawing a point on the screen is the first function that one may search in graphics programming. Plotting a pixel is the basic unit of all other graphical objects we see in everyday computing. In this article, we will take a look at how it is done using SDL's surface buffer.

Assuming you've already configured your SDL "includes" and 'libraries", we start the program by initializing the SDL libraries. Initializing SDL Video is the first step before using any of its graphic functions. You do this by:

With trigonometry functions such as sine and cosine, it is very easy to compute for the value of x and y for any given radius and teta.

We've all learned this from highschool and college class and it will not be tacked in this article. However, drawing a circle using these functions requires the usage of floating-point numbers which is slow, not to mention the typecasting from floating-point to integers as plotting a pixel requires such datatype.

The line equation represented by y = mx + b, is one of the most basic formulas in plotting a line. Where m represents the slope, x represents the value in horizontal coordinate and b represents the offset from y.

Suppose we have a line segment (x₁, y₁) to (x₂, y₂), the slope can be easily computed as (y₂ - y₁) / (x₂ - x₁) or to understand it better, we can read it as an increment in y for every step in x.