Last time, I talked about racing the beam, a type of graphics used when memory was scarce. Now it’s time to step into the future with more memory and talk about what modern 2D games still do to this day: rasterization.
Just in time Memory
Continuing the trend set by racing the beam, rasterized graphics are also on a grid, just a much tinier one. Though not unique to rasterized, the “frame buffer” is the logical conclusion of bitmap mode fidelity: enough memory is allocated so that every pixel can have its own color. What’s different about a frame buffer is that everything is drawn before it is shown and, crucially, this doesn’t have to happen in the same order as the pixels are displayed. Rasterization draws entire shapes — triangles, lines and rectangles — into the frame buffer and the screen is typically updated all at once.
Crude Circles
You may have noticed I didn’t mention circles earlier. That’s because we don’t actually draw circles, we approximate them. It’s a simple thing, really: Would you rather draw 50 triangles, or compute 10000 distance calculations? Well, if you said triangles, the computers agree with you.
This diagram shows an exaggerated representation of how a circle can be approximated using triangles. It’s quite obvious here where the triangles are, but the more triangles you add, the closer you can get to a perfect circle. More complex shapes, like text, polygons and abstract shapes can also be made with triangles.
The plotting predicament
But ..
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