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Mode X in Turbo Pascal, Part 4: Tilemaps and Streaming
2026-02-22
A renderer becomes a game when it can show world-scale structure, not just local effects. That means tilemaps, camera movement, and disciplined data loading. In Mode X-era development, these systems were not optional polish. They were the only way to present rich scenes inside strict memory budgets.
This final Mode X article focuses on operational structure: how to build scenes that scroll smoothly, load predictably, and remain debuggable. ... continue
Mode X in Turbo Pascal, Part 3: Sprites and Palette Cycling
2026-02-22
Sprites are where a renderer starts to feel like a game engine. In Mode X, the challenge is not just drawing images quickly. The challenge is managing transparency, overlap order, and visual dynamism while staying within the strict memory and bandwidth constraints of VGA-era hardware.
If your primitives and clipping are not stable yet, go back to Part 2. Sprite bugs are hard enough without foundational uncertainty. ... continue
Mode X in Turbo Pascal, Part 2: Primitives and Clipping
2026-02-22
After the planar memory model clicks, the next trap is pretending linear drawing code can be “ported” to Mode X by changing one helper. That works for demos and fails for games. Robust Mode X rendering starts with primitives that are aware of planes, clipping, and page targets from day one.
If you missed the foundation, begin with Part 1: Planar Memory and Pages. This article assumes you already have working pixel output and page flipping. ... continue
Mode X in Turbo Pascal, Part 1: Planar Memory and Pages
2026-02-22
Mode 13h is the famous VGA “easy mode”: one byte per pixel, 320x200, 256 colors, linear memory. It is perfect for first experiments and still great for teaching rendering basics. But old DOS games that felt smoother than your own early experiments usually did not stop there. They switched to Mode X style layouts where planar memory, off-screen pages, and explicit register control gave better composition options and cleaner timing.
This first article in the series is about that mental model. Before writing sprite engines, tile systems, or palette tricks, you need to understand what the VGA memory controller is really doing. If the model is wrong, every optimization turns into folklore. ... continue
Mode 13h in Turbo Pascal: Graphics Programming Without Illusions
2026-02-22
Turbo Pascal graphics programming is one of the cleanest ways to learn what a frame actually is. In modern stacks, rendering often passes through layers that hide timing, memory layout, and write costs. In DOS Mode 13h, almost nothing is hidden. You get 320x200, 256 colors, and a linear framebuffer at segment $A000. Every pixel you draw is your responsibility.
Mode 13h became a favorite because it removed complexity that earlier VGA modes imposed. No planar bit operations, no complicated bank switching for this resolution, and no mystery about where bytes go. Pixel (x, y) maps to offset y * 320 + x. That directness made it ideal for demos, games, and educational experiments. It rewarded people who could reason about memory as geometry. ... continue