DEVLOG 1

Test Project 1: "learn-sdl3"

This was my first test project, and mostly consisted of reading SDL3 and Vulkan API documentation, translating example C code into Odin (and learning Odin), and reading about GPU architecture and standard practices. The objective was initially to get a shaded triangle, but it evolved to rendering a textured quad.

Despite the simple looking result, a lot of configuration and setup went into making it happen, and it was a useful introduction to GPU programming!

• vulkan-tutorial.com
• SDL3 Documentation
• @TheSpydog's SDL GPU Examples
• Real-Time Rendering 4th Edition

Test Project 2: "test_3D_wireframe"

After the first test project, I needed a break from the GPU stuff--so I decided to brush off my linear algebra skills and make a 3D wireframe software renderer using Odin's built in `linalg` module and SDL3's `Renderer` API.

Put roughly, the system works by taking each models instance-space vertices (relative to the model's local origin) and transforms them to their world-space positions using the object's translation vector and transformation matrix. The worldspace positions are then transformed into camera-space positions, where the camera's origin is at z=-1 and its direction is along the +z axis; at which point the camera-space positions are projected on to the z=0 (XY) plane by drawing a line from the camera origin at (0, 0, -1) to each position in camera-space and solving for that line's intersection with the z=0 (XY) plane. Finally, I can normalize the projected points based on the size of the plane, and then multiply by the screen dimensions to determine where the points should be drawn on the screen. From there it's just a matter of drawing the connecting lines to render the wireframes.

TLDR:
It's a mouthful, but it's not too hard to wrap your head around conceptually if you imagine coordinate changes as simple shifts in perspective. The pipeline then becomes:

• > Points relative to the model's center
• > Points relative to the world's center
• > Points relative to the camera's center and orientation
• > Points relative to the projection plane's center
• > Points relative to the screen's corner

• SDL3 Documentation

Test Project 3: "test_lighting"

The purpose of this project was twofold! 1: I wanted to mess around with a raycast-driven lighting algorithm I'd been thinking about, and 2: I wanted to make a tesselation alogrithm capable of handling concave polygons for funsies. The project offered plenty of insight into how much I'll be able to get out of the CPU during realtime lighting calculations, and reinforced the importance of leveraging the GPU for tesselation and rasterization.

Lighting is an important aspect in Nyctophobia, so it's important that I get it right without sacrificing accuracy or performance.

• SDL3 Documentation