Scale & conventions

Keep the whole course consistent so assets and code plug together.

Units & axes

Convention	Choice
World up	+Y
Typical forward	−Z or +Z — match Tiny3D examples; document in first 3D lesson and stick to it
Gameplay scale	1.0 ≈ 1 meter for human-scale props; player ~1.5–2.0 tall
Course t3dm scales	Raw verts are large integers; ROMs apply e.g. island ~0.032, snake ~0.02, starshard ~0.02 so the world fits a ~12-unit island and a short follow cam
Snake model yaw	Course snake mesh faces −Z; pass -yaw into t3d_mat4fp_from_srt_euler so stick left/right match the model
Angles in course math notes	Degrees in prose; radians in C when APIs require

Display / VI

Topic	Course convention
Resolution	320×240, DEPTH_16_BPP
VI filters	FILTERS_RESAMPLE only — avoid FILTERS_RESAMPLE_ANTIALIAS (can leave a 1px green/cyan flicker on the top edge)
Clear color	Opaque (alpha 0xFF) with Tiny3D t3d_screen_clear_color

Tiny3D matrix stack

After t3d_viewport_attach, the stack holds the camera. Per object:

t3d_matrix_push(modelMat);
t3d_model_draw(...) / vert_load(...);
t3d_matrix_pop(1);

Avoid t3d_matrix_set in that slot unless you fully understand the stack — a common failure mode is clear color + HUD text with no 3D.

Buffered skeletons: t3d_skeleton_use(&skel) before t3d_model_draw_skinned.

Player / camera (Module 4–5 + capstone)

Topic	Course convention
camYaw	Horizontal camera angle only (C-left/right). Not player facing
Move basis	Rotate stick by the lagged camera direction (eye→player on XZ), not by player yaw. Fallback to camYaw if eye is on top of the player
Player yaw	Model facing only — updates toward move direction; never drives the camera basis
Soft-follow	Do not lerp camYaw toward player yaw (they sit ~π apart → continuous spin)
Soft wall	Axis-aligned box clamp (e.g. ±5.5), not a radial cylinder (radial skates the rim)
Stick-up	Into the scene (away from camera), along look on XZ

Audio (Module 5 + capstone)

Topic	Course convention
Opus wav64	Pipeline uses --wav-compress 3 → 48 kHz samples
Init	audio_init(48000, …) — lower rates assert on play (frequency 48000 exceeds configured limit)
Per frame	mixer_try_play() after (or with) the present

Textures

• Prefer 32×32 or 64×64 for props; avoid huge maps
• Power-of-two dimensions
• Vertex color for large-scale tinting instead of unique giant textures

Vertex color (Fast64 / Tiny3D)

• Color attribute / layer names: Col and Alpha (Fast64 convention)
• Course default material path: texture modulated by vertex color for terrain
• Always ship a pre-exported glTF that already has correct layers

Animation

• Clips required for capstone: idle, walk (course names: Snake_Idle / Snake_Walk)
• Looping, on-the-spot cycles
• Low bone count; respect Tiny3D 1-bone-per-vertex weighting
• Course ships a reference armature under assets-src/blender/

Code style (light)

• C11 as supported by libdragon’s GCC
• Prefer clear names over clever macros
• Match libdragon / Tiny3D example style so Discord help is easy