Notes

Hub card for OpenGL (3.2 Core, Qt). Holds the core idea and the map to the atomic cards.

Core

• CPU builds data, then uploads it. GPU objects live in GPU memory; the CPU only holds a GLuint handle, a door number for the real object.
• Every glXXX() call asks the driver to act on some object N.
• OpenGL is a big state machine. glBindBuffer() / glUseProgram() select an object; later calls that read that slot use the selected object.
• Variable names like vao or bufferPosition are project examples, not OpenGL names.

1. Workflow

• OpenGL frame workflow: context → init once → every frame → cleanup, and what one draw call runs
• Qt OpenGL widget lifecycle: initializeGL / resizeGL / paintGL, update() vs paintGL()

2. Objects and data

• OpenGL handles and state machine: handles, context, binding, Gen → Bind → Operate
• OpenGL buffers and targets: targets, positions vs indices, upload by bytes
• VAO and VBO: VBO holds data, VAO saves the wiring; what moves to init
• NDC and aspect ratio correction: the [-1, 1] box, 2D homogeneous z = 1

3. API

• OpenGL API naming and call order: decode names, which call must come first, the three counts

4. Shaders

• GLSL in, out and uniform: per-vertex vs shared data, how each gets sent
• GLSL shader conventions: files, prefixes, built-ins, read-only in
• GLSL sin patterns: A·sin(F·x+P)+C, what to feed x, isolines, mix

5. Debugging

• OpenGL debugging: glGetError strategy, symptom → cause table

Not yet carded

Interleaved vertex layouts (stride/offset), textures and samplers, framebuffers, depth test and blending in GL.

Related

Graphics Pipeline Hub · Matrix composition order (SRT)