Prerender the static level #2

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Nigel · 2026-01-19T22:26:08Z

Nigel commented

2026-01-19 22:26:08 +00:00

we can pre render the static stuff in the level and draw it as one big texture behond the dynamic sprites.

AI:

🧱 Option: Pre-render the Tilemap into a Single Texture

Instead of rendering each tile individually every frame, you can:

Render the entire tilemap once into a larger texture (a framebuffer-backed texture).
Then, during gameplay, draw a single quad textured with that pre-rendered level.

✅ Benefits

Performance boost: One draw call instead of hundreds or thousands.
Simpler render loop: No need to loop over tilemap every frame.
Great for static backgrounds: Perfect for Pac-Man’s maze, which rarely changes.

🧰 How to Do It

Create a framebuffer + texture to render into:

`c
GLuint fbo, levelTexture;
glGenFramebuffers(1, &fbo);
glBindFramebuffer(GL_FRAMEBUFFER, fbo);

// Create texture to render into
glGenTextures(1, &levelTexture);
glBindTexture(GLTEXTURE2D, levelTexture);
glTexImage2D(GLTEXTURE2D, 0, GLRGBA, levelWidth, levelHeight, 0, GLRGBA, GLUNSIGNEDBYTE, NULL);
glTexParameteri(GLTEXTURE2D, GLTEXTUREMINFILTER, GLNEAREST);
glTexParameteri(GLTEXTURE2D, GLTEXTUREMAGFILTER, GLNEAREST);
glFramebufferTexture2D(GLFRAMEBUFFER, GLCOLORATTACHMENT0, GLTEXTURE_2D, levelTexture, 0);
`

Render the tilemap to the framebuffer:
- Bind the framebuffer.
- Loop over your tilemap.
- For each tile, draw a quad with the correct UV offset from the atlas.
- Unbind the framebuffer when done.
In your main render loop:
- Bind the default framebuffer.
- Draw a single fullscreen or camera-aligned quad using levelTexture.

⚠️ Considerations

If your level changes (e.g. pellets disappear), you’ll need to re-render the level texture or layer dynamic elements (like pellets, Pac-Man, ghosts) on top.
You’ll need to manage camera transforms if your level is larger than the screen.
This approach works best when the background is static and only foreground elements (like characters) move.

🧠 Hybrid Strategy

For a Pac-Man clone, a hybrid approach is ideal:

Static maze walls → pre-rendered to a level texture.
Dynamic elements (Pac-Man, ghosts, pellets) → rendered as instanced quads on top.

This gives you the best of both worlds: performance and flexibility.

Would you like help setting up the framebuffer rendering code or designing the atlas layout for this approach?

we can pre render the static stuff in the level and draw it as one big texture behond the dynamic sprites. AI: --- 🧱 Option: Pre-render the Tilemap into a Single Texture Instead of rendering each tile individually every frame, you can: 1. Render the entire tilemap once into a larger texture (a framebuffer-backed texture). 2. Then, during gameplay, draw a single quad textured with that pre-rendered level. --- ✅ Benefits - Performance boost: One draw call instead of hundreds or thousands. - Simpler render loop: No need to loop over tilemap every frame. - Great for static backgrounds: Perfect for Pac-Man’s maze, which rarely changes. --- 🧰 How to Do It 1. Create a framebuffer + texture to render into: `c GLuint fbo, levelTexture; glGenFramebuffers(1, &fbo); glBindFramebuffer(GL_FRAMEBUFFER, fbo); // Create texture to render into glGenTextures(1, &levelTexture); glBindTexture(GLTEXTURE2D, levelTexture); glTexImage2D(GLTEXTURE2D, 0, GLRGBA, levelWidth, levelHeight, 0, GLRGBA, GLUNSIGNEDBYTE, NULL); glTexParameteri(GLTEXTURE2D, GLTEXTUREMINFILTER, GLNEAREST); glTexParameteri(GLTEXTURE2D, GLTEXTUREMAGFILTER, GLNEAREST); glFramebufferTexture2D(GLFRAMEBUFFER, GLCOLORATTACHMENT0, GLTEXTURE_2D, levelTexture, 0); ` 2. Render the tilemap to the framebuffer: - Bind the framebuffer. - Loop over your tilemap. - For each tile, draw a quad with the correct UV offset from the atlas. - Unbind the framebuffer when done. 3. In your main render loop: - Bind the default framebuffer. - Draw a single fullscreen or camera-aligned quad using levelTexture. --- ⚠️ Considerations - If your level changes (e.g. pellets disappear), you’ll need to re-render the level texture or layer dynamic elements (like pellets, Pac-Man, ghosts) on top. - You’ll need to manage camera transforms if your level is larger than the screen. - This approach works best when the background is static and only foreground elements (like characters) move. --- 🧠 Hybrid Strategy For a Pac-Man clone, a hybrid approach is ideal: - Static maze walls → pre-rendered to a level texture. - Dynamic elements (Pac-Man, ghosts, pellets) → rendered as instanced quads on top. This gives you the best of both worlds: performance and flexibility. --- Would you like help setting up the framebuffer rendering code or designing the atlas layout for this approach?

Nigel added the enhancement label 2026-01-19 22:26:08 +00:00

Nigel self-assigned this 2026-01-19 22:26:08 +00:00

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Reference: Nigel/Pacman-Clone#2