tur-sdf-raylib

SDF-based solid modeling with raylib rendering and colored mesh export. Build signed-distance-field scenes, extract meshes via marching cubes, export to STL/OBJ/glTF, and preview live in a raylib window.

Overview

tur-sdf-raylib is a Tier 3 spice (cmake-dep -- pulls in raylib 5.5 via tur fetch). It depends on tur-math for vector math. The spice exposes a constructive-solid-geometry pipeline:

1. SDF construction -- primitive shapes (sphere, box, cylinder, plane, torus, capsule) composed with boolean ops (union, intersection, difference, smooth union/intersection) and transforms (translate, offset, shell, repeat).
2. Evaluation -- sdf-eval samples the distance field at a point; sdf-normal-* computes the surface normal.
3. Mesh extraction -- mc-extract runs marching cubes on a bounded box; mc-extract-colored / dc-extract-colored carry per-vertex colors and object IDs.
4. Export -- export-stl, export-obj, export-glb write the extracted mesh to disk.
5. Preview -- sdf-preview-window opens a raylib window with orbit controls; csdf-preview-window does the same for colored scenes.
6. GLSL codegen -- csdf->glsl compiles a colored SDF tree into a GLSL fragment shader string for GPU-side rendering.

Install

:spices {
  "sdf-raylib" {:url    "https://github.com/turmeric-lang/turmeric-spices"
                :ref    "sdf-raylib-v0.1.0"
                :subdir "spices/sdf-raylib"}
  "math" {:url    "https://github.com/turmeric-lang/turmeric-spices"
          :ref    "math-v0.1.0"
          :subdir "spices/math"}
}

Quick start

(import sdf/primitives    :refer [sdf-sphere sdf-box])
(import sdf/boolean       :refer [sdf-difference sdf-union])
(import sdf/transforms    :refer [sdf-translate])
(import sdf/eval          :refer [sdf-eval])
(import sdf/expr          :refer [sdf-free])
(import mesh/marching-cubes :refer [mc-extract mesh-free])
(import export/stl        :refer [export-stl])
(import raylib/integration :refer [sdf-preview-window])

(let [body (sdf-sphere 0.0 0.0 0.0 1.5)
      hole (sdf-box -0.5 -0.5 -2.0 0.5 0.5 2.0)
      core (sdf-difference body hole)
      sat  (sdf-translate (sdf-sphere 0.0 0.0 0.0 0.45) 2.4 0.0 0.0)
      scene (sdf-union core sat)]
  (println "SDF at origin:" (sdf-eval scene 0.0 0.0 0.0))
  (let [mesh (mc-extract scene 32 -3.0 -3.0 -3.0 3.0 3.0 3.0)]
    (export-stl mesh "hello-sphere.stl")
    (mesh-free mesh))
  (sdf-preview-window scene 800 600 4 "Hello Sphere")
  (sdf-free scene))

#lang sweet-exp
import sdf/primitives    :refer [sdf-sphere sdf-box]
import sdf/boolean       :refer [sdf-difference sdf-union]
import sdf/transforms    :refer [sdf-translate]
import sdf/eval          :refer [sdf-eval]
import sdf/expr          :refer [sdf-free]
import mesh/marching-cubes :refer [mc-extract mesh-free]
import export/stl        :refer [export-stl]
import raylib/integration :refer [sdf-preview-window]

let [body sdf-sphere(0.0 0.0 0.0 1.5)
     hole sdf-box(-0.5 -0.5 -2.0 0.5 0.5 2.0)
     core sdf-difference(body hole)
     sat  sdf-translate(sdf-sphere(0.0 0.0 0.0 0.45) 2.4 0.0 0.0)
     scene sdf-union(core sat)]
  println $ "SDF at origin:" sdf-eval(scene 0.0 0.0 0.0)
  let [mesh mc-extract(scene 32 -3.0 -3.0 -3.0 3.0 3.0 3.0)]
    export-stl(mesh "hello-sphere.stl")
    mesh-free(mesh)
  sdf-preview-window(scene 800 600 4 "Hello Sphere")
  sdf-free(scene)

Modules

Resource management

SDF trees are heap-allocated handles. Call sdf-free (or csdf-free for colored scenes) when the tree is no longer needed. Meshes from mc-extract / mc-extract-colored must be freed with mesh-free / cmesh-free. Welded meshes use imesh-free.

See also

• API reference
• Source: https://github.com/turmeric-lang/turmeric-spices/tree/main/spices/sdf-raylib