Sliced Pokeball + Wobbling Ditto (PBR + GLSL)

The Problem

Slice a complex 3D model in real time without breaking lighting or shadow behavior — apply the effect only to specific meshes, keep the interior readable, and add an organic wobble animation to Ditto without deforming the Pokeball shell.

Solution

• Radial slicing using fragment-space angle math: `atan(y, x)` with `uSliceStart` offset and `mod(angle, 2*PI)` wrapping to prevent slicing glitches across negative angles.
• Selective slicing by targeting only specific mesh names (Pokeball parts) during GLTF traversal, leaving other meshes unaffected.
• Stylized interior cut by rendering backfaces with a controlled slice color using `gl_FrontFacing` and DoubleSide.
• Preserved PBR lighting while adding custom behavior by injecting shader logic into built-in materials using CustomShaderMaterial instead of replacing the entire shading pipeline.
• Correct slice shadows by implementing a matching custom depth material (MeshDepthMaterial + RGBADepthPacking) so shadow maps reflect the same discard logic.
• Added an organic wobble deformation to Ditto only by injecting vertex displacement into MeshPhysicalMaterial while keeping reflections, environment lighting, and material response intact.
• Kept the project portable for deployment by loading GLB/Draco using `import.meta.env.BASE_URL` so assets resolve correctly on GitHub Pages.

Results

• Clean sliced-model reveal with a readable interior cut and correct lighting response.
• Consistent shadows that match the slicing effect, including depth-map correctness.
• Ditto-only wobble creates a strong visual focal point without destabilizing the Pokeball presentation.

Next

• Animate slice start/arc for a clean reveal sequence (with easing).
• Add a performance toggle for shadows + devicePixelRatio clamping.
• Add subtle interior shading variation so the cut surface reads more “3D” without heavy geometry rebuild.