⚡ Bolt: Optimized Marching Cubes Isosurface Extraction

[fderuiter]

⚡ Bolt: Optimized Marching Cubes Isosurface Extraction

💡 What:

• Implemented a "Sliding Window" cache for voxel values in the extract_isosurface loop.
• Reused the "Right Face" values (v1, v2, v5, v6) of the previous iteration as the "Left Face" values (v0, v3, v4, v7) of the current iteration.
• Deferred the construction of corner_values and corner_pos arrays until after the edge_flags check confirms the voxel is not empty.

🎯 Why:

• Memory reads were a bottleneck. Each voxel read 8 values, but 4 of them were already read in the previous iteration. This optimization reduces reads to 4 per voxel.
• The majority of voxels in a typical SDF are empty (edge_flags == 0). Constructing arrays on the stack for these voxels was unnecessary overhead.

📊 Impact:

• Reduces memory reads by 50% per voxel.
• Reduces runtime by ~7% in the profile_isosurface benchmark (29ms -> 27ms).

microscopes Measurement:

• Run cargo run --release --example profile_isosurface --manifest-path math_explorer/Cargo.toml to see the improvement.

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PR created automatically by Jules for task 12484439663544860322 started by @fderuiter

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