scalarramplut.h File Reference

#include <QtGlobal>
#include <algorithm>
#include <cmath>

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Classes
struct	OpenSWMM::Render::ScalarRampLut

Namespaces
namespace	OpenSWMM
namespace	OpenSWMM::Render

Detailed Description

Author

Caleb Buahin caleb.nosp@m..bua.nosp@m.hin@g.nosp@m.mail.nosp@m..com

Date

2026

License\n GPL-3.0-or-later

QSG-2D-1M Phase 8 — pure scalar→ramp-index math for GPU color mapping.

The shader fill path uploads raw per-vertex scalars plus a small 1-D ramp texture (LUT); the GPU normalizes the scalar and samples the LUT. This header holds the pure normalization/clamp contract shared by the CPU LUT baker and the shader (which mirrors it in GLSL):

 t = clamp((value - vMin) / (vMax - vMin), 0, 1)

Degenerate ranges (vMax <= vMin) and non-finite values clamp to 0 so a bad frame can never index out of the LUT. Unit-tested headlessly in tests/unit/test_scalarramplut.cpp; the texture itself is verified visually (shader output is not meaningfully unit-testable).