Pinwheel Rework

[Brandon502]

Previous discussions here: #4185
Pinwheel algorithm optimized. Math and memory optimizations by @DedeHai

May still have a few quirks in untested matrix sizes / effects.

Summary by CodeRabbit

• New Features
  • The LED pinwheel effect now delivers smoother, more precise animations for a consistently improved visual experience.
• Refactor
  • Redesigned the calculation logic for effect positioning and step sizing, ensuring a more reliable and artifact-free display.

[coderabbitai]

Walkthrough

The pull request refactors the pinwheel effect logic within the WS2812FX implementation. It removes several constants previously used for effect dimensions and angles, updates the fixed scale constant from 512 to 16384, and introduces a new helper function to compute pinwheel parameters using Bresenham’s algorithm. Additionally, the pixel color setting method is updated to incorporate the new logic.

Changes

File

Change Summary

wled00/FX_fcn.cpp

- Removed constants: Pinwheel_Steps_Small, Pinwheel_Size_Small, Pinwheel_Steps_Medium, Pinwheel_Size_Medium, Pinwheel_Steps_Big, Pinwheel_Size_Big, Pinwheel_Steps_XL, and associated Int_to_Rad* constants. - Updated constant Fixed_Scale from 512 to 16384. - Added new function setPinwheelParameters for calculating starting coordinates and angular steps using Bresenham's algorithm. - Modified setPixelColor to integrate the new pinwheel logic.

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Actionable comments posted: 0

🧹 Nitpick comments (2)

wled00/FX_fcn.cpp (2)

689-702: Validate scale-safety for angles and expansions.

The calculations in setPinwheelParameters() rely on (i + k) * baseAngle. If i becomes unexpectedly large, there could be potential overflow when multiplied by baseAngle. Consider clamping or validating the range of i to ensure it cannot exceed the pinwheel length.

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836-930: Potential stack usage concern and index checks.

1. uint16_t lineCoords[2][maxLineLength]; since maxLineLength is max(vW, vH) + 2, large 2D matrices could pressure stack memory. A comment or safeguard to prevent overly large arrays might be warranted.
2. At lines 864-866, closestEdgeIdx = min(closestEdgeIdx, idx-2); relies on an incremented idx to be at least 2 after the first iteration. This logic is sound given the immediate increment, but consider an extra defensive check if future changes alter that loop’s indexing mechanism.
3. At line 900, there is a note “//!! should be long line idx!” clarifying which index to read from. Ensure that the commented hint matches intended usage (using longLineIdx consistently) or consider a minor refactor for clarity to avoid confusion.

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📥 Commits

Reviewing files that changed from the base of the PR and between a0c55c6 and e7e0eb0.

📒 Files selected for processing (1)

• wled00/FX_fcn.cpp (3 hunks)

⏰ Context from checks skipped due to timeout of 90000ms (6)

• GitHub Check: wled_build / Build Enviornments (esp32s3_4M_qspi)
• GitHub Check: wled_build / Build Enviornments (esp32s3dev_8MB_opi)
• GitHub Check: wled_build / Build Enviornments (esp32s3dev_16MB_opi)
• GitHub Check: wled_build / Build Enviornments (lolin_s2_mini)
• GitHub Check: wled_build / Build Enviornments (esp32_eth)
• GitHub Check: wled_build / Build Enviornments (esp8266_2m)

🔇 Additional comments (3)

wled00/FX_fcn.cpp (3)

683-684: Good introduction of a higher fixed-point scale.

The larger Fixed_Scale value (16384) increases precision in trigonometric calculations for the pinwheel effect. This should reduce rounding artifacts for 2D transformations.

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685-688: Ensure consistent usage of the pinwheel step size.

The function getPinwheelLength() always returns a multiple of 8. While this helps avoid over-drawing, ensure all code paths using pinwheel rays respect this multiple-of-8 strategy and do not silently assume a different step geometry.

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1064-1077: Double-check edge tracing in getPixelColor.

Using setPinwheelParameters(i, vW, vH, x, y, cosVal, sinVal, true) to rotate half a ray width is a clever approach. However, the while loop at lines 1069-1071 stops once any edge is reached. Confirm that cases where vW or vH is 1 or very small matrices still produce an expected result, as the logic could exit immediately with minimal coverage.