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palette effect overflow fix #4435

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Merged
merged 1 commit into from
Jan 9, 2025
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palette effect overflow fix #4435

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2 changes: 1 addition & 1 deletion wled00/FX.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2032,7 +2032,7 @@ uint16_t mode_palette() {
const mathType sourceX = xtSinTheta + ytCosTheta + centerX;
// The computation was scaled just right so that the result should always be in range [0, maxXOut], but enforce this anyway
// to account for imprecision. Then scale it so that the range is [0, 255], which we can use with the palette.
int colorIndex = (std::min(std::max(sourceX, mathType(0)), maxXOut * sInt16Scale) * 255) / (sInt16Scale * maxXOut);
int colorIndex = (std::min(std::max(sourceX, mathType(0)), maxXOut * sInt16Scale) * wideMathType(255)) / (sInt16Scale * maxXOut);
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@softhack007 softhack007 Dec 28, 2024 •
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What does wideMathType() do?

Essentially this PR changes "255" to "wideMathType(255)", I'm wondering is this the same as writing "255.0f" or maybe "255L" ?

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@blazoncek blazoncek Dec 28, 2024

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255ULL for ESP8266 and 255.0f otherwise

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@softhack007 softhack007 Dec 28, 2024

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Looks like someone tried to avoid fixed point math?

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@DedeHai DedeHai Dec 29, 2024

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the way it is implemented is quite an elegant way to support float AND fixed point math.

// inputSize determines by how much we want to scale the palette:
// values < 128 display a fraction of a palette,
// values > 128 display multiple palettes.
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