palette effect overflow fix #4435
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Note: this does replace some more 32 bit multiplications with slightly more expensive 64 bit multiplications. |
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Tested and works. |
softhack007
reviewed
Dec 28, 2024
| @@ -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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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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255ULL for ESP8266 and 255.0f otherwise
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Looks like someone tried to avoid fixed point math?
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the way it is implemented is quite an elegant way to support float AND fixed point math.
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I belive this fixes #4425