Fix math for XY colors
parent
2a6a6e8697
commit
7d845f5ce8
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@ -30,7 +30,6 @@
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#include "zcl_include.h"
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#include "sampleLight.h"
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#include "sampleLightCtrl.h"
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#include <math.h>
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/**********************************************************************
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* LOCAL CONSTANTS
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@ -345,34 +344,72 @@ static float ENFORCE_BOUNDS_FLOAT(float lowerBound, float num, float upperBound)
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: num;
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}
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/*
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A horrible power function for floats
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*/
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static float fpow(float x, float y) {
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float result = 1;
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for(int i = 0; i < y; ++i)
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{
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result *= x;
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}
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return result;
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}
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float LINEAR_TO_SRGB_GAMMA_CORRECTION(const float part)
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{
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return part <= 0.0031308 ? 12.92 * part : 1.055 * pow(part, 1.0 / 2.4) - 0.055;
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return part <= 0.0031308f ? 12.92f * part : 1.055f * fpow(part, 1.0f / 2.4f) - 0.055f;
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}
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#define MAX(x,y) ((x) > (y) ? (x) : (y))
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#define MIN(x,y) ((x) < (y) ? (x) : (y))
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#define roundu8(a) (u8) (a+0.5)
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void hwLight_colorUpdate_XY2RGB(u16 xI, u16 yI, u8 level)
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{
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float x = xI / 65536.f;
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float y = yI / 65536.f;
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float x = xI / (float)ZCL_COLOR_ATTR_XY_MAX;
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float y = yI / (float)ZCL_COLOR_ATTR_XY_MAX;
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// This does not locate the closest point in the gamma spectrum of the lamps. possible #todo
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const float z = 1 - x - y;
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const float Y = level / ZCL_LEVEL_ATTR_MAX_LEVEL; // This is luminance, but used as brightness
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const float Y = level / (float)ZCL_LEVEL_ATTR_MAX_LEVEL; // This is luminance, but used as brightness
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const float X = ((Y) / y) * x;
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const float Z = ((Y) / y) * z;
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// D65 BT.709 conversion https://en.wikipedia.org/wiki/SRGB
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float r = X * 1.656492 - Y * 0.354851 - Z * 0.255038;
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float g = -X * 0.707196 + Y * 1.655397 + Z * 0.036152;
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float b = X * 0.051713 - Y * 0.121364 + Z * 1.011530;
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float r = X * 1.656492f - Y * 0.354851f - Z * 0.255038f;
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float g = -X * 0.707196f + Y * 1.655397f + Z * 0.036152f;
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float b = X * 0.051713f - Y * 0.121364f + Z * 1.011530f;
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// Normalize to maximum component being 1.0
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float maxComponent = MAX(MAX(r, g), b);
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if (maxComponent > 1.0) {
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r /= maxComponent;
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g /= maxComponent;
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b /= maxComponent;
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}
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// Apply LINEAR => SRGB Gamma correction
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r = LINEAR_TO_SRGB_GAMMA_CORRECTION(r);
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g = LINEAR_TO_SRGB_GAMMA_CORRECTION(g);
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b = LINEAR_TO_SRGB_GAMMA_CORRECTION(b);
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// Normalize again to avoid out of range
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maxComponent = MAX(MAX(r, g), b);
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if (maxComponent > 1.0) {
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r /= maxComponent;
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g /= maxComponent;
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b /= maxComponent;
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}
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// Enforce the lower and upper bounds
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r = ENFORCE_BOUNDS_FLOAT(0.0, r * 255, 255.0);
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g = ENFORCE_BOUNDS_FLOAT(0.0, g * 255, 255.0);
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b = ENFORCE_BOUNDS_FLOAT(0.0, b * 255, 255.0);
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r = ENFORCE_BOUNDS_FLOAT(0.0f, r * 255, 255.0f);
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g = ENFORCE_BOUNDS_FLOAT(0.0f, g * 255, 255.0f);
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b = ENFORCE_BOUNDS_FLOAT(0.0f, b * 255, 255.0f);
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hwLight_colorUpdate_RGB((u8)r, (u8)g, (u8)b);
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hwLight_colorUpdate_RGB(roundu8(r), roundu8(g), roundu8(b));
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}
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/*********************************************************************
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