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Fix transfer functions where toGamma and toLinear are swapped.

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Change-Id: I2f7ef84d227009181dad1c17883741bd98bf92b6
This commit is contained in:
Maryla 2023-10-12 16:57:32 +02:00
parent e7b78d4375
commit deadc339d5
1 changed files with 17 additions and 17 deletions
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34
sharpyuv/sharpyuv_gamma.c
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@ -156,19 +156,19 @@ static float FromLinear709(float linear) {
} }
static float ToLinear470M(float gamma) { static float ToLinear470M(float gamma) {
return Powf(CLAMP(gamma, 0.f, 1.f), 1.f / 2.2f); return Powf(CLAMP(gamma, 0.f, 1.f), 2.2f);
} }
static float FromLinear470M(float linear) { static float FromLinear470M(float linear) {
return Powf(CLAMP(linear, 0.f, 1.f), 2.2f); return Powf(CLAMP(linear, 0.f, 1.f), 1.f / 2.2f);
} }
static float ToLinear470Bg(float gamma) { static float ToLinear470Bg(float gamma) {
return Powf(CLAMP(gamma, 0.f, 1.f), 1.f / 2.8f); return Powf(CLAMP(gamma, 0.f, 1.f), 2.8f);
} }
static float FromLinear470Bg(float linear) { static float FromLinear470Bg(float linear) {
return Powf(CLAMP(linear, 0.f, 1.f), 2.8f); return Powf(CLAMP(linear, 0.f, 1.f), 1.f / 2.8f);
} }
static float ToLinearSmpte240(float gamma) { static float ToLinearSmpte240(float gamma) {
@ -194,26 +194,26 @@ static float FromLinearSmpte240(float linear) {
} }
static float ToLinearLog100(float gamma) { static float ToLinearLog100(float gamma) {
return (gamma < 0.01f) ? 0.0f : 1.0f + Log10f(MIN(gamma, 1.f)) / 2.0f; // The function is non-bijective so choose the middle of [0, 0.01].
const float mid_interval = 0.01f / 2.f;
return (gamma <= 0.0f) ? mid_interval
: Powf(10.0f, 2.f * (MIN(gamma, 1.f) - 1.0f));
} }
static float FromLinearLog100(float linear) { static float FromLinearLog100(float linear) {
// The function is non-bijective so choose the middle of [0, 0.01]. return (linear < 0.01f) ? 0.0f : 1.0f + Log10f(MIN(linear, 1.f)) / 2.0f;
const float mid_interval = 0.01f / 2.f;
return (linear <= 0.0f) ? mid_interval
: Powf(10.0f, 2.f * (MIN(linear, 1.f) - 1.0f));
} }
static float ToLinearLog100Sqrt10(float gamma) { static float ToLinearLog100Sqrt10(float gamma) {
return (gamma < 0.00316227766f) ? 0.0f // The function is non-bijective so choose the middle of [0, 0.00316227766f[.
: 1.0f + Log10f(MIN(gamma, 1.f)) / 2.5f; const float mid_interval = 0.00316227766f / 2.f;
return (gamma <= 0.0f) ? mid_interval
: Powf(10.0f, 2.5f * (MIN(gamma, 1.f) - 1.0f));
} }
static float FromLinearLog100Sqrt10(float linear) { static float FromLinearLog100Sqrt10(float linear) {
// The function is non-bijective so choose the middle of [0, 0.00316227766f[. return (linear < 0.00316227766f) ? 0.0f
const float mid_interval = 0.00316227766f / 2.f; : 1.0f + Log10f(MIN(linear, 1.f)) / 2.5f;
return (linear <= 0.0f) ? mid_interval
: Powf(10.0f, 2.5f * (MIN(linear, 1.f) - 1.0f));
} }
static float ToLinearIec61966(float gamma) { static float ToLinearIec61966(float gamma) {
@ -282,11 +282,11 @@ static float FromLinearPq(float linear) {
} }
static float ToLinearSmpte428(float gamma) { static float ToLinearSmpte428(float gamma) {
return Powf(0.91655527974030934f * MAX(gamma, 0.f), 1.f / 2.6f); return Powf(MAX(gamma, 0.f), 2.6f) / 0.91655527974030934f;
} }
static float FromLinearSmpte428(float linear) { static float FromLinearSmpte428(float linear) {
return Powf(MAX(linear, 0.f), 2.6f) / 0.91655527974030934f; return Powf(0.91655527974030934f * MAX(linear, 0.f), 1.f / 2.6f);
} }
// Conversion in BT.2100 requires RGB info. Simplify to gamma correction here. // Conversion in BT.2100 requires RGB info. Simplify to gamma correction here.