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ACESlib.Tonescales.ctl
518 lines (395 loc) · 18.8 KB
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ACESlib.Tonescales.ctl
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// <ACEStransformID>urn:ampas:aces:transformId:v1.5:ACESlib.Tonescales.a1.0.3</ACEStransformID>
// <ACESuserName>ACES 1.0 Lib - Tonescales</ACESuserName>
// Textbook monomial to basis-function conversion matrix.
const float M[ 3][ 3] = {
{ 0.5, -1.0, 0.5 },
{ -1.0, 1.0, 0.5 },
{ 0.5, 0.0, 0.0 }
};
struct SplineMapPoint
{
float x;
float y;
};
struct SegmentedSplineParams_c5
{
float coefsLow[6]; // coefs for B-spline between minPoint and midPoint (units of log luminance)
float coefsHigh[6]; // coefs for B-spline between midPoint and maxPoint (units of log luminance)
SplineMapPoint minPoint; // {luminance, luminance} linear extension below this
SplineMapPoint midPoint; // {luminance, luminance}
SplineMapPoint maxPoint; // {luminance, luminance} linear extension above this
float slopeLow; // log-log slope of low linear extension
float slopeHigh; // log-log slope of high linear extension
};
struct SegmentedSplineParams_c9
{
float coefsLow[10]; // coefs for B-spline between minPoint and midPoint (units of log luminance)
float coefsHigh[10]; // coefs for B-spline between midPoint and maxPoint (units of log luminance)
SplineMapPoint minPoint; // {luminance, luminance} linear extension below this
SplineMapPoint midPoint; // {luminance, luminance}
SplineMapPoint maxPoint; // {luminance, luminance} linear extension above this
float slopeLow; // log-log slope of low linear extension
float slopeHigh; // log-log slope of high linear extension
};
const SegmentedSplineParams_c5 RRT_PARAMS =
{
// coefsLow[6]
{ -4.0000000000, -4.0000000000, -3.1573765773, -0.4852499958, 1.8477324706, 1.8477324706 },
// coefsHigh[6]
{ -0.7185482425, 2.0810307172, 3.6681241237, 4.0000000000, 4.0000000000, 4.0000000000 },
{ 0.18*pow(2.,-15), 0.0001}, // minPoint
{ 0.18, 4.8}, // midPoint
{ 0.18*pow(2., 18), 10000.}, // maxPoint
0.0, // slopeLow
0.0 // slopeHigh
};
float segmented_spline_c5_fwd
(
varying float x,
varying SegmentedSplineParams_c5 C = RRT_PARAMS
)
{
const int N_KNOTS_LOW = 4;
const int N_KNOTS_HIGH = 4;
// Check for negatives or zero before taking the log. If negative or zero,
// set to HALF_MIN.
float logx = log10( max(x, HALF_MIN ));
float logy;
if ( logx <= log10(C.minPoint.x) ) {
logy = logx * C.slopeLow + ( log10(C.minPoint.y) - C.slopeLow * log10(C.minPoint.x) );
} else if (( logx > log10(C.minPoint.x) ) && ( logx < log10(C.midPoint.x) )) {
float knot_coord = (N_KNOTS_LOW-1) * (logx-log10(C.minPoint.x))/(log10(C.midPoint.x)-log10(C.minPoint.x));
int j = knot_coord;
float t = knot_coord - j;
float cf[ 3] = { C.coefsLow[ j], C.coefsLow[ j + 1], C.coefsLow[ j + 2]};
// NOTE: If the running a version of CTL < 1.5, you may get an
// exception thrown error, usually accompanied by "Array index out of range"
// If you receive this error, it is recommended that you update to CTL v1.5,
// which contains a number of important bug fixes. Otherwise, you may try
// uncommenting the below, which is longer, but equivalent to, the above
// line of code.
//
// float cf[ 3];
// if ( j <= 0) {
// cf[ 0] = C.coefsLow[0]; cf[ 1] = C.coefsLow[1]; cf[ 2] = C.coefsLow[2];
// } else if ( j == 1) {
// cf[ 0] = C.coefsLow[1]; cf[ 1] = C.coefsLow[2]; cf[ 2] = C.coefsLow[3];
// } else if ( j == 2) {
// cf[ 0] = C.coefsLow[2]; cf[ 1] = C.coefsLow[3]; cf[ 2] = C.coefsLow[4];
// } else if ( j == 3) {
// cf[ 0] = C.coefsLow[3]; cf[ 1] = C.coefsLow[4]; cf[ 2] = C.coefsLow[5];
// } else if ( j == 4) {
// cf[ 0] = C.coefsLow[4]; cf[ 1] = C.coefsLow[5]; cf[ 2] = C.coefsLow[6];
// } else if ( j == 5) {
// cf[ 0] = C.coefsLow[5]; cf[ 1] = C.coefsLow[6]; cf[ 2] = C.coefsLow[7];
// } else if ( j == 6) {
// cf[ 0] = C.coefsLow[6]; cf[ 1] = C.coefsLow[7]; cf[ 2] = C.coefsLow[8];
// }
float monomials[ 3] = { t * t, t, 1. };
logy = dot_f3_f3( monomials, mult_f3_f33( cf, M));
} else if (( logx >= log10(C.midPoint.x) ) && ( logx < log10(C.maxPoint.x) )) {
float knot_coord = (N_KNOTS_HIGH-1) * (logx-log10(C.midPoint.x))/(log10(C.maxPoint.x)-log10(C.midPoint.x));
int j = knot_coord;
float t = knot_coord - j;
float cf[ 3] = { C.coefsHigh[ j], C.coefsHigh[ j + 1], C.coefsHigh[ j + 2]};
// NOTE: If the running a version of CTL < 1.5, you may get an
// exception thrown error, usually accompanied by "Array index out of range"
// If you receive this error, it is recommended that you update to CTL v1.5,
// which contains a number of important bug fixes. Otherwise, you may try
// uncommenting the below, which is longer, but equivalent to, the above
// line of code.
//
// float cf[ 3];
// if ( j <= 0) {
// cf[ 0] = C.coefsHigh[0]; cf[ 1] = C.coefsHigh[1]; cf[ 2] = C.coefsHigh[2];
// } else if ( j == 1) {
// cf[ 0] = C.coefsHigh[1]; cf[ 1] = C.coefsHigh[2]; cf[ 2] = C.coefsHigh[3];
// } else if ( j == 2) {
// cf[ 0] = C.coefsHigh[2]; cf[ 1] = C.coefsHigh[3]; cf[ 2] = C.coefsHigh[4];
// } else if ( j == 3) {
// cf[ 0] = C.coefsHigh[3]; cf[ 1] = C.coefsHigh[4]; cf[ 2] = C.coefsHigh[5];
// } else if ( j == 4) {
// cf[ 0] = C.coefsHigh[4]; cf[ 1] = C.coefsHigh[5]; cf[ 2] = C.coefsHigh[6];
// } else if ( j == 5) {
// cf[ 0] = C.coefsHigh[5]; cf[ 1] = C.coefsHigh[6]; cf[ 2] = C.coefsHigh[7];
// } else if ( j == 6) {
// cf[ 0] = C.coefsHigh[6]; cf[ 1] = C.coefsHigh[7]; cf[ 2] = C.coefsHigh[8];
// }
float monomials[ 3] = { t * t, t, 1. };
logy = dot_f3_f3( monomials, mult_f3_f33( cf, M));
} else { //if ( logIn >= log10(C.maxPoint.x) ) {
logy = logx * C.slopeHigh + ( log10(C.maxPoint.y) - C.slopeHigh * log10(C.maxPoint.x) );
}
return pow10(logy);
}
float segmented_spline_c5_rev
(
varying float y,
varying SegmentedSplineParams_c5 C = RRT_PARAMS
)
{
const int N_KNOTS_LOW = 4;
const int N_KNOTS_HIGH = 4;
const float KNOT_INC_LOW = (log10(C.midPoint.x) - log10(C.minPoint.x)) / (N_KNOTS_LOW - 1.);
const float KNOT_INC_HIGH = (log10(C.maxPoint.x) - log10(C.midPoint.x)) / (N_KNOTS_HIGH - 1.);
// KNOT_Y is luminance of the spline at each knot
float KNOT_Y_LOW[ N_KNOTS_LOW];
for (int i = 0; i < N_KNOTS_LOW; i = i+1) {
KNOT_Y_LOW[ i] = ( C.coefsLow[i] + C.coefsLow[i+1]) / 2.;
};
float KNOT_Y_HIGH[ N_KNOTS_HIGH];
for (int i = 0; i < N_KNOTS_HIGH; i = i+1) {
KNOT_Y_HIGH[ i] = ( C.coefsHigh[i] + C.coefsHigh[i+1]) / 2.;
};
float logy = log10( max(y,1e-10));
float logx;
if (logy <= log10(C.minPoint.y)) {
logx = log10(C.minPoint.x);
} else if ( (logy > log10(C.minPoint.y)) && (logy <= log10(C.midPoint.y)) ) {
unsigned int j;
float cf[ 3];
if ( logy > KNOT_Y_LOW[ 0] && logy <= KNOT_Y_LOW[ 1]) {
cf[ 0] = C.coefsLow[0]; cf[ 1] = C.coefsLow[1]; cf[ 2] = C.coefsLow[2]; j = 0;
} else if ( logy > KNOT_Y_LOW[ 1] && logy <= KNOT_Y_LOW[ 2]) {
cf[ 0] = C.coefsLow[1]; cf[ 1] = C.coefsLow[2]; cf[ 2] = C.coefsLow[3]; j = 1;
} else if ( logy > KNOT_Y_LOW[ 2] && logy <= KNOT_Y_LOW[ 3]) {
cf[ 0] = C.coefsLow[2]; cf[ 1] = C.coefsLow[3]; cf[ 2] = C.coefsLow[4]; j = 2;
}
const float tmp[ 3] = mult_f3_f33( cf, M);
float a = tmp[ 0];
float b = tmp[ 1];
float c = tmp[ 2];
c = c - logy;
const float d = sqrt( b * b - 4. * a * c);
const float t = ( 2. * c) / ( -d - b);
logx = log10(C.minPoint.x) + ( t + j) * KNOT_INC_LOW;
} else if ( (logy > log10(C.midPoint.y)) && (logy < log10(C.maxPoint.y)) ) {
unsigned int j;
float cf[ 3];
if ( logy > KNOT_Y_HIGH[ 0] && logy <= KNOT_Y_HIGH[ 1]) {
cf[ 0] = C.coefsHigh[0]; cf[ 1] = C.coefsHigh[1]; cf[ 2] = C.coefsHigh[2]; j = 0;
} else if ( logy > KNOT_Y_HIGH[ 1] && logy <= KNOT_Y_HIGH[ 2]) {
cf[ 0] = C.coefsHigh[1]; cf[ 1] = C.coefsHigh[2]; cf[ 2] = C.coefsHigh[3]; j = 1;
} else if ( logy > KNOT_Y_HIGH[ 2] && logy <= KNOT_Y_HIGH[ 3]) {
cf[ 0] = C.coefsHigh[2]; cf[ 1] = C.coefsHigh[3]; cf[ 2] = C.coefsHigh[4]; j = 2;
}
const float tmp[ 3] = mult_f3_f33( cf, M);
float a = tmp[ 0];
float b = tmp[ 1];
float c = tmp[ 2];
c = c - logy;
const float d = sqrt( b * b - 4. * a * c);
const float t = ( 2. * c) / ( -d - b);
logx = log10(C.midPoint.x) + ( t + j) * KNOT_INC_HIGH;
} else { //if ( logy >= log10(C.maxPoint.y) ) {
logx = log10(C.maxPoint.x);
}
return pow10( logx);
}
const SegmentedSplineParams_c9 ODT_48nits =
{
// coefsLow[10]
{ -1.6989700043, -1.6989700043, -1.4779000000, -1.2291000000, -0.8648000000, -0.4480000000, 0.0051800000, 0.4511080334, 0.9113744414, 0.9113744414},
// coefsHigh[10]
{ 0.5154386965, 0.8470437783, 1.1358000000, 1.3802000000, 1.5197000000, 1.5985000000, 1.6467000000, 1.6746091357, 1.6878733390, 1.6878733390 },
{segmented_spline_c5_fwd( 0.18*pow(2.,-6.5) ), 0.02}, // minPoint
{segmented_spline_c5_fwd( 0.18 ), 4.8}, // midPoint
{segmented_spline_c5_fwd( 0.18*pow(2.,6.5) ), 48.0}, // maxPoint
0.0, // slopeLow
0.04 // slopeHigh
};
const SegmentedSplineParams_c9 ODT_1000nits =
{
// coefsLow[10]
{ -4.9706219331, -3.0293780669, -2.1262, -1.5105, -1.0578, -0.4668, 0.11938, 0.7088134201, 1.2911865799, 1.2911865799 },
// coefsHigh[10]
{ 0.8089132070, 1.1910867930, 1.5683, 1.9483, 2.3083, 2.6384, 2.8595, 2.9872608805, 3.0127391195, 3.0127391195 },
{segmented_spline_c5_fwd( 0.18*pow(2.,-12.) ), 0.0001}, // minPoint
{segmented_spline_c5_fwd( 0.18 ), 10.0}, // midPoint
{segmented_spline_c5_fwd( 0.18*pow(2.,10.) ), 1000.0}, // maxPoint
3.0, // slopeLow
0.06 // slopeHigh
};
const SegmentedSplineParams_c9 ODT_2000nits =
{
// coefsLow[10]
{ -4.9706219331, -3.0293780669, -2.1262, -1.5105, -1.0578, -0.4668, 0.11938, 0.7088134201, 1.2911865799, 1.2911865799 },
// coefsHigh[10]
{ 0.8019952042, 1.1980047958, 1.5943000000, 1.9973000000, 2.3783000000, 2.7684000000, 3.0515000000, 3.2746293562, 3.3274306351, 3.3274306351 },
{segmented_spline_c5_fwd( 0.18*pow(2.,-12.) ), 0.0001}, // minPoint
{segmented_spline_c5_fwd( 0.18 ), 10.0}, // midPoint
{segmented_spline_c5_fwd( 0.18*pow(2.,11.) ), 2000.0}, // maxPoint
3.0, // slopeLow
0.12 // slopeHigh
};
const SegmentedSplineParams_c9 ODT_4000nits =
{
// coefsLow[10]
{ -4.9706219331, -3.0293780669, -2.1262, -1.5105, -1.0578, -0.4668, 0.11938, 0.7088134201, 1.2911865799, 1.2911865799 },
// coefsHigh[10]
{ 0.7973186613, 1.2026813387, 1.6093000000, 2.0108000000, 2.4148000000, 2.8179000000, 3.1725000000, 3.5344995451, 3.6696204376, 3.6696204376 },
{segmented_spline_c5_fwd( 0.18*pow(2.,-12.) ), 0.0001}, // minPoint
{segmented_spline_c5_fwd( 0.18 ), 10.0}, // midPoint
{segmented_spline_c5_fwd( 0.18*pow(2.,12.) ), 4000.0}, // maxPoint
3.0, // slopeLow
0.3 // slopeHigh
};
float segmented_spline_c9_fwd
(
varying float x,
varying SegmentedSplineParams_c9 C = ODT_48nits
)
{
const int N_KNOTS_LOW = 8;
const int N_KNOTS_HIGH = 8;
// Check for negatives or zero before taking the log. If negative or zero,
// set to HALF_MIN.
float logx = log10( max(x, HALF_MIN ));
float logy;
if ( logx <= log10(C.minPoint.x) ) {
logy = logx * C.slopeLow + ( log10(C.minPoint.y) - C.slopeLow * log10(C.minPoint.x) );
} else if (( logx > log10(C.minPoint.x) ) && ( logx < log10(C.midPoint.x) )) {
float knot_coord = (N_KNOTS_LOW-1) * (logx-log10(C.minPoint.x))/(log10(C.midPoint.x)-log10(C.minPoint.x));
int j = knot_coord;
float t = knot_coord - j;
float cf[ 3] = { C.coefsLow[ j], C.coefsLow[ j + 1], C.coefsLow[ j + 2]};
// NOTE: If the running a version of CTL < 1.5, you may get an
// exception thrown error, usually accompanied by "Array index out of range"
// If you receive this error, it is recommended that you update to CTL v1.5,
// which contains a number of important bug fixes. Otherwise, you may try
// uncommenting the below, which is longer, but equivalent to, the above
// line of code.
//
// float cf[ 3];
// if ( j <= 0) {
// cf[ 0] = C.coefsLow[0]; cf[ 1] = C.coefsLow[1]; cf[ 2] = C.coefsLow[2];
// } else if ( j == 1) {
// cf[ 0] = C.coefsLow[1]; cf[ 1] = C.coefsLow[2]; cf[ 2] = C.coefsLow[3];
// } else if ( j == 2) {
// cf[ 0] = C.coefsLow[2]; cf[ 1] = C.coefsLow[3]; cf[ 2] = C.coefsLow[4];
// } else if ( j == 3) {
// cf[ 0] = C.coefsLow[3]; cf[ 1] = C.coefsLow[4]; cf[ 2] = C.coefsLow[5];
// } else if ( j == 4) {
// cf[ 0] = C.coefsLow[4]; cf[ 1] = C.coefsLow[5]; cf[ 2] = C.coefsLow[6];
// } else if ( j == 5) {
// cf[ 0] = C.coefsLow[5]; cf[ 1] = C.coefsLow[6]; cf[ 2] = C.coefsLow[7];
// } else if ( j == 6) {
// cf[ 0] = C.coefsLow[6]; cf[ 1] = C.coefsLow[7]; cf[ 2] = C.coefsLow[8];
// }
float monomials[ 3] = { t * t, t, 1. };
logy = dot_f3_f3( monomials, mult_f3_f33( cf, M));
} else if (( logx >= log10(C.midPoint.x) ) && ( logx < log10(C.maxPoint.x) )) {
float knot_coord = (N_KNOTS_HIGH-1) * (logx-log10(C.midPoint.x))/(log10(C.maxPoint.x)-log10(C.midPoint.x));
int j = knot_coord;
float t = knot_coord - j;
float cf[ 3] = { C.coefsHigh[ j], C.coefsHigh[ j + 1], C.coefsHigh[ j + 2]};
// NOTE: If the running a version of CTL < 1.5, you may get an
// exception thrown error, usually accompanied by "Array index out of range"
// If you receive this error, it is recommended that you update to CTL v1.5,
// which contains a number of important bug fixes. Otherwise, you may try
// uncommenting the below, which is longer, but equivalent to, the above
// line of code.
//
// float cf[ 3];
// if ( j <= 0) {
// cf[ 0] = C.coefsHigh[0]; cf[ 1] = C.coefsHigh[1]; cf[ 2] = C.coefsHigh[2];
// } else if ( j == 1) {
// cf[ 0] = C.coefsHigh[1]; cf[ 1] = C.coefsHigh[2]; cf[ 2] = C.coefsHigh[3];
// } else if ( j == 2) {
// cf[ 0] = C.coefsHigh[2]; cf[ 1] = C.coefsHigh[3]; cf[ 2] = C.coefsHigh[4];
// } else if ( j == 3) {
// cf[ 0] = C.coefsHigh[3]; cf[ 1] = C.coefsHigh[4]; cf[ 2] = C.coefsHigh[5];
// } else if ( j == 4) {
// cf[ 0] = C.coefsHigh[4]; cf[ 1] = C.coefsHigh[5]; cf[ 2] = C.coefsHigh[6];
// } else if ( j == 5) {
// cf[ 0] = C.coefsHigh[5]; cf[ 1] = C.coefsHigh[6]; cf[ 2] = C.coefsHigh[7];
// } else if ( j == 6) {
// cf[ 0] = C.coefsHigh[6]; cf[ 1] = C.coefsHigh[7]; cf[ 2] = C.coefsHigh[8];
// }
float monomials[ 3] = { t * t, t, 1. };
logy = dot_f3_f3( monomials, mult_f3_f33( cf, M));
} else { //if ( logIn >= log10(C.maxPoint.x) ) {
logy = logx * C.slopeHigh + ( log10(C.maxPoint.y) - C.slopeHigh * log10(C.maxPoint.x) );
}
return pow10(logy);
}
float segmented_spline_c9_rev
(
varying float y,
varying SegmentedSplineParams_c9 C = ODT_48nits
)
{
const int N_KNOTS_LOW = 8;
const int N_KNOTS_HIGH = 8;
const float KNOT_INC_LOW = (log10(C.midPoint.x) - log10(C.minPoint.x)) / (N_KNOTS_LOW - 1.);
const float KNOT_INC_HIGH = (log10(C.maxPoint.x) - log10(C.midPoint.x)) / (N_KNOTS_HIGH - 1.);
// KNOT_Y is luminance of the spline at each knot
float KNOT_Y_LOW[ N_KNOTS_LOW];
for (int i = 0; i < N_KNOTS_LOW; i = i+1) {
KNOT_Y_LOW[ i] = ( C.coefsLow[i] + C.coefsLow[i+1]) / 2.;
};
float KNOT_Y_HIGH[ N_KNOTS_HIGH];
for (int i = 0; i < N_KNOTS_HIGH; i = i+1) {
KNOT_Y_HIGH[ i] = ( C.coefsHigh[i] + C.coefsHigh[i+1]) / 2.;
};
float logy = log10( max( y, 1e-10));
float logx;
if (logy <= log10(C.minPoint.y)) {
logx = log10(C.minPoint.x);
} else if ( (logy > log10(C.minPoint.y)) && (logy <= log10(C.midPoint.y)) ) {
unsigned int j;
float cf[ 3];
if ( logy > KNOT_Y_LOW[ 0] && logy <= KNOT_Y_LOW[ 1]) {
cf[ 0] = C.coefsLow[0]; cf[ 1] = C.coefsLow[1]; cf[ 2] = C.coefsLow[2]; j = 0;
} else if ( logy > KNOT_Y_LOW[ 1] && logy <= KNOT_Y_LOW[ 2]) {
cf[ 0] = C.coefsLow[1]; cf[ 1] = C.coefsLow[2]; cf[ 2] = C.coefsLow[3]; j = 1;
} else if ( logy > KNOT_Y_LOW[ 2] && logy <= KNOT_Y_LOW[ 3]) {
cf[ 0] = C.coefsLow[2]; cf[ 1] = C.coefsLow[3]; cf[ 2] = C.coefsLow[4]; j = 2;
} else if ( logy > KNOT_Y_LOW[ 3] && logy <= KNOT_Y_LOW[ 4]) {
cf[ 0] = C.coefsLow[3]; cf[ 1] = C.coefsLow[4]; cf[ 2] = C.coefsLow[5]; j = 3;
} else if ( logy > KNOT_Y_LOW[ 4] && logy <= KNOT_Y_LOW[ 5]) {
cf[ 0] = C.coefsLow[4]; cf[ 1] = C.coefsLow[5]; cf[ 2] = C.coefsLow[6]; j = 4;
} else if ( logy > KNOT_Y_LOW[ 5] && logy <= KNOT_Y_LOW[ 6]) {
cf[ 0] = C.coefsLow[5]; cf[ 1] = C.coefsLow[6]; cf[ 2] = C.coefsLow[7]; j = 5;
} else if ( logy > KNOT_Y_LOW[ 6] && logy <= KNOT_Y_LOW[ 7]) {
cf[ 0] = C.coefsLow[6]; cf[ 1] = C.coefsLow[7]; cf[ 2] = C.coefsLow[8]; j = 6;
}
const float tmp[ 3] = mult_f3_f33( cf, M);
float a = tmp[ 0];
float b = tmp[ 1];
float c = tmp[ 2];
c = c - logy;
const float d = sqrt( b * b - 4. * a * c);
const float t = ( 2. * c) / ( -d - b);
logx = log10(C.minPoint.x) + ( t + j) * KNOT_INC_LOW;
} else if ( (logy > log10(C.midPoint.y)) && (logy < log10(C.maxPoint.y)) ) {
unsigned int j;
float cf[ 3];
if ( logy > KNOT_Y_HIGH[ 0] && logy <= KNOT_Y_HIGH[ 1]) {
cf[ 0] = C.coefsHigh[0]; cf[ 1] = C.coefsHigh[1]; cf[ 2] = C.coefsHigh[2]; j = 0;
} else if ( logy > KNOT_Y_HIGH[ 1] && logy <= KNOT_Y_HIGH[ 2]) {
cf[ 0] = C.coefsHigh[1]; cf[ 1] = C.coefsHigh[2]; cf[ 2] = C.coefsHigh[3]; j = 1;
} else if ( logy > KNOT_Y_HIGH[ 2] && logy <= KNOT_Y_HIGH[ 3]) {
cf[ 0] = C.coefsHigh[2]; cf[ 1] = C.coefsHigh[3]; cf[ 2] = C.coefsHigh[4]; j = 2;
} else if ( logy > KNOT_Y_HIGH[ 3] && logy <= KNOT_Y_HIGH[ 4]) {
cf[ 0] = C.coefsHigh[3]; cf[ 1] = C.coefsHigh[4]; cf[ 2] = C.coefsHigh[5]; j = 3;
} else if ( logy > KNOT_Y_HIGH[ 4] && logy <= KNOT_Y_HIGH[ 5]) {
cf[ 0] = C.coefsHigh[4]; cf[ 1] = C.coefsHigh[5]; cf[ 2] = C.coefsHigh[6]; j = 4;
} else if ( logy > KNOT_Y_HIGH[ 5] && logy <= KNOT_Y_HIGH[ 6]) {
cf[ 0] = C.coefsHigh[5]; cf[ 1] = C.coefsHigh[6]; cf[ 2] = C.coefsHigh[7]; j = 5;
} else if ( logy > KNOT_Y_HIGH[ 6] && logy <= KNOT_Y_HIGH[ 7]) {
cf[ 0] = C.coefsHigh[6]; cf[ 1] = C.coefsHigh[7]; cf[ 2] = C.coefsHigh[8]; j = 6;
}
const float tmp[ 3] = mult_f3_f33( cf, M);
float a = tmp[ 0];
float b = tmp[ 1];
float c = tmp[ 2];
c = c - logy;
const float d = sqrt( b * b - 4. * a * c);
const float t = ( 2. * c) / ( -d - b);
logx = log10(C.midPoint.x) + ( t + j) * KNOT_INC_HIGH;
} else { //if ( logy >= log10(C.maxPoint.y) ) {
logx = log10(C.maxPoint.x);
}
return pow10( logx);
}