dcbab7d58f
Change-Id: I20bff443fe4c9b9330c0a66779218227c48df014 Former-commit-id:fc06265360[formerlyb69d2cad1c] [formerlyfc06265360[formerlyb69d2cad1c] [formerly1b406ecfca[formerly 564b38b30562a371cf0345de572b32ea8f53e82e]]] Former-commit-id:1b406ecfcaFormer-commit-id:47cefd1513[formerlyaa9df46a1d] Former-commit-id:362d34bee0
104 lines
3.3 KiB
GLSL
104 lines
3.3 KiB
GLSL
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float HALF_FLOAT_NaN = 65504.0;
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/**
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* This function takes an index number and caps it to the range 0-1
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*/
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float capIndex(float index) {
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if ( index < 0.0 ) {
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index = 0.0;
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} else if ( index > 1.0 ) {
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index = 1.0;
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}
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return index;
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}
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/**
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* This function linearly finds the index for the rawValue into cmapMin/cmapMax.
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* 65504.0 is treated as NaN for half floats and -1 is returned as special case
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*/
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float findFloatIndex(float rawValue, float cmapMin, float cmapMax) {
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if ( rawValue == HALF_FLOAT_NaN ) {
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return -1.0;
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}
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float index = ((rawValue - cmapMin) / abs(cmapMax-cmapMin));
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return capIndex(index);
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}
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/**
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* This function logarithmically finds the index for the rawValue into cmapMin/cmapMax.
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* 65504.0 is treated as NaN for half floats and -1 is returned as special case
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*/
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float findFloatIndexLog(float rawValue, float cmapMin, float cmapMax, int mirror) {
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if ( rawValue == HALF_FLOAT_NaN ) {
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return -1.0;
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}
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float index = 0.0;
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// is this strictly negative, strictly positive or neg to pos scaling?
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if ( cmapMin >= 0.0 && cmapMax >= 0.0 && mirror!=1) {
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if(rawValue < cmapMin){
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index = 0.0;
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}else{
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// simple calculation
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index = ((log(rawValue) - log(cmapMin)) / abs(log(cmapMax)-log(cmapMin)));
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}
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} else if (cmapMin <= 0.0 && cmapMax <= 0.0 && mirror!=1) {
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index = ((log(rawValue) - log(cmapMax)) / abs(log(cmapMin)-log(cmapMax)));
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} else {
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// special case, neg to pos:
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float colorMapMin = cmapMin;
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float colorMapMax = cmapMax;
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float zeroVal = max(colorMapMax, abs(colorMapMin)) * 0.0001;
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if (mirror==1 && (colorMapMin > 0.0 || colorMapMax < 0.0)) {
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if (colorMapMax < 0.0) {
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colorMapMax = -cmapMax;
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rawValue = -rawValue;
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zeroVal = -colorMapMin;
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} else {
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zeroVal = cmapMin;
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}
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colorMapMin = -cmapMax;
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}
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float leftZero = 0.0;
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float rightZero = 0.0;
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float absLogZeroVal = abs(log(zeroVal));
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rightZero = absLogZeroVal + log(colorMapMax);
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float cmapMax2 = abs(colorMapMin);
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leftZero = absLogZeroVal + log(cmapMax2);
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float zeroIndex = leftZero / (leftZero + rightZero);
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// figure out index for texture val
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float absTextureColor = abs(rawValue);
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if (absTextureColor <= zeroVal) {
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index = zeroIndex;
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} else if (rawValue > 0.0) {
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// positive texture color value, find index from 0 to
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// cmapMax:
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float logTexColor = absLogZeroVal + log(rawValue);
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float texIndex = logTexColor / rightZero;
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index = (zeroIndex + ((1.0 - zeroIndex) * texIndex));
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} else {
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// negative texture color value, find index from 0 to
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// cmapMax:
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float logTexColor = absLogZeroVal + log(absTextureColor);
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float texIndex = logTexColor / leftZero;
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index = (zeroIndex - (zeroIndex * texIndex));
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}
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}
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return capIndex(index);
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}
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/**
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* Given a raw data value linearly determine the index(0-1) into cmapMin/cmapMax
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*/
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float findIndex(float rawValue, float cmapMin, float cmapMax) {
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float index = ((rawValue - cmapMin) / abs(cmapMax-cmapMin));
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return capIndex(index);
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}
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