nuclear@6: #include <algorithm>
nuclear@6: #include "xfermap.h"
nuclear@6: 
nuclear@6: TransferFunc::~TransferFunc()
nuclear@6: {
nuclear@6: }
nuclear@6: 
nuclear@6: 
nuclear@6: // ---- TransferWindow ----
nuclear@6: 
nuclear@6: TransferWindow::TransferWindow()
nuclear@6: {
nuclear@6: 	soft_rad = 0.5;
nuclear@6: 	for(int i=0; i<4; i++) {
nuclear@6: 		low[i] = 0.5;
nuclear@6: 		high[i] = 2.0;
nuclear@6: 	}
nuclear@6: }
nuclear@6: 
nuclear@6: void TransferWindow::set_interval(float a, float b)
nuclear@6: {
nuclear@6: 	float v0 = std::min(a, b);
nuclear@6: 	float v1 = std::max(a, b);
nuclear@6: 
nuclear@6: 	for(int i=0; i<4; i++) {
nuclear@6: 		low[i] = v0;
nuclear@6: 		high[i] = v1;
nuclear@6: 	}
nuclear@6: }
nuclear@6: 
nuclear@6: void TransferWindow::set_interval(float *rgba_low, float *rgba_high)
nuclear@6: {
nuclear@6: 	for(int i=0; i<4; i++) {
nuclear@6: 		low[i] = std::min(rgba_low[i], rgba_high[i]);
nuclear@6: 		high[i] = std::max(rgba_low[i], rgba_high[i]);
nuclear@6: 	}
nuclear@6: }
nuclear@6: 
nuclear@6: void TransferWindow::set_interval_rgba(int channel, float a, float b)
nuclear@6: {
nuclear@6: 	low[channel] = std::min(a, b);
nuclear@6: 	high[channel] = std::max(a, b);
nuclear@6: }
nuclear@6: 
nuclear@6: void TransferWindow::set_soft_radius(float s)
nuclear@6: {
nuclear@6: 	soft_rad = s;
nuclear@6: }
nuclear@6: 
nuclear@6: float TransferWindow::get_soft_radius() const
nuclear@6: {
nuclear@6: 	return soft_rad;
nuclear@6: }
nuclear@6: 
nuclear@6: static inline float smoothstep(float a, float b, float x)
nuclear@6: {
nuclear@6: 	if(x < a) return 0.0f;
nuclear@6: 	if(x >= b) return 1.0f;
nuclear@6: 
nuclear@6: 	float t = (x - a) / (b - a);
nuclear@6: 	return t * t * (3.0f - 2.0f * t);
nuclear@6: }
nuclear@6: 
nuclear@6: float TransferWindow::map(float x) const
nuclear@6: {
nuclear@6: 	return smoothstep(low[3] - soft_rad, high[3] - soft_rad, x) *
nuclear@6: 		(1.0 - smoothstep(low[3] + soft_rad, high[3] + soft_rad, x));
nuclear@6: }
nuclear@6: 
nuclear@6: void TransferWindow::map(float x, float *rgba_value) const
nuclear@6: {
nuclear@6: 	for(int i=0; i<4; i++) {
nuclear@6: 		float val = smoothstep(low[i] - soft_rad, high[i] - soft_rad, x);
nuclear@6: 		val *= 1.0 - smoothstep(low[i] + soft_rad, high[i] + soft_rad, x);
nuclear@6: 		rgba_value[i] = val;
nuclear@6: 	}
nuclear@6: }