nuclear@12: /*
nuclear@12: glviewvol is an OpenGL 3D volume data viewer
nuclear@12: Copyright (C) 2014  John Tsiombikas <nuclear@member.fsf.org>
nuclear@12: 
nuclear@12: This program is free software: you can redistribute it and/or modify
nuclear@12: it under the terms of the GNU General Public License as published by
nuclear@12: the Free Software Foundation, either version 3 of the License, or
nuclear@12: (at your option) any later version.
nuclear@12: 
nuclear@12: This program is distributed in the hope that it will be useful,
nuclear@12: but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@12: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nuclear@12: GNU General Public License for more details.
nuclear@12: 
nuclear@12: You should have received a copy of the GNU General Public License
nuclear@12: along with this program.  If not, see <http://www.gnu.org/licenses/>.
nuclear@12: */
nuclear@7: #include <math.h>
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@7: 	for(int i=0; i<3; i++) {
nuclear@6: 		low[i] = 0.5;
nuclear@7: 		high[i] = 1.5;
nuclear@6: 	}
nuclear@6: }
nuclear@6: 
nuclear@7: void TransferWindow::set_handle(int channel, int handle, float val)
nuclear@7: {
nuclear@7: 	float *dest = handle == HANDLE_LOW ? low : high;
nuclear@7: 
nuclear@7: 	if(channel == -1) {
nuclear@7: 		dest[0] = dest[1] = dest[2] = val;
nuclear@7: 	} else {
nuclear@7: 		dest[channel] = val;
nuclear@7: 	}
nuclear@7: }
nuclear@7: 
nuclear@7: float TransferWindow::get_handle(int channel, int handle) const
nuclear@7: {
nuclear@7: 	const float *src = handle == HANDLE_LOW ? low : high;
nuclear@7: 
nuclear@7: 	if(channel == -1) {
nuclear@7: 		return src[0];	// XXX this doens't make much sense
nuclear@7: 	}
nuclear@7: 	return src[channel];
nuclear@7: }
nuclear@7: 
nuclear@7: int TransferWindow::nearest_handle(int channel, float pos) const
nuclear@7: {
nuclear@7: 	float ldist = 0, hdist = 0;
nuclear@7: 
nuclear@7: 	if(channel == -1) {
nuclear@7: 		for(int i=0; i<3; i++) {
nuclear@7: 			ldist += fabs(low[i] - pos);
nuclear@7: 			hdist += fabs(high[i] - pos);
nuclear@7: 		}
nuclear@7: 	} else {
nuclear@7: 		ldist = fabs(low[channel] - pos);
nuclear@7: 		hdist = fabs(high[channel] - pos);
nuclear@7: 	}
nuclear@7: 	return ldist <= hdist ? HANDLE_LOW : HANDLE_HIGH;
nuclear@7: }
nuclear@7: 
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@7: 	for(int i=0; i<3; 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@7: 	for(int i=0; i<3; 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@7: void TransferWindow::get_interval(float *aptr, float *bptr) const
nuclear@7: {
nuclear@7: 	*aptr = low[0];
nuclear@7: 	*bptr = high[0];
nuclear@7: }
nuclear@7: 
nuclear@7: void TransferWindow::get_interval_rgba(float *rgba_low, float *rgba_high) const
nuclear@7: {
nuclear@7: 	for(int i=0; i<3; i++) {
nuclear@7: 		rgba_low[i] = low[i];
nuclear@7: 		rgba_high[i] = high[i];
nuclear@7: 	}
nuclear@7: }
nuclear@7: 
nuclear@7: void TransferWindow::get_interval_rgba(int channel, float *aptr, float *bptr) const
nuclear@7: {
nuclear@7: 	*aptr = low[channel];
nuclear@7: 	*bptr = high[channel];
nuclear@7: }
nuclear@7: 
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@7: 	float rgb[3];
nuclear@7: 	map(x, rgb);
nuclear@7: 
nuclear@7: 	return std::max(rgb[0], std::max(rgb[1], rgb[2]));
nuclear@6: }
nuclear@6: 
nuclear@7: void TransferWindow::map(float x, float *rgb_value) const
nuclear@6: {
nuclear@7: 	for(int i=0; i<3; i++) {
nuclear@7: 		float val = smoothstep(low[i] - soft_rad, low[i] + soft_rad, x);
nuclear@7: 		val *= 1.0 - smoothstep(high[i] - soft_rad, high[i] + soft_rad, x);
nuclear@7: 		rgb_value[i] = val;
nuclear@6: 	}
nuclear@6: }