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#ifdef G_OS_WIN32
#define WIN32_LEAN_AND_MEAN 1
#include <windows.h>
#endif
#include <math.h>
#include "funcs.h"
#include "palette.h"
void HSVtoRGB(float *r, float *g, float *b, float h, float s, float v)
{
int i;
float f, p, q, t;
if( s == 0 ) {
// achromatic (grey)
*r = *g = *b = v;
return;
}
h /= 60; // sector 0 to 5
i = floor(h);
f = h - i; // factorial part of h
p = v * (1 - s);
q = v * (1 - s * f);
t = v * (1 - s * (1 - f));
switch(i) {
case 0:
*r = v;
*g = t;
*b = p;
break;
case 1:
*r = q;
*g = v;
*b = p;
break;
case 2:
*r = p;
*g = v;
*b = t;
break;
case 3:
*r = p;
*g = q;
*b = v;
break;
case 4:
*r = t;
*g = p;
*b = v;
break;
default: // case 5:
*r = v;
*g = p;
*b = q;
break;
}
}
// r,g,b values are from 0 to 1
// h = [0,360], s = [0,1], v = [0,1]
// if s == 0, then h = -1 (undefined)
void RGBtoHSV(float r, float g, float b, float *h, float *s, float *v)
{
float min, max, delta;
min = MIN3(r, g, b);
max = MAX3(r, g, b);
*v = max; // v
delta = max - min;
if(max != 0) {
*s = delta / max; // s
} else {
// r = g = b = 0 // s = 0, v is undefined
*s = 0;
*h = -1;
return;
}
if(r == max) {
*h = ( g - b ) / delta; // between yellow & magenta
} else if(g == max) {
*h = 2 + (b - r) / delta; // between cyan & yellow
} else {
*h = 4 + (r - g) / delta; // between magenta & cyan
}
*h *= 60; // degrees
if(*h < 0) {
*h += 360;
}
}
//rainbow: Implements a color palette, mapping the scalar 'value' to a rainbow color RGB
void rainbow(float value, float *R, float *G, float *B)
{
const float dx = 0.8f;
if (value < 0) value = 0;
if (value > 1) value = 1;
value = (6 - 2 * dx) * value + dx;
*R = (float)max(0.0f, (3 - fabs(value - 4.0f) - fabs(value - 5.0f)) / 2.0f);
*G = (float)max(0.0f, (4 - fabs(value - 2.0f) - fabs(value - 4.0f)) / 2.0f);
*B = (float)max(0.0f, (3 - fabs(value - 1.0f) - fabs(value - 2.0f)) / 2.0f);
}
void colormap_fire(float value, float *R, float *G, float *B)
{
/* Colormap Fire
* A fire effect deals with two parts, first a drop from red to yellow (halfway)
* during which time the Red component remains full e.g. 1. The Green component is
* slowly added to turn the red into orange, and then yellow (R & G =Y). After this
* point, the Red and Green component (e.g. yellow) have to drop simulataniously
* to go from yellow down to black.
*/
*B = 0;
*G = 0;
*R = 0;
if (value <= (0.01)) {
/* whilst value is 0 - 0.5 both red and green equally change to create yellow */
*R = *G = value;
} else {
/* whilst value is 0.5 - 1 Red is always fully on while the Green component is
* added in steps to go from red to orange to yellow.
*/
*G = 0.9f - value;
*R = 0.8f; // not 1, makes red deeper, more intense
}
}
//set_palette: Sets three different types of colormaps
struct color4f set_palette(int colormap_sort, float value, int num_colors)
{
float R, G, B;
struct color4f return_value;
const int NLEVELS = 7;
value *= num_colors;
value = (float)(int)(value);
value /= num_colors;
switch (colormap_sort)
{
case PALETTE_BLACKWHITE:
R = G = B = value;
break;
case PALETTE_RAINBOW:
rainbow(value,&R,&G,&B);
break;
case PALETTE_BANDS:
value *= NLEVELS; value = (float)(int)(value); value/= NLEVELS;
rainbow(value,&R,&G,&B);
break;
case PALETTE_BLUE_GREEN_RED:
if (value < -0.1)
{
R = G = 0;
value -= -0.1f;
value /= 0.9f;
B = -value;
}
else if (value < 0.1)
{
R = B = 0;
value += 0.1f;
value /= 0.2f;
G = value;
}
else
{
value -= 0.1f;
value /= 0.9f;
R = value;
G = B = 0;
}
break;
case PALETTE_WILRIK:
colormap_fire(value, &R, &G, &B);
break;
case PALETTE_OLIVER:
rainbow(value, &R, &G, &B);
break;
case PALETTE_RED:
R = 1.0f;
G = B = 0.0f;
break;
case PALETTE_GREEN:
G = 1.0f;
R = B = 0.0f;
break;
case PALETTE_BLUE:
B = 1.0f;
R = G = 0.0f;
break;
}
return_value.r = R;
return_value.g = G;
return_value.b = B;
return return_value;
}
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