windows-nt/Source/XPSP1/NT/multimedia/opengl/test/demos/stonehen/atmosphe.cxx
2020-09-26 16:20:57 +08:00

140 lines
2.7 KiB
C++

#include <windows.h>
#include <GL/glu.h>
#ifdef X11
#include <GL/glx.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef WIN32
#include "stonehen.h"
#endif
#define ATMOSPHERE_EXTERN
#include "atmosphe.h"
const Weather clear("Clear", 0.);
const Weather foggy("Foggy", .04, .5, white, Color(.6, .6, 1), white);
const Weather very_foggy("Very Foggy", .25, .5, white, white, white);
const Weather rainy("Rainy", .01, 1., black, Color(.35, .35, .35), black);
Weather weathers[nweathers] = {clear, foggy, very_foggy, rainy};
const float root3_2 = sqrt(3.) / 2.;
inline float clamp(float a, float min = 0, float max = 1)
{
if (a < min) return min;
else if (a > max) return max;
else return a;
}
Weather::Weather()
{
strcpy(name, "No name");
fog_density = 0;
fog_color = white;
fog_spread = 1;
sun_brightness = 1;
light_sun = GL_LIGHT0;
light_ambient = GL_LIGHT1;
sky_top = blue;
sky_bottom = white;
}
Weather::Weather(const char *n, GLfloat fd, GLfloat fs, Color fc,
Color s1, Color s2, GLfloat sb,
GLenum ls, GLenum la)
{
strcpy(name, n);
fog_density = fd;
fog_color = fc;
fog_spread = fs;
sun_brightness = sb;
light_sun = ls;
light_ambient = la;
sky_top = s1;
sky_bottom = s2;
}
Weather::~Weather()
{
}
Weather Weather::operator=(Weather a)
{
strcpy(name, a.name);
fog_density = a.fog_density;
fog_color = a.fog_color;
fog_spread = a.fog_spread;
sun_brightness = a.sun_brightness;
light_sun = a.light_sun;
light_ambient = a.light_ambient;
sky_top = a.sky_top;
sky_bottom = a.sky_bottom;
return *this;
}
void Weather::apply(Point sun)
{
Color c;
if (fog_density != 0) {
glFogf(GL_FOG_DENSITY, fog_density);
glFogfv(GL_FOG_COLOR, fog_color.c);
glFogi(GL_FOG_MODE, GL_EXP2);
}
glLightfv(light_sun, GL_AMBIENT, black.c);
c = white;
c *= sun_brightness;
glLightfv(light_sun, GL_DIFFUSE, c.c);
glLightfv(light_sun, GL_SPECULAR, white.c);
if (sun.pt[2] >= 0.0) glEnable(light_sun);
else glDisable(light_sun);
c = white;
c *= .25;
glLightfv(light_ambient, GL_AMBIENT, c.c);
glLightfv(light_ambient, GL_DIFFUSE, black.c);
glLightfv(light_ambient, GL_SPECULAR, black.c);
glEnable(light_ambient);
}
void Weather::draw_sky(Point sun)
{
Point p;
float c;
Color bottom, top;
if (sun.pt[2] >= .5) c = 1.;
else if (sun.pt[2] >= -.5)
c = sqrt(1. - sun.pt[2]*sun.pt[2])*.5 + sun.pt[2]*root3_2;
else c = 0;
bottom = sky_bottom * c;
top = sky_top * c;
/* This is drawn as a far-away quad */
glBegin(GL_QUADS);
glColor3fv(bottom.c);
glVertex3f(-1, -1, -1);
glVertex3f(1, -1, -1);
glColor3fv(top.c);
glVertex3f(1, 1, -1);
glVertex3f(-1, 1, -1);
glEnd();
}
GLfloat Weather::shadow_blur()
{
return clamp(fog_density * 10.);
}