13 #include <simgear/compiler.h>
21 unsigned char env_map[TEXRES_X][TEXRES_Y][4];
23 int window_x = 640, window_y = 480;
24 float alpha = 0.0, beta = 0.0;
26 /*****************************************************************/
27 /*****************************************************************/
28 /*****************************************************************/
29 void setColor(float x, float y, float z, float angular_size, float r, float g, float b, float a)
32 float inv_length = 1.0 / sqrt(x*x + y*y + z*z);
33 x *= inv_length; y *= inv_length; z *= inv_length;
34 printf("x = %f, y = %f, z = %f\n", x, y, z);
36 float cos_angular_size = cos(angular_size*3.1415/180.0);
37 printf("cos_angular_size = %f\n", cos_angular_size);
39 for(float tz_sign = -1.0; tz_sign < 3.0; tz_sign += 2.0)
41 for(float tx = -1.0; tx <= 1.0; tx += 0.01)
43 for(float ty = -1.0; ty <= 1.0; ty += 0.01)
45 if ((1.0 - tx*tx - ty*ty)<0.0)
48 float tz = tz_sign * sqrt(1.0 - tx*tx - ty*ty);
50 float cos_phi = x*tx + y*ty + z*tz;
52 if (cos_angular_size < cos_phi)
54 float rx = tx; //mirroring on the z=0 plane
58 float inv_m = 1.0 / (2.0 * sqrt(rx*rx + ry*ry + (rz + 1)*(rz + 1)));
59 int s = (int)(TEXRES_X * (rx * inv_m + 0.5));
60 int t = (int)(TEXRES_Y * (ry * inv_m + 0.5));
62 //seg_fault protection:
64 if (s>=TEXRES_X) s=TEXRES_X-1;
67 if (t>=TEXRES_Y) t=TEXRES_Y-1;
69 env_map[s][t][0] = (unsigned char)(r * 255);
70 env_map[s][t][1] = (unsigned char)(g * 255);
71 env_map[s][t][2] = (unsigned char)(b * 255);
72 env_map[s][t][3] = (unsigned char)(a * 255);
78 /*****************************************************************/
79 /*****************************************************************/
80 /*****************************************************************/
84 glClearColor(0.0, 0.0, 0.0, 0.0);
85 glShadeModel(GL_FLAT);
86 glEnable(GL_DEPTH_TEST);
88 for(int x=0; x<TEXRES_X; x++)
90 for(int y=0; y<TEXRES_Y; y++)
92 env_map[x][y][0] = x; //a few colors
94 env_map[x][y][2] = 128;
95 env_map[x][y][3] = 128;
99 /*****************************************************************/
100 /*****************************************************************/
101 /*****************************************************************/
103 setColor(0.0, 0.0, -1.0 , 23.0, 1.0, 1.0, 1.0, 1.0);
104 setColor(0.7071067, 0.0, -0.7071067, 23.0, 1.0, 0.0, 0.0, 1.0);
105 /*****************************************************************/
106 /*****************************************************************/
107 /*****************************************************************/
109 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
110 glGenTextures(1, &texName);
111 glBindTexture(GL_TEXTURE_2D, texName);
113 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
114 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
115 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
116 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
117 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, TEXRES_X, TEXRES_Y, 0, GL_RGBA, GL_UNSIGNED_BYTE, env_map);
120 void reshape(int w, int h)
122 window_x = w; window_y = h;
123 glViewport(0, 0, (GLsizei) w, (GLsizei) h);
124 glMatrixMode(GL_PROJECTION);
126 gluPerspective((GLdouble) 60.0, ((GLdouble)w)/((GLdouble)h), (GLdouble) 10.0, (GLdouble) 1000.0);
127 glMatrixMode(GL_MODELVIEW);
129 glTranslatef(0.0, 0.0, -20.0);
134 glClear ( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ) ;
137 glMatrixMode(GL_PROJECTION);
139 gluPerspective((GLdouble) 60.0, (float)window_x/window_y, (GLdouble) 1.0, (GLdouble) 100.0);
140 glMatrixMode(GL_MODELVIEW);
143 glTranslatef(0.0, 0.0, -10.0);
145 glRotatef(alpha, 1.0, 0.0, 0.0);
146 glRotatef(beta, 0.0, 1.0, 0.0);
149 glColor3f(1.0, 1.0, 1.0);
150 glVertex3f(0.0, 0.0, 0.0);
151 glVertex3f(0.0, 0.0, 1.0);
154 /*****************************************************************/
155 /*****************************************************************/
156 /*****************************************************************/
157 glEnable(GL_TEXTURE_2D);
158 glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
159 glBindTexture(GL_TEXTURE_2D, texName);
161 glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
162 glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
163 glEnable(GL_TEXTURE_GEN_S);
164 glEnable(GL_TEXTURE_GEN_T);
167 glNormal3f(0.0, 0.0, 1.0);
168 glVertex3f(1.0, 1.0, 0.0);
169 glVertex3f(-1.0, 1.0, 0.0);
170 glVertex3f(-1.0, -1.0, 0.0);
171 glVertex3f(1.0, -1.0, 0.0);
177 glNormal3f(0.0, 0.0, 1.0);
178 glVertex3f(0.0, 0.0, 0.0);
182 glDisable(GL_TEXTURE_GEN_S);
183 glDisable(GL_TEXTURE_GEN_T);
184 glDisable(GL_TEXTURE_2D);
185 /*****************************************************************/
186 /*****************************************************************/
187 /*****************************************************************/
189 //show how the map looks like
190 glMatrixMode(GL_PROJECTION);
192 //gluOrtho2D(0.0 -10.0, 1.0 +10.0, -(float)window_x/window_y -10.0,0.0 +10.0);
193 //glOrtho(0.0, 5.0, -5.0, 0.0, -10.0, 10.0);
194 glOrtho(0.0, 5.0*((float)window_x/window_y), -5.0, 0.0, -10.0, 10.0);
195 glMatrixMode(GL_MODELVIEW);
197 glEnable(GL_TEXTURE_2D);
198 glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
199 glBindTexture(GL_TEXTURE_2D, texName);
202 glTexCoord2f(0.0, 0.0); glVertex3f(0.0, 0.0, 0.0);
203 glTexCoord2f(0.0, 1.0); glVertex3f(0.0, -1.0, 0.0);
204 glTexCoord2f(1.0, 1.0); glVertex3f(1.0, -1.0, 0.0);
205 glTexCoord2f(1.0, 0.0); glVertex3f(1.0, 0.0, 0.0);
208 glDisable(GL_TEXTURE_2D);
210 glutPostRedisplay () ;
214 void keyboard (unsigned char key, int x, int y)
223 if (alpha >= 360.0) alpha -= 360.0;
228 if (alpha < 0.0) alpha += 360.0;
233 if (beta <= -90.0) beta = -90.0;
238 if (beta >= 90.0) beta = 90.0;
242 alpha = 0.0; beta = 0.0;
247 int main(int argc, char** argv)
249 glutInitWindowSize(window_x, window_y);
250 glutInit(&argc, argv);
251 glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
252 glutCreateWindow(argv[0]);
254 glutDisplayFunc(display);
255 glutReshapeFunc(reshape);
256 glutKeyboardFunc(keyboard);