+/* (Re)calculate the sky colors at each vertex */
+void fgSkyColorsInit() {
+ struct fgLIGHT *l;
+ float sun_angle, diff;
+ float outer_red_param, outer_red_amt, outer_red_diff;
+ float middle_red_param, middle_red_amt, middle_red_diff;
+ int i, j;
+
+ l = &cur_light_params;
+
+ printf("Generating the sky colors for each vertex.\n");
+
+ /* setup for the possibility of sunset effects */
+ sun_angle = l->sun_angle * RAD_TO_DEG;
+ printf(" Sun angle in degrees = %.2f\n", sun_angle);
+
+ if ( (sun_angle > 80.0) && (sun_angle < 100.0) ) {
+ /* 0.0 - 0.4 */
+ outer_red_param = (10.0 - fabs(90.0 - sun_angle)) / 25.0;
+ outer_red_diff = outer_red_param / 6.0;
+ } else {
+ outer_red_param = 0.0;
+ outer_red_diff = 0.0;
+ }
+ printf(" outer_red_param = %.2f outer_red_diff = %.2f\n",
+ outer_red_param, outer_red_diff);
+
+ if ( (sun_angle > 85.0) && (sun_angle < 95.0) ) {
+ /* 0.0 - 0.4 */
+ middle_red_param = (5.0 - fabs(90.0 - sun_angle)) / 12.5;
+ middle_red_diff = middle_red_param / 6.0;
+ } else {
+ middle_red_param = 0.0;
+ middle_red_diff = 0.0;
+ }
+ printf(" middle_red_param = %.2f middle_red_diff = %.2f\n",
+ middle_red_param, middle_red_diff);
+
+ /* calculate transition colors between sky and fog */
+ outer_red_amt = outer_red_param;
+ middle_red_amt = middle_red_param;
+
+ for ( i = 0; i < 6; i++ ) {
+ for ( j = 0; j < 3; j++ ) {
+ diff = l->sky_color[j] - l->fog_color[j];
+ inner_color[i][j] = l->sky_color[j] - diff * 0.3;
+ middle_color[i][j] = l->sky_color[j] - diff * 0.9;
+ outer_color[i][j] = l->fog_color[j];
+ }
+ outer_color[i][0] += outer_red_amt;
+ middle_color[i][0] += middle_red_amt;
+ if ( outer_color[i][0] > 1.0 ) { outer_color[i][0] = 1.0; }
+ if ( middle_color[i][0] > 1.0 ) { middle_color[i][0] = 1.0; }
+ inner_color[i][3] = middle_color[i][3] = outer_color[i][3] =
+ l->sky_color[3];
+
+ outer_red_amt -= outer_red_diff;
+ middle_red_amt -= middle_red_diff;
+
+ printf("inner_color[%d] = %.2f %.2f %.2f %.2f\n", i, inner_color[i][0],
+ inner_color[i][1], inner_color[i][2], inner_color[i][3]);
+ printf("middle_color[%d] = %.2f %.2f %.2f %.2f\n", i,
+ middle_color[i][0], middle_color[i][1], middle_color[i][2],
+ middle_color[i][3]);
+ printf("outer_color[%d] = %.2f %.2f %.2f %.2f\n", i,
+ outer_color[i][0], outer_color[i][1], outer_color[i][2],
+ outer_color[i][3]);
+ }
+
+ outer_red_amt = 0.0;
+ middle_red_amt = 0.0;
+
+ for ( i = 6; i < 12; i++ ) {
+
+ for ( j = 0; j < 3; j++ ) {
+ diff = l->sky_color[j] - l->fog_color[j];
+ inner_color[i][j] = l->sky_color[j] - diff * 0.3;
+ middle_color[i][j] = l->sky_color[j] - diff * 0.9;
+ outer_color[i][j] = l->fog_color[j];
+ }
+ outer_color[i][0] += outer_red_amt;
+ middle_color[i][0] += middle_red_amt;
+ if ( outer_color[i][0] > 1.0 ) { outer_color[i][0] = 1.0; }
+ if ( middle_color[i][0] > 1.0 ) { middle_color[i][0] = 1.0; }
+ inner_color[i][3] = middle_color[i][3] = outer_color[i][3] =
+ l->sky_color[3];
+
+ outer_red_amt += outer_red_diff;
+ middle_red_amt += middle_red_diff;
+
+ printf("inner_color[%d] = %.2f %.2f %.2f %.2f\n", i, inner_color[i][0],
+ inner_color[i][1], inner_color[i][2], inner_color[i][3]);
+ printf("middle_color[%d] = %.2f %.2f %.2f %.2f\n", i,
+ middle_color[i][0], middle_color[i][1], middle_color[i][2],
+ middle_color[i][3]);
+ printf("outer_color[%d] = %.2f %.2f %.2f %.2f\n", i,
+ outer_color[i][0], outer_color[i][1], outer_color[i][2],
+ outer_color[i][3]);
+ }
+}
+
+
+/* Initialize the sky structure and colors */
+void fgSkyInit() {
+ fgSkyVerticesInit();
+ fgSkyColorsInit();
+}
+
+