day-night loop, dynamic skybox, clock on debug panel

res/shaders/main.glslf

@@ -3,20 +3,23 @@
 in vec4 a_color;
 in vec2 a_texCoord;
 in float a_distance;
+in vec3 a_dir;
 out vec4 f_color;
 
 uniform sampler2D u_texture0;
+uniform samplerCube u_cubemap;
 uniform vec3 u_fogColor;
 uniform float u_fogFactor;
 uniform float u_fogCurve;
 
 void main(){
+	vec3 fogColor = texture(u_cubemap, a_dir).rgb;
 	vec4 tex_color = texture(u_texture0, a_texCoord);
 	float depth = (a_distance/256.0);
 	float alpha = a_color.a * tex_color.a;
 	// anyway it's any alpha-test alternative required
 	if (alpha < 0.1f)
 		discard;
-	f_color = mix(a_color * tex_color, vec4(u_fogColor,1.0), min(1.0, pow(depth*u_fogFactor, u_fogCurve)));
+	f_color = mix(a_color * tex_color, vec4(fogColor,1.0), min(1.0, pow(depth*u_fogFactor, u_fogCurve)));
 	f_color.a = alpha;
 }