opengl 3.3 renderer shaders

shaders/apply_fog.glsl

@@ -0,0 +1,30 @@
+vec3 get_fog_color()
+{
+	vec3 fog_color_v = fog_color;
+	if (lights_count >= 1U && lights[0].type == LIGHT_DIR) {
+		float sun_amount = max(dot(normalize(f_pos.xyz), normalize(-lights[0].dir)), 0.0);
+		fog_color_v += lights[0].color * pow(sun_amount, 30.0);
+	}
+	return fog_color_v;
+}
+
+float get_fog_amount()
+{
+	float z = length(f_pos.xyz);
+//	float fog_amount_v = 1.0 - z * fog_density; // linear
+//	float fog_amount_v = exp( -fog_density * z ); // exp
+	float fog_amount_v = exp2( -fog_density * fog_density * z * z * 1.442695 ); // exp2
+
+	fog_amount_v = 1.0 - clamp(fog_amount_v, 0.0, 1.0);
+	return fog_amount_v;
+}
+
+vec3 apply_fog(vec3 color)
+{
+	return mix(color, get_fog_color(), get_fog_amount());
+}
+
+vec3 add_fog(vec3 color, float amount)
+{
+	return color + get_fog_color() * get_fog_amount() * amount;
+}