improve u_gamma support & update default dense-render-distance value

res/shaders/effect.glslf

@@ -18,6 +18,7 @@ uniform mat4 u_view;
 uniform mat4 u_inverseView;
 uniform vec3 u_sunDir;
 uniform vec3 u_cameraPos;
+uniform float u_gamma;
 
 #include <__effect__>
 

res/shaders/effects/deferred_lighting.glsl

@@ -29,6 +29,8 @@ vec4 effect() {
 
     light = max(light, emission);
 
+    light = pow(light, u_gamma);
+
     vec3 fogColor = texture(u_skybox, dir).rgb;
     float fog = calc_fog(length(u_view * vec4((modelpos.xyz - u_cameraPos) * FOG_POS_SCALE, 0.0)) / 256.0);
     return vec4(mix(texture(u_screen, v_uv).rgb * mix(1.0, light, 1.0), fogColor, fog), 1.0);

res/shaders/lib/shadows.glsl

@@ -35,7 +35,7 @@ float calc_shadow(
         }
         shadow /= 9.0;
     } else {
-        shadow = 0.5;
+        shadow = 0.0;
     }
     return shadow;
 }