Visual Effects Vol. 1 (#14610)

This PR adds a variety of effects to enhance the visual experience.

    "soft" clouds look
    Tinted shadows
    Crude water reflections (sky and sun) and waves
    Translucent foliage
    Node specular highlights
    Adjusted fog color (more saturated where the fog is lighter)
    Minor changes to volumetric lighting (crudely simulates the effect of depth)

Co-authored-by: sfan5 <sfan5@live.de>

client/shaders/object_shader/opengl_fragment.glsl

@@ -20,6 +20,7 @@ uniform float animationTimer;
 	uniform vec4 CameraPos;
 	uniform float xyPerspectiveBias0;
 	uniform float xyPerspectiveBias1;
+	uniform vec3 shadow_tint;
 
 	varying float adj_shadow_strength;
 	varying float cosLight;
@@ -432,7 +433,7 @@ void main(void)
 		col.rgb =
 				adjusted_night_ratio * col.rgb + // artificial light
 				(1.0 - adjusted_night_ratio) * ( // natural light
-						col.rgb * (1.0 - shadow_int * (1.0 - shadow_color)) +  // filtered texture color
+						col.rgb * (1.0 - shadow_int * (1.0 - shadow_color) * (1.0 - shadow_tint)) +  // filtered texture color
 						dayLight * shadow_color * shadow_int);                 // reflected filtered sunlight/moonlight
 	}
 #endif
@@ -448,7 +449,13 @@ void main(void)
 	// Note: clarity = (1 - fogginess)
 	float clarity = clamp(fogShadingParameter
 		- fogShadingParameter * length(eyeVec) / fogDistance, 0.0, 1.0);
-	col = mix(fogColor, col, clarity);
+	float fogColorMax = max(max(fogColor.r, fogColor.g), fogColor.b);
+	// Prevent zero division.
+	if (fogColorMax < 0.0000001) fogColorMax = 1.0;
+	// For high clarity (light fog) we tint the fog color.
+	// For this to not make the fog color artificially dark we need to normalize using the
+	// fog color's brightest value. We then blend our base color with this to make the fog.
+	col = mix(fogColor * pow(fogColor / fogColorMax, vec4(2.0 * clarity)), col, clarity);
 	col = vec4(col.rgb, base.a);
 
 	gl_FragData[0] = col;