Make the lobby scene dark and add a bit of colour (#1968)

* improve appearance of the lobby scene

* more descriptive comments in lobby frag

* english (unamerican)

alvr/client_core/cpp/graphics.cpp

@@ -252,29 +252,54 @@ uniform lowp int Mode;
 void main()
 {
     if(Mode == 0){                                      // ground
-        lowp vec3 groundCenter = vec3(1.0, 1.0, 1.0);
-        lowp vec3 groundHorizon = vec3(1.0, 1.0, 1.0);
+        lowp vec3 groundCenter = vec3(0.0, 0.0, 0.00);
+        lowp vec3 groundHorizon = vec3(0.00, 0.00, 0.015);
+
+        lowp vec3 gridClose = vec3(0.114, 0.545, 0.804);
+        lowp vec3 gridFar = vec3(0.259, 0.863, 0.886);
+
+        lowp float lineFadeStart = 10.0;
+        lowp float lineFadeEnd = 50.0;
+        lowp float lineFadeDist = lineFadeEnd - lineFadeStart;
+
+        lowp float lineBloom = 10.0;
 
         lowp float distance = length(position.xz);
+
         // Pick a coordinate to visualize in a grid
         lowp vec2 coord = position.xz / 2.0;
+
         // Compute anti-aliased world-space grid lines
         lowp vec2 grid = abs(fract(coord - 0.5) - 0.5) / fwidth(coord);
-        lowp float line = min(grid.x, grid.y);
-        outColor.rgb = vec3(min(line, 1.0) * (1.0 - exp(-distance / 5.0 - 0.01) / 4.0)) * groundCenter;
-        if(distance > 3.0){
-            lowp float coef = 1.0 - 3.0 / distance;
+
+        // Create mask for grid lines and fade over distance
+        lowp float line = clamp(1.0 - min(grid.x, grid.y), 0.0, 1.0);
+        line *= clamp((lineFadeStart - distance) / lineFadeDist, 0.0, 1.0);
+
+        // Fill in normal ground colour
+        outColor.rgb = groundCenter * (1.0 - line);
+
+        // Add cheap and simple "bloom" to the grid lines
+        line *= 1.0 + lineBloom;
+
+        // Fill in grid line colour
+        outColor.rgb += line * mix(gridFar, gridClose, clamp((lineFadeEnd - distance) / lineFadeEnd, 0.0, 1.0));
+
+        // Fade to the horizon colour over distance
+        if(distance > 10.0){
+            lowp float coef = 1.0 - 10.0 / distance;
             outColor.rgb = (1.0 - coef) * outColor.rgb + coef * groundHorizon;
         }
+
         outColor.a = 1.0;
     } else if(Mode == 1) {                             // text
-        lowp vec3 textColor = vec3(0.0, 0.0, 0.0);
+        lowp vec3 textColor = vec3(1.0, 1.0, 1.0);
 
         outColor.rgb = textColor;
         outColor.a = texture(sTexture, uv).a;
     } else {                                           // sky
-        lowp vec3 skyCenter = vec3(0.95, 0.95, 0.95);
-        lowp vec3 skyHorizon = vec3(1.0, 1.0, 1.0);
+        lowp vec3 skyCenter = vec3(0.0, 0.0, 0.0);
+        lowp vec3 skyHorizon = vec3(0.0, 0.0, 0.02);
 
         lowp float coef = 1.0;
         if(position.y < 50.0){
@@ -287,9 +312,6 @@ void main()
         outColor.a = 1.0;
         outColor.rgb = skyCenter * coef + skyHorizon * (1.0 - coef);
     }
-
-    // invert. looks good only for black and white
-    outColor.rgb = 1.0 - outColor.rgb;
 }
 )glsl";