add basic antialiasing

Author: II-Day-II

src/shaders/grid.frag

@@ -20,54 +20,38 @@ vec3 grid(vec2 position, float scale, float thickness, float level) {
     const float base_line_width = thickness;
     position += base_line_width / scale / 2.0;
     vec2 grid_pos = mod(position, level);
-    vec2 grid_point = step(grid_pos, vec2(base_line_width / scale)); // ensures constant line size, which I don't want...
-    float grid = min(1.0, grid_point.x + grid_point.y); // float(grid_point.x != 0.0 || grid_point.y != 0.0)
+    vec2 derivative = fwidth(grid_pos);
+    vec2 grid_point = smoothstep(grid_pos - derivative, grid_pos, vec2(base_line_width / scale)); // ensures constant line size
+    float grid = min(1.0, grid_point.x + grid_point.y);
     vec3 col = vec3(grid);
-    if (abs(position.x) < base_line_width / scale) {
-        col = vec3(0.0, 1.0, 0.0); // green at x=0
-    }
-    if (abs(position.y) < base_line_width / scale) {
-        col = vec3(1.0, 0.0, 0.0); // red at y=0
-    }
     return col;
 }
 
 
 void main() {
-    const float logscale = 5.0;
+    const float LOGSCALE = 5.0;
+    const float MAX_LINE_THICKNESS = 0.010;
 
     vec2 offset = (inverse(camera.view_proj) * vec4(uv * 2 - 1, 0.0, 1.0)).xy; // TODO: optimize
-    vec2 derivative = fwidth(offset);
 
-    float grid_level = log(pan_and_zoom.zoom) / log(logscale) + 3.0 + 1.20; // [0, 4] for zoom [0.001, 10]
+    float grid_level = log(pan_and_zoom.zoom) / log(LOGSCALE) + 3.0 + 1.20; // [0, 4] for zoom [0.001, 10] + 1.2 for styling
     uint grid_floor = uint(floor(grid_level));
     uint grid_ceil = uint(ceil(grid_level));
     float t = grid_level - float(grid_floor);
-    //t = t*t;//pow(t,t); // slightly more aggressive fadein
 
-    float thickness0 = (1.0 - t) * 0.010;
-    float thickness1 = (t) * 0.010;
-    float scale0 = pow(logscale, 3.0 - grid_floor);
-    float scale1 = scale0 / logscale;
+    float thickness0 = (1.0 - t) * MAX_LINE_THICKNESS;
+    float thickness1 = (t) * MAX_LINE_THICKNESS;
+    float scale0 = pow(LOGSCALE, 3.0 - grid_floor);
+    float scale1 = scale0 / LOGSCALE;
     vec3 col0 = grid(offset, pan_and_zoom.zoom, thickness0, scale0);
-    //if (col0 == vec3(1.0)){
-    //	col0 = vec3(1,0,0);
-    //}
     vec3 col1 = grid(offset, pan_and_zoom.zoom, thickness1, scale1);
-    //if (col1 == vec3(1.0)) {
-    //	col1 = vec3(0,1,0);
-    //}
     vec3 col = mix(col0, col1, t);
-
-    //vec3 col0 = grid(offset, pan_and_zoom.zoom, 0.005, 100); // grid valid for zoom ~0.001 (unused..?) 0
-    //vec3 col1 = grid(offset, pan_and_zoom.zoom, 0.005, 10); // grid valid for zoom ~0.01               1
-    //vec3 col2 = grid(offset, pan_and_zoom.zoom, 0.005, 1); // grid valid for zoom ~0.1                 2
-    //vec3 col3 = grid(offset, pan_and_zoom.zoom, 0.005, 0.1); // grid valid for zoom ~1                 3
-    //vec3 col4 = grid(offset, pan_and_zoom.zoom, 0.005, 0.01); // grid valid for zoom ~10               4
-    //vec3 grids[5] = {col0, col1, col2, col3, col4};
-
-    //vec3 col = mix(grids[grid_floor], grids[grid_ceil], t);
-
-
+    float thickness = max(thickness0, thickness1);
+    if (abs(offset.x) < thickness / pan_and_zoom.zoom) {
+        col.rb = vec2(0.0);
+    }
+    if (abs(offset.y) < thickness / pan_and_zoom.zoom) {
+        col.gb = vec2(0.0);
+    }
     out_FragColor = vec4(col, 1.0);
 }