Add blob and fix some issues

frontend/src/scripts/drawing/shaders/cave-distance-fs.glsl

@@ -3,10 +3,7 @@
 precision mediump float;
 
 #define LINE_COUNT {lineCount}
-#define CAVE_COLOR vec3(0.36, 0.38, 0.76)
-#define AIR_COLOR vec3(0.7)
-#define DISTANCE_SCALE {distanceScale}
-#define DISTANCE_OFFSET {distanceOffset}
+#define BLOB_COUNT {blobCount}
  
 uniform float maxMinDistance; 
 
@@ -17,32 +14,76 @@ uniform float maxMinDistance;
         float fromRadius;
         float toRadius;
     }[LINE_COUNT] lines;
-#endif
 
-in vec2 worldCoordinates;
-out vec4 fragmentColor;
-
-void main() {
-    float realDistance = 0.0;
-
-    #if LINE_COUNT > 0
-        float minDistance = maxMinDistance;
+    void lineMinDistance(vec2 worldCoordinates, inout float minDistance) {
+        minDistance = maxMinDistance;
 
         for (int i = 0; i < LINE_COUNT; i++) {
             vec2 targetFromDelta = worldCoordinates - lines[i].from;
             vec2 toFromDelta = lines[i].toFromDelta;
-            float h = clamp(dot(targetFromDelta, toFromDelta) / dot(toFromDelta, toFromDelta), 0.0, 1.0);
-            float lineDistance = distance(targetFromDelta, toFromDelta * h) - mix(lines[i].fromRadius, lines[i].toRadius, h);
+            
+            float h = clamp(
+                dot(targetFromDelta, toFromDelta) / dot(toFromDelta, toFromDelta),
+                0.0, 1.0
+            );
+
+            float lineDistance = (
+                    distance(targetFromDelta, toFromDelta * h) 
+                - mix(lines[i].fromRadius, lines[i].toRadius, h)
+            );
 
             minDistance = min(minDistance, lineDistance);
         }
 
-        realDistance = -minDistance;
+        minDistance *= -1.0;
+    }
+#endif
+
+#if BLOB_COUNT > 0
+    #define headRadius {headRadius}
+    #define torsoRadius {torsoRadius}
+    #define footRadius {footRadius}
+
+    uniform struct Blob {
+        vec2 headCenter;
+        vec2 torsoCenter;
+        vec2 leftFootCenter;
+        vec2 rightFootCenter;
+    }[BLOB_COUNT] blobs;
+
+    float circleMinDistance(vec2 worldCoordinates, vec2 circleCenter, float radius) {
+        return distance(worldCoordinates, circleCenter) - radius;
+    }
+
+    void blobMinDistance(vec2 worldCoordinates, inout float minDistance) {
+        float k = 1.0;
+
+        for (int i = 0; i < BLOB_COUNT; i++) {
+            float res = exp2(-k * circleMinDistance(worldCoordinates, blobs[i].headCenter, headRadius));
+            res += exp2(-k * circleMinDistance(worldCoordinates, blobs[i].torsoCenter, torsoRadius));
+            res += exp2(-k * circleMinDistance(worldCoordinates, blobs[i].leftFootCenter, footRadius));
+            res += exp2(-k * circleMinDistance(worldCoordinates, blobs[i].rightFootCenter, footRadius));
+
+            minDistance = min(minDistance, -log2(res) / k);
+        }
+    }
+#endif
+
+
+
+in vec2 worldCoordinates;
+out vec2 fragmentColor;
+
+void main() {
+    float minDistance = -maxMinDistance;
+
+    #if LINE_COUNT > 0
+        lineMinDistance(worldCoordinates, minDistance);
     #endif
 
-    fragmentColor = vec4(
-        mix(CAVE_COLOR, AIR_COLOR, clamp(realDistance, 0.0, 1.0)),
-        (realDistance + DISTANCE_OFFSET) / DISTANCE_SCALE
+    #if BLOB_COUNT > 0
+        blobMinDistance(worldCoordinates, minDistance);
+    #endif
 
-    );
+    fragmentColor = vec2(minDistance, 0.0);
 }