Add some more WebGl

frontend/src/shaders/cave-fs.glsl

@@ -2,25 +2,25 @@
 
 precision mediump float;
 
-const float smoothing = 10.0;
-const float inf = 1000000.0;
-const float pi = 3.141592654;
+#define SMOOTHING 10.0
+#define INFINITY 10000.0;
+#define LINE_COUNT 100
+
 
 float interpolate(float from, float to, float quotient) {
-    float steppedQ = sin(quotient * pi - pi * 0.5) * 0.5 + 0.5;
-    return from + (to - from) * clamp(steppedQ, 0.0, 1.0);
+    return from + (to - from) * smoothstep(0.0, 1.0, quotient);
 }
 
 vec2 rotate90deg(in vec2 vector) {
     return vec2(-vector.y, vector.x);
 }
 
-struct Line {
+uniform struct Line {
     vec2 from;
   	vec2 to;
     vec2 normal;
     bool isLineEnd;
-}[16] lines;
+}[LINE_COUNT] lines;
 
 float lineDistance(in vec2 position, in Line line, out float h) {
     vec2 pa = position - line.from, ba = line.to - line.from;
@@ -31,85 +31,44 @@ float lineDistance(in vec2 position, in Line line, out float h) {
     return length(delta) * side;
 }
 
-Line endDummyLineFromLine(Line line) {
-    return Line(line.to, line.to + rotate90deg(line.normal), line.normal, false);
-}
-
 float getDistance(in vec2 target) {
-    float minDistance = inf;
+    float positiveMinDistance = INFINITY;
+    float negativeMaxDistance = -INFINITY;
 
     float leftJoinAcuteness = 0.0;
     vec2 splitterLineNormalStart = vec2(-1.0, 0.0);
-    bool skipDistanceToPrevious = true;
-    for (int i = 0; i < lines.length(); i++) {
-        Line current = lines[i];
-
-        Line next;
-        if (current.isLineEnd || i + 1 == lines.length()) {
-            next = endDummyLineFromLine(current);
-        } else {
-            next = lines[i + 1];
-        }
-
-        vec2 splitterLineNormalEnd = rotate90deg(normalize(current.normal + next.normal));
+    for (int i = 0; i < LINE_COUNT - 1; i++) {
+        vec2 splitterLineNormalEnd = rotate90deg(normalize(lines[i].normal + lines[i + 1].normal));
 
         float h;
-        float distanceToCurrent = lineDistance(target, current, h);
-        float rightJoinAcuteness = dot(next.to - current.from, next.normal - current.normal);
+        float distanceToCurrent = lineDistance(target, lines[i], h);
+        float rightJoinAcuteness = dot(lines[i + 1].to - lines[i].from, lines[i + 1].normal - lines[i].normal);
         distanceToCurrent -= interpolate(
-            sign(leftJoinAcuteness) * smoothing,
-            sign(rightJoinAcuteness) * smoothing, h
+            sign(leftJoinAcuteness) * SMOOTHING,
+            sign(rightJoinAcuteness) * SMOOTHING, h
         );
         leftJoinAcuteness = rightJoinAcuteness;
 
         if (
             !(
-                   dot(target - current.from, splitterLineNormalStart * -sign(dot(current.to - current.from, splitterLineNormalStart))) > 0.0 
-                || dot(target - current.to, splitterLineNormalEnd * sign(dot(current.from - current.to, splitterLineNormalEnd))) <= 0.0
-            ) && abs(distanceToCurrent) < abs(minDistance)
+                   dot(target - lines[i].from, splitterLineNormalStart * -sign(dot(lines[i].to - lines[i].from, splitterLineNormalStart))) > 0.0 
+                || dot(target - lines[i].to, splitterLineNormalEnd * sign(dot(lines[i].from - lines[i].to, splitterLineNormalEnd))) <= 0.0
+            )
         ) {
-            minDistance = distanceToCurrent;
+            float distanceToCurrentSign = sign(distanceToCurrent);
+            positiveMinDistance = min(positiveMinDistance, 1.0 / (0.5 + distanceToCurrentSign / 2.0) * distanceToCurrent);
+            negativeMaxDistance = max(negativeMaxDistance, -1.0 / (0.5 - distanceToCurrentSign / 2.0) * distanceToCurrent);
         }
         splitterLineNormalStart = splitterLineNormalEnd;
     }
 
-    return minDistance;
-}
-
-void createWorld() {
-    lines[0] = Line(vec2(0.0, 300.0), vec2(550.0, 140.0), vec2(1.0), false);
-    lines[1] = Line(vec2(550.0, 140.0), vec2(750.0, 130.0), vec2(1.0), false);
-    lines[2] = Line(vec2(750.0, 130.0), vec2(650.0, 230.0), vec2(1.0), false);
-    lines[3] = Line(vec2(650.0, 230.0), vec2(850.0, 230.0), vec2(1.0), false);
-    lines[4] = Line(vec2(850.0, 230.0), vec2(800.0, 150.0), vec2(1.0), false);
-    lines[5] = Line(vec2(800.0, 150.0), vec2(1000.0, 120.0), vec2(1.0), false);
-    lines[6] = Line(vec2(1000.0, 120.0), vec2(1150, 120.0), vec2(1.0), false);
-    lines[7] = Line(vec2(1150, 120.0), vec2(10200, 350.0), vec2(1.0), true);
-    lines[8] = Line(vec2(0.0, 600.0), vec2(550.0, 440.0), vec2(-1.0), false);
-    lines[9] = Line(vec2(550.0, 440.0), vec2(750.0, 430.0), vec2(-1.0), false);
-    lines[10] = Line(vec2(750.0, 430.0), vec2(650.0, 530.0), vec2(-1.0), false);
-    lines[11] = Line(vec2(650.0, 530.0), vec2(850.0, 530.0), vec2(-1.0), false);
-    lines[12] = Line(vec2(850.0, 530.0), vec2(820.0, 450.0), vec2(-1.0), false);
-    lines[13] = Line(vec2(820.0, 450.0), vec2(1000.0, 420.0), vec2(-1.0), false);
-    lines[14] = Line(vec2(1000.0, 420.0), vec2(1150, 420.0), vec2(-1.0), false);
-    lines[15] = Line(vec2(1150, 420.0), vec2(10200, 650.0), vec2(-1.0), true);
-
-    for (int i = 0; i < lines.length(); i++) {
-        vec2 tangent = lines[i].to - lines[i].from;
-        lines[i].normal = normalize(
-            vec2(-lines[i].normal.x * tangent.y, lines[i].normal.x * tangent.x)
-        );
-    }
+    return positiveMinDistance < negativeMaxDistance ? positiveMinDistance : -negativeMaxDistance;
 }
 
 uniform mat3 transform;
 out vec4 fragmentColor;
 
 void main() {
-    createWorld();
-
-    vec3 projectiveXY = vec3(gl_FragCoord.xy, 1.0);
-    vec2 position = (projectiveXY * transform).xy;
-    //fragmentColor = getDistance(position) > 0.0 ? vec4(0.0, 0.0, 0.0, 0.0) : vec4(0.0, 0.0, 0.0, 1.0);
+    vec2 position = (vec3(gl_FragCoord.xy, 1.0) * transform).xy;
     fragmentColor = vec4(vec3(1.0) * clamp(0.0, 1.0, getDistance(position)), 1.0);
 }