Initial public source release

Split reusable rendering and format support into vectorail-core and vectorail-gc.

apps/desktop/shaders/line.frag

@@ -0,0 +1,39 @@
+#version 450 core
+in float vSide;
+in float vDist;
+in float vTrackTimeMs;
+out vec4 FragColor;
+
+uniform vec3 uColor;
+uniform vec3 uBehindColor;
+uniform bool uIsAvatar;
+uniform bool uClipTrack;
+uniform float uCurrentTimeMs;
+uniform float uDrawBehindMs;
+uniform float uDrawAheadMs;
+uniform float uAlpha;
+
+void main() {
+    float dist = abs(vSide);
+
+    // Мягкий туман: трасса видна очень далеко
+    float fog = exp(-vDist * 0.001);
+
+    if (uClipTrack &&
+        (vTrackTimeMs < uCurrentTimeMs - uDrawBehindMs ||
+         vTrackTimeMs > uCurrentTimeMs + uDrawAheadMs)) {
+        discard;
+    }
+
+    if (uIsAvatar) {
+        FragColor = vec4(1.0, 1.0, 1.0, 1.0);
+    } else {
+        float intensity = pow(1.0 - dist, 4.0);
+        float core = pow(1.0 - dist, 20.0);
+        vec3 railColor = (uClipTrack && vTrackTimeMs < uCurrentTimeMs) ? uBehindColor : uColor;
+        vec3 finalColor = mix(railColor, vec3(1.0), core);
+
+        // Цвет затухает в темноту, а не просто обрезается
+        FragColor = vec4(finalColor * fog, intensity * fog * uAlpha);
+    }
+}