GPT is reall good at generating comments and fixing spelling error

shaders/particle_render.frag

@@ -0,0 +1,14 @@
+#version 300 es
+precision highp float;
+
+in vec3 vColor;
+in float vAlpha;
+in vec2 vQuadCoord;
+
+out vec4 fragColor;
+
+void main() {
+    float dist = length(vQuadCoord);
+    float falloff = smoothstep(1.0, 0.5, dist);
+    fragColor = vec4(vColor, vAlpha * falloff);
+}