cheditor5 특정 이미지 업로드시 검게 출력되는 문제 수정

plugin/editor/cheditor5/popup/js/vertex-shader.glsl

@@ -0,0 +1,10 @@
+// -------------------------------------------------------
+// CHEditor WebGL Vertex Shader
+// -------------------------------------------------------
+attribute vec2 a_position;
+uniform vec2 u_resolution;
+
+void main() {
+    vec2 clipSpace = (a_position / u_resolution * 2.0) - 1.0;
+    gl_Position = vec4(clipSpace * vec2(1, -1), 0, 1);
+}