Clean up the fragment shader

shaders/default.frag

@@ -5,44 +5,14 @@ flat in int TexIndex;
 
 out vec4 FragColor;
 
-uniform sampler2D Texture0;
-uniform sampler2D Texture1;
-uniform sampler2D Texture2;
-uniform sampler2D Texture3;
-uniform sampler2D Texture4;
-uniform sampler2D Texture5;
-uniform sampler2D Texture6;
-uniform sampler2D Texture7;
-uniform sampler2D Texture8;
-uniform sampler2D Texture9;
-uniform sampler2D Texture10;
-uniform sampler2D Texture11;
-uniform sampler2D Texture12;
-uniform sampler2D Texture13;
-uniform sampler2D Texture14;
-uniform sampler2D Texture15;
+uniform sampler2D Textures[16];
 
 void main()
 {
     vec4 outColor = vec4(1.0, 0.0, 0.0, 1.0);
-    switch (int(TexIndex)) {
-        case 0: outColor = texture(Texture0, TexCoord); break;
-        case 1: outColor = texture(Texture1, TexCoord); break;
-        case 2: outColor = texture(Texture2, TexCoord); break;
-        case 3: outColor = texture(Texture3, TexCoord); break;
-        case 4: outColor = texture(Texture4, TexCoord); break;
-        case 5: outColor = texture(Texture5, TexCoord); break;
-        case 6: outColor = texture(Texture6, TexCoord); break;
-        case 7: outColor = texture(Texture7, TexCoord); break;
-        case 8: outColor = texture(Texture8, TexCoord); break;
-        case 9: outColor = texture(Texture9, TexCoord); break;
-        case 10: outColor = texture(Texture10, TexCoord); break;
-        case 11: outColor = texture(Texture11, TexCoord); break;
-        case 12: outColor = texture(Texture12, TexCoord); break;
-        case 13: outColor = texture(Texture13, TexCoord); break;
-        case 14: outColor = texture(Texture14, TexCoord); break;
-        case 15: outColor = texture(Texture15, TexCoord); break;
-        default: outColor = vec4(1.0, 0.0, 0.0, 1.0); break;
+    if (TexIndex >= 0 && TexIndex < 16)
+    {
+        outColor = texture(Textures[TexIndex], TexCoord);
     }
     FragColor = outColor;
 }