fix antialiasing for texture atlas

by enabling centroid sampling for texture coordinates

assets/shaders/3d/terrain/fragment.glsl

@@ -1,5 +1,5 @@
 in vec3 fragmentPosition;
-in vec2 fragmentTextureCoordinates;
+centroid in vec2 fragmentTextureCoordinates;
 in float fragmentTextureIndex;
 in vec3 fragmentColor;