improved sand pit material

assets/shaders/horizontal_world_uv.gdshader

@@ -0,0 +1,16 @@
+shader_type spatial;
+
+uniform sampler2D albedo_texture : repeat_enable, filter_nearest, source_color;
+uniform vec2 horizontal_uv_offset = vec2(0.0);
+
+void vertex() {
+	vec3 world_position = (MODEL_MATRIX * vec4(VERTEX, 1.0)).xyz;
+	vec3 world_normal = (MODEL_NORMAL_MATRIX * NORMAL).xyz;
+	vec2 uv_y = world_position.xz + horizontal_uv_offset;
+	//vec3 normal_weights = world_normal / (world_normal.x + world_normal.y + world_normal.z);
+	UV = mix(UV, uv_y, abs(world_normal.y));
+}
+
+void fragment() {
+	ALBEDO = texture(albedo_texture, UV).rgb;
+}