Fix dithered brushing with scale < 1

src/terrain_3d_editor.cpp

@@ -149,18 +149,17 @@ void Terrain3DEditor::_operate_map(Vector3 p_global_position, real_t p_camera_di
 	}
 	Object::cast_to<Node>(_terrain->get_plugin()->get("ui"))->call("set_decal_rotation", rot);
 
-	Vector3 descaled_position = p_global_position / _terrain->get_mesh_vertex_spacing();
-
 	AABB edited_area;
 	edited_area.position = p_global_position - Vector3(brush_size, 0.0f, brush_size) / 2.0f;
 	edited_area.size = Vector3(brush_size, 0.0f, brush_size);
 
-	for (int x = 0; x < brush_size; x++) {
-		for (int y = 0; y < brush_size; y++) {
-			Vector2i brush_offset = Vector2i(x, y) - (Vector2i(brush_size, brush_size) / 2);
-			Vector3 brush_global_position = Vector3(0.5f, 0.f, 0.5f) +
-					Vector3(p_global_position.x + real_t(brush_offset.x), p_global_position.y,
-							p_global_position.z + real_t(brush_offset.y));
+	real_t vertex_spacing = _terrain->get_mesh_vertex_spacing();
+	for (real_t x = 0.f; x < brush_size; x += vertex_spacing) {
+		for (real_t y = 0.f; y < brush_size; y += vertex_spacing) {
+			Vector2 brush_offset = Vector2(x, y) - (Vector2(brush_size, brush_size) / 2.f);
+			Vector3 brush_global_position =
+					Vector3(p_global_position.x + brush_offset.x + .5f, p_global_position.y,
+							p_global_position.z + brush_offset.y + .5f);
 
 			// If we're brushing across a region boundary, possibly add a region, and get the other map
 			int new_region_index = storage->get_region_index(brush_global_position);
@@ -223,11 +222,10 @@ void Terrain3DEditor::_operate_map(Vector3 p_global_position, real_t p_camera_di
 							destf = Math::lerp(srcf, height, brush_alpha * opacity);
 							break;
 						case AVERAGE: {
-							real_t step = _terrain->get_mesh_vertex_spacing();
-							Vector3 left_position = brush_global_position - Vector3(step, 0, 0);
-							Vector3 right_position = brush_global_position + Vector3(step, 0, 0);
-							Vector3 down_position = brush_global_position - Vector3(0, 0, step);
-							Vector3 up_position = brush_global_position + Vector3(0, 0, step);
+							Vector3 left_position = brush_global_position - Vector3(vertex_spacing, 0.f, 0.f);
+							Vector3 right_position = brush_global_position + Vector3(vertex_spacing, 0.f, 0.f);
+							Vector3 down_position = brush_global_position - Vector3(0.f, 0.f, vertex_spacing);
+							Vector3 up_position = brush_global_position + Vector3(0.f, 0.f, vertex_spacing);
 
 							real_t left = srcf, right = srcf, up = srcf, down = srcf;