Center the image in 3D (#40)

Proc3D.tscn

@@ -6,21 +6,21 @@
 [node name="Proc3D" type="Spatial"]
 
 [node name="Camera" type="Camera" parent="."]
-transform = Transform( 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 2.18523 )
+transform = Transform( 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.681981, 3.2168 )
 fov = 92.2227
 
 [node name="SpatialTree" type="Spatial" parent="."]
-transform = Transform( 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.533641, 0 )
+transform = Transform( 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1.29621, 0 )
 script = ExtResource( 1 )
 
 [node name="NativeHelp" type="Spatial" parent="SpatialTree"]
 script = ExtResource( 2 )
-base/axiom = "X"
+base/delta = 22.5
 base/stroke_length = 10.0
+base/rules = "F:FF-[-F+F+F]+[+F-F-F]"
+base/axiom = "F"
+base/n = 4
 base/stroke_width = 4.0
-base/n = 7
-base/delta = 25.7
-base/rules = "X:F[+X][-X]FX;F:FF"
 
 [node name="Tween" type="Tween" parent="SpatialTree"]
 repeat = true

SpatialTree.gd

@@ -1,41 +1,69 @@
 extends Spatial
 
 func _ready():
-	var img:Image = $NativeHelp.make_image()
-	if img == null:
+	var img_with_blank_space:Image = $NativeHelp.make_image()
+	if img_with_blank_space == null:
 		printerr("image wasn't created")
 		return
+	var img = img_with_blank_space.get_rect(img_with_blank_space.get_used_rect())
+
+	var translate_x = 0.5 - _guess_center_along_bottom(img)
 
 	var resize_y_ratio = 1.0 * img.get_height() / img.get_width()
 
 	for rotate_y in [0, 90]:
-		_make_opposite_faces(img, resize_y_ratio, rotate_y)
+		_make_opposite_faces(img, resize_y_ratio, rotate_y, translate_x)
 
 	$Tween.interpolate_property(self,"rotation_degrees:y", 0, 360, 4, Tween.TRANS_LINEAR)
 	$Tween.start()
 
-func _make_opposite_faces(img: Image, resize_y_ratio: float, rot_y: float):
+func _make_opposite_faces(img: Image, resize_y_ratio: float, rot_y: float, translate_x: float):
 	var tex = ImageTexture.new()
 	tex.create_from_image(img)
 
 	var first_sm = SpatialMaterial.new()
 	first_sm.albedo_texture = tex
 	first_sm.flags_transparent = true
 
-	var first_face = _make_mesh_instance(first_sm, resize_y_ratio, rot_y)
+	var first_face = _make_mesh_instance(first_sm, resize_y_ratio, rot_y, translate_x)
 	add_child(first_face)
 
-	var second_face = _make_mesh_instance(first_sm, resize_y_ratio, rot_y, true)
+	var second_face = _make_mesh_instance(first_sm, resize_y_ratio, rot_y, translate_x, true)
 	add_child(second_face)
 
-func _make_mesh_instance(spatial_mat: SpatialMaterial, resize_y_ratio: float, rot_y: float, flip_faces: bool = false):
+func _make_mesh_instance(spatial_mat: SpatialMaterial, resize_y_ratio: float, rot_y: float, translate_x: float, flip_faces: bool = false) -> MeshInstance:
 	var pm = PlaneMesh.new()
-	pm.size = Vector2(pm.size.x, pm.size.y * resize_y_ratio)
+	var size = Vector2(pm.size.x, pm.size.y * resize_y_ratio)
+	pm.size = size
 	var mi = MeshInstance.new()
 	pm.material = spatial_mat
 	mi.mesh = pm
 	mi.rotate_x(deg2rad(90))
 	mi.rotate_y(deg2rad(rot_y))
+	mi.translate(Vector3(translate_x * size.x, 0, 0))
 	if flip_faces:
 		pm.flip_faces = true
 	return mi
+
+
+const DEFAULT_CENTER = 0.5
+# this is a poor approximation of what the "center"
+# of a tree image is assumed to be:  the first pixel
+# which is NOT transparent, along the final row in the
+# image.  the answer is returned as a percentage value
+func _guess_center_along_bottom(img: Image) -> float:
+	if img.is_empty():
+		return DEFAULT_CENTER
+	var w = img.get_width()
+	var last_row = img.get_height() - 1
+	var found_col = 0
+
+	img.lock()
+	for x in range(0,w):
+		var c = img.get_pixel(x,last_row)
+		if c.a != 0:
+			found_col = x
+			break
+	img.unlock()
+
+	return found_col * 1.0 / w * 1.0

gen/README.md

@@ -4,8 +4,3 @@ This rust library provides functionality to draw L-System
 Trees in 2D, and to expose the ImageTexture that will be
 assigned to various meshes made in 3D.
 
-## trivia
-
-We might have written the 3D mesh-assignment using rust
-bindings, but it was hard to understand how to manipulate
-albedo texture on a [spatial material](https://docs.rs/gdnative/0.9.2/gdnative/api/struct.SpatialMaterial.html). 

project.godot

@@ -16,7 +16,7 @@ _global_script_class_icons={
 [application]
 
 config/name="forest"
-run/main_scene="res://Forest.tscn"
+run/main_scene="res://Proc3D.tscn"
 config/icon="res://icon.png"
 
 [display]