Add HeightMapShape3D update with Image data

Adds HeightMapShape3D update with Image data.

doc/classes/HeightMapShape3D.xml

@@ -6,6 +6,19 @@
 	<description>
 		A 3D heightmap shape, intended for use in physics. Usually used to provide a shape for a [CollisionShape3D]. This is useful for terrain, but it is limited as overhangs (such as caves) cannot be stored. Holes in a [HeightMapShape3D] are created by assigning very low values to points in the desired area.
 		[b]Performance:[/b] [HeightMapShape3D] is faster to check collisions against than [ConcavePolygonShape3D], but it is significantly slower than primitive shapes like [BoxShape3D].
+		A heightmap collision shape can also be build by using an [Image] reference:
+		[codeblocks]
+		[gdscript]
+		var heightmap_texture: Texture = ResourceLoader.load("res://heightmap_image.png")
+		var heightmap_image: Image = heightmap_texture.get_image()
+		heightmap_image.convert(Image.FORMAT_RF)
+
+		var height_min: float = 0.0
+		var height_max: float = 10.0
+
+		update_map_data_from_image(heightmap_image, height_min, height_max)
+		[/gdscript]
+		[/codeblocks]
 	</description>
 	<tutorials>
 	</tutorials>
@@ -20,6 +33,16 @@
 			<return type="float" />
 			<description>
 				Returns the smallest height value found in [member map_data]. Recalculates only when [member map_data] changes.
+		</method>
+		<method name="update_map_data_from_image">
+			<return type="void" />
+			<param index="0" name="image" type="Image" />
+			<param index="1" name="height_min" type="float" />
+			<param index="2" name="height_max" type="float" />
+			<description>
+				Updates [member map_data] with data read from an [Image] reference in [constant Image.FORMAT_RF] format. Automatically resize heightmap [member map_width] and [member map_depth] to fit the full image width and height.
+				Each image pixel is read in as a float on the range from [code]0.0[/code] (black pixel) to [code]1.0[/code] (white pixel). This range value gets remapped to [param height_min] and [param height_max] to form the final height value.
+				[b]Performance:[/b] The image data needs to be received from the GPU, stalling the [RenderingServer] in the process. This can have a noticeable frame rate impact at runtime when the image update is used frequently or with high resolution images.
 			</description>
 		</method>
 	</methods>

scene/resources/height_map_shape_3d.cpp

@@ -30,6 +30,7 @@
 
 #include "height_map_shape_3d.h"
 
+#include "core/io/image.h"
 #include "servers/physics_server_3d.h"
 
 Vector<Vector3> HeightMapShape3D::get_debug_mesh_lines() const {
@@ -187,6 +188,48 @@ real_t HeightMapShape3D::get_max_height() const {
 	return max_height;
 }
 
+void HeightMapShape3D::update_map_data_from_image(const Ref<Image> &p_image, real_t p_height_min, real_t p_height_max) {
+	ERR_FAIL_COND(p_image.is_null());
+	ERR_FAIL_COND(p_image->get_format() != Image::FORMAT_RF);
+	ERR_FAIL_COND(p_image->get_width() < 2);
+	ERR_FAIL_COND(p_image->get_height() < 2);
+	ERR_FAIL_COND(p_height_min > p_height_max);
+
+	map_width = p_image->get_width();
+	map_depth = p_image->get_height();
+	map_data.resize(map_width * map_depth);
+
+	real_t new_min_height = p_height_max;
+	real_t new_max_height = p_height_min;
+
+	float remap_height_min = float(p_height_min);
+	float remap_height_max = float(p_height_max);
+
+	const float *image_data_ptr = (float *)p_image->get_data().ptr();
+	real_t *map_data_ptrw = map_data.ptrw();
+
+	for (int i = 0; i < map_data.size(); i++) {
+		DEV_ASSERT(image_data_ptr[i] >= 0.0 && image_data_ptr[i] <= 1.0);
+		real_t height_value = Math::remap(image_data_ptr[i], 0.0f, 1.0f, remap_height_min, remap_height_max);
+
+		if (height_value < new_min_height) {
+			new_min_height = height_value;
+		}
+
+		if (height_value > new_max_height) {
+			new_max_height = height_value;
+		}
+
+		map_data_ptrw[i] = height_value;
+	}
+
+	min_height = new_min_height;
+	max_height = new_max_height;
+
+	_update_shape();
+	emit_changed();
+}
+
 void HeightMapShape3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_map_width", "width"), &HeightMapShape3D::set_map_width);
 	ClassDB::bind_method(D_METHOD("get_map_width"), &HeightMapShape3D::get_map_width);
@@ -197,6 +240,8 @@ void HeightMapShape3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_min_height"), &HeightMapShape3D::get_min_height);
 	ClassDB::bind_method(D_METHOD("get_max_height"), &HeightMapShape3D::get_max_height);
 
+	ClassDB::bind_method(D_METHOD("update_map_data_from_image", "image", "height_min", "height_max"), &HeightMapShape3D::update_map_data_from_image);
+
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "map_width", PROPERTY_HINT_RANGE, "0.001,100,0.001,or_greater"), "set_map_width", "get_map_width");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "map_depth", PROPERTY_HINT_RANGE, "0.001,100,0.001,or_greater"), "set_map_depth", "get_map_depth");
 	ADD_PROPERTY(PropertyInfo(Variant::PACKED_FLOAT32_ARRAY, "map_data"), "set_map_data", "get_map_data");

scene/resources/height_map_shape_3d.h

@@ -33,6 +33,8 @@
 
 #include "scene/resources/shape_3d.h"
 
+class Image;
+
 class HeightMapShape3D : public Shape3D {
 	GDCLASS(HeightMapShape3D, Shape3D);
 
@@ -57,6 +59,8 @@ class HeightMapShape3D : public Shape3D {
 	real_t get_min_height() const;
 	real_t get_max_height() const;
 
+	void update_map_data_from_image(const Ref<Image> &p_image, real_t p_height_min, real_t p_height_max);
+
 	virtual Vector<Vector3> get_debug_mesh_lines() const override;
 	virtual real_t get_enclosing_radius() const override;