Add recursive transformations

src/components/transform.rs

@@ -1,13 +1,16 @@
 use crate::math::{mat4x4::Mat4x4, vec3::Vec3};
 
-use crate::ecs::Component;
+use crate::ecs::{Component, ComponentReference};
 
 ///Transform  component contains function and data to determine the position of the entity
+///
+///Note: rotation is represented as Euler angles using degrees
 #[derive(Debug)]
 pub struct Transform {
     pub position: Vec3,
     pub rotation: Vec3,
     pub scale: Vec3,
+    parent: Option<ComponentReference<Self>>,
 }
 
 impl Default for Transform {
@@ -20,18 +23,7 @@ impl Default for Transform {
                 y: 1.0,
                 z: 1.0,
             },
-        }
-    }
-}
-
-impl Transform {
-    ///Create a new transform instance
-    #[must_use]
-    pub const fn new(position: Vec3, rotation: Vec3, scale: Vec3) -> Self {
-        Self {
-            position,
-            rotation,
-            scale,
+            parent: None,
         }
     }
 }
@@ -45,6 +37,7 @@ impl Component for Transform {
             rotation: Vec3::default(),
             scale: Vec3::new(1.0, 1.0, 1.0),
             position: Vec3::default(),
+            parent: None,
         }
     }
     fn as_any(&self) -> &dyn std::any::Any {
@@ -56,9 +49,52 @@ impl Component for Transform {
 }
 
 impl Transform {
-    ///Returns transformation of the entity
+    ///Create a new transform instance
+    #[must_use]
+    pub const fn new(position: Vec3, rotation: Vec3, scale: Vec3) -> Self {
+        Self {
+            position,
+            rotation,
+            scale,
+            parent: None,
+        }
+    }
+
+    ///Creates a new transform instance, with a parent
+    pub fn with_parent(
+        position: Vec3,
+        rotation: Vec3,
+        scale: Vec3,
+        parent: ComponentReference<Transform>,
+    ) -> Self {
+        Self {
+            position,
+            rotation,
+            scale,
+            parent: Some(parent),
+        }
+    }
+
+    ///Returns transformation of the entity taking transform of the parent into account
     #[must_use]
     pub fn matrix(&self) -> Mat4x4 {
+        if let Some(p) = &self.parent {
+            let parent_mat = p.borrow().matrix();
+            parent_mat * Mat4x4::transform_matrix_euler(&self.position, &self.scale, &self.rotation)
+        } else {
+            Mat4x4::transform_matrix_euler(&self.position, &self.scale, &self.rotation)
+        }
+    }
+
+    //Returns transformation matrix of the entity, without taking the parent transformation into
+    //account
+    #[must_use]
+    pub fn matrix_local(&self) -> Mat4x4 {
         Mat4x4::transform_matrix_euler(&self.position, &self.scale, &self.rotation)
     }
+
+    ///Sets the parent of the entity, applying all parent transformations to this entity
+    pub fn set_parent(mut self, p: ComponentReference<Transform>) {
+        self.parent = Some(p);
+    }
 }