Added camera relative UI support.

src/dawn/scene/components/ui/UICanvas.cpp

@@ -36,6 +36,31 @@ float_t UICanvas::getContentHeight() {
   return this->getHeight();
 }
 
+void UICanvas::getProjectionAndView(glm::mat4 *proj, glm::mat4 *view) {
+  assertNotNull(proj);
+  assertNotNull(view);
+  
+  switch(this->drawType) {
+    case UI_DRAW_TYPE_WORLD_ABSOLUTE:
+      *proj = camera->getProjection();
+      *view = camera->transform->getWorldTransform();
+      break;
+
+    case UI_DRAW_TYPE_WORLD_CAMERA_RELATIVE:
+      *proj = glm::ortho(
+        0.0f,
+        camera->getRenderTarget()->getWidth(),
+        camera->getRenderTarget()->getHeight(),
+        0.0f
+      );
+      *view = glm::mat4(1.0f);
+      break;
+
+    default:
+      assertUnreachable();
+  }
+}
+
 void UICanvas::onStart() {
   if(camera == nullptr) camera = getScene()->findComponent<Camera>();