added frame data caching to speed up container drawing in large trees

src/gui_base.cpp

@@ -116,6 +116,19 @@ bool nov_gui_manager::draw_specific(nov_container* container)
     // return if this container is invalid
     if (container == 0x0) return false;
 
+    // first, check if this container has been cached. if it has, then use the cached data, otherwise
+    // calculate it from scratch
+    for (nov_frame_cache fc : frame_cache)
+    {
+        if (fc.container == container)
+        {
+            draw_container(container, fc.frame_data);
+            return true;
+        }
+    }
+
+    com_1 << "when drawing frame " << stream::mode::HEX << (uint32_t)container << " found no cached data." << stream::endl;
+
     // return if this container has no parent and is not the root container
     if (container->parent == 0x0 && container != root_container) return false;
 
@@ -150,6 +163,7 @@ bool nov_gui_manager::draw_specific(nov_container* container)
 
     // now, draw current container and all children
     draw_container(current, current_frame_data);
+    frame_cache.push(nov_frame_cache{ current_frame_data, container });
 
     return true;
 }

src/include/array.h

@@ -28,13 +28,22 @@ class nov_array
     // is this object valid/initialised
     bool is_valid = false;
 public:
+    struct nov_array_iterator
+    {
+        uint32_t index = 0;
+        nov_array<T>* target = 0x0;
+
+        inline void operator++() { index++; }
+        inline bool operator!=(const nov_array_iterator& other) { return other.index == index; }
+        inline T operator*() { return (*target)[index]; }
+    };
+
     /**
      * extend the array to have a greater capacity to fit more items in.
      * requests memory from malloc and sets up the array container slots ready for them to be `push`ed into
      * 
      * @param new_capacity desired total number of slots in the array (i.e. this function will ensure there
      * is this much capacity in the array)
-     * 
      * **/
     inline void resize(uint32_t new_capacity)
     {
@@ -73,11 +82,10 @@ class nov_array
      * access element by index from the array
      * 
      * @param index index into the array to access
-     * 
      * **/
     inline T& operator[](uint32_t index)
     {
-        if (index >= length) panic(); // crashes the kernel
+        if (index >= length) { com_1 << "index out of range " << index << stream::endl; panic(); } // crashes the kernel
         // step over the linked list until we reach the block which contains the relevant index
         nov_array_container* current = first;
         uint32_t cumulative = 0;
@@ -95,11 +103,10 @@ class nov_array
      * access element by index from the array
      * 
      * @param index index into the array to access
-     * 
      * **/
     inline T operator[](uint32_t index) const
     {
-        if (index >= length) panic(); // crashes the kernel
+        if (index >= length) { com_1 << "index out of range " << index << stream::endl; panic(); } // crashes the kernel
         // step over the linked list until we reach the block which contains the relevant index
         nov_array_container* current = first;
         uint32_t cumulative = 0;
@@ -117,7 +124,6 @@ class nov_array
      * insert an element into the back of the list
      * 
      * @param element element data to insert
-     * 
      * **/
     inline void push(T element)
     {
@@ -138,19 +144,17 @@ class nov_array
      * remove an item from the end of the array, and return its value
      * 
      * @return value of the last item in the array before the pop, or NULL if the array has no elements
-     * 
      * **/
     inline T pop()
     {
-        if (length == 0) panic(); // crashes the kernel
+        if (length == 0) { com_1 << "illegal pop attempt" << stream::endl; panic(); } // crashes the kernel
         T value = (*this)[length-1];
         length--;
         return value;
     }
 
     /**
      * clear the array of all of its items
-     * 
      * **/
     inline void clear()
     {
@@ -160,6 +164,9 @@ class nov_array
     inline uint32_t get_length() const { return length; }
     inline uint32_t get_capacity() const { return capacity; }
 
+    inline nov_array_iterator begin() { return nov_array_iterator{ 0, this }; }
+    inline nov_array_iterator end() { return nov_array_iterator{ get_length()-1, this }; }
+
     inline constexpr nov_array(uint32_t _capacity)
     {
         // clear all values, then request a resize to the desired capacity
@@ -196,4 +203,9 @@ class nov_array
     }
 };
 
+template <typename T>
+auto begin(nov_array<T>& arr) { return arr.begin(); }
+template <typename T>
+auto end(nov_array<T>& arr) { return arr.end(); }
+
 }

src/include/gui/gui_base.h

@@ -5,6 +5,7 @@
 #include <vector.h>
 #include <colour.h>
 #include <graphics.h>
+#include <array.h>
 
 #define draw_function_stub (const nov_frame_data& frame, const graphics::nov_framebuffer& framebuffer, nov_panel* panel)
 
@@ -75,6 +76,15 @@ struct nov_container
     nov_fvector2 division;
 };
 
+/**
+ * contains information about a cached frame and the container pointer it is relevant to
+ * **/
+struct nov_frame_cache
+{
+    nov_frame_data frame_data;      // cached (pre-calculated) frame data
+    nov_container* container;       // pointer to the container for which this is relevant
+};
+
 /**
  * computes the frame data for two child frames based on a parent frame. does the maths to
  * split the parent in half using the division factor
@@ -110,6 +120,8 @@ class nov_gui_manager
     nov_frame_data root_container_frame;
     // information about the current framebuffer being drawn into
     graphics::nov_framebuffer framebuffer;
+    // array of cached information about the container tree
+    nov_array<nov_frame_cache> frame_cache;
 
     /**
      * draw a container, calling draw on the panel inside it if it has one, then drawing its children