Panning for gold, with the Quadtree!

Sulix celebrates the panning in the quadtree finally working*
with the worst pun yet!

* The segfault doesn't count.

diff --git a/src/quadtree.cpp b/src/quadtree.cpp
index 3d5dbee..b84bb78 100644 (file)
--- a/src/quadtree.cpp
+++ b/src/quadtree.cpp
@@ -70,6 +70,12 @@ QuadTreeIndex QuadTree::GetNeighbour(QuadTreeIndex start, int xdir, int ydir, Do
 {
        if (!xdir && !ydir) return start;
 
+       if (addTo && (nodes[start].parent == -1) && nodes[start].child_type != QTC_UNKNOWN)
+       {
+               Debug("Adding parent of node %d...", start);
+               addTo->GenQuadParent(start, nodes[start].child_type);
+       }
+
        QuadTreeIndex newNode;
        // Try moving to the right if that's easy.
        if (xdir > 0)

diff --git a/src/view.cpp b/src/view.cpp
index 53511d2..5acd860 100644 (file)
--- a/src/view.cpp
+++ b/src/view.cpp
@@ -207,11 +207,24 @@ void View::Render(int width, int height)
        m_cached_display.Clear();
 
 #ifndef QUADTREE_DISABLED
+       // I'm going to write this out in comments, so hopefully then I'll understand it. :/
+       //
+       // This code looks at the current bounds and tries to work out how they need to change
+       // to keep the view looking at the correct quadtree node.
+       //
+       // The idea is that the width/height of the view bounds are always 0.5<=wh<=1.0. We then always
+       // try to keep the bottom-right corner of the node on-screen, changing nodes to suit. Why bottom-right,
+       // you may ask. It's an excellent question, with a dubious, hand-wavey answer: because we're manipulating
+       // the bounds, it was easier to do it that way. (The top-left corner of the bounds are within the main
+       // quadtree node).
        if (m_bounds_dirty || !m_lazy_rendering)
        {
+               // If we're too far zoomed out, become the parent of the current node.
                if ( m_bounds.w > 1.0 || m_bounds.h > 1.0)
                {
-                       //TODO: Generate a new parent node.
+                       // If a parent node exists, we'll become it.
+                       //TODO: Generate a new parent node if none exists, and work out when to change child_type
+                       // away from QTC_UNKNOWN
                        if (m_document.GetQuadTree().nodes[m_current_quadtree_node].parent != QUADTREE_EMPTY)
                        {
                                m_bounds = TransformFromQuadChild(m_bounds, m_document.GetQuadTree().nodes[m_current_quadtree_node].child_type);
@@ -219,31 +232,34 @@ void View::Render(int width, int height)
                        }
                }
 
-               // TODO: Support generating new parent nodes.
-               if (false && m_document.GetQuadTree().nodes[m_current_quadtree_node].parent != QUADTREE_EMPTY)
+               // If we have a parent... (This prevents some crashes, but should disappear.)
+               if (m_document.GetQuadTree().nodes[m_current_quadtree_node].parent != QUADTREE_EMPTY)
                {
-                       if (m_bounds.x < -0.5)
-                       {
-                               m_bounds = Rect(m_bounds.x + 1, m_bounds.y, m_bounds.w, m_bounds.h);
-                               m_current_quadtree_node = m_document.GetQuadTree().GetNeighbour(m_current_quadtree_node, -1, 0, &m_document);
-                       }
-                       if (m_bounds.y < -0.5)
-                       {
-                               m_bounds = Rect(m_bounds.x, m_bounds.y + 1, m_bounds.w, m_bounds.h);
-                               m_current_quadtree_node = m_document.GetQuadTree().GetNeighbour(m_current_quadtree_node, 0, -1, &m_document);
-                       }
-                       if (m_bounds.w + m_bounds.x > 0.5)
+                       // If the current node is off the left-hand side of the screen...
+                       while (m_bounds.x > 1)
                        {
+                               //... the current node becomes the node to its right.
                                m_bounds = Rect(m_bounds.x - 1, m_bounds.y, m_bounds.w, m_bounds.h);
                                m_current_quadtree_node = m_document.GetQuadTree().GetNeighbour(m_current_quadtree_node, 1, 0, &m_document);
                        }
-                       if (m_bounds.h + m_bounds.y > 0.5)
+                       while (m_bounds.y > 1)
                        {
                                m_bounds = Rect(m_bounds.x, m_bounds.y - 1, m_bounds.w, m_bounds.h);
                                m_current_quadtree_node = m_document.GetQuadTree().GetNeighbour(m_current_quadtree_node, 0, 1, &m_document);
                        }
+                       while (m_bounds.x < 0)
+                       {
+                               m_bounds = Rect(m_bounds.x + 1, m_bounds.y, m_bounds.w, m_bounds.h);
+                               m_current_quadtree_node = m_document.GetQuadTree().GetNeighbour(m_current_quadtree_node, -1, 0, &m_document);
+                       }
+                       while (m_bounds.y < 0)
+                       {
+                               m_bounds = Rect(m_bounds.x, m_bounds.y + 1, m_bounds.w, m_bounds.h);
+                               m_current_quadtree_node = m_document.GetQuadTree().GetNeighbour(m_current_quadtree_node, 0, -1, &m_document);
+                       }
                }
 
+               // Recurse into a node if we are completely within it. (If we're okay with having an invalid frame or two, we can remove this.)
                if (ContainedInQuadChild(m_bounds, QTC_TOP_LEFT))
                {
                        if (m_document.GetQuadTree().nodes[m_current_quadtree_node].top_left == QUADTREE_EMPTY)
@@ -288,6 +304,20 @@ void View::Render(int width, int height)
                        m_bounds = TransformToQuadChild(m_bounds, QTC_BOTTOM_RIGHT);
                        m_current_quadtree_node = m_document.GetQuadTree().nodes[m_current_quadtree_node].bottom_right;
                }
+
+               // Otherwise, we'll arbitrarily select the bottom-right.
+               // TODO: Perhaps select based on greatest area?
+               if (m_bounds.w < 0.5 || m_bounds.h < 0.5)
+               {
+                       if (m_document.GetQuadTree().nodes[m_current_quadtree_node].bottom_right == QUADTREE_EMPTY)
+                       {
+                               // We want to reparent into a child node, but none exist. Get the document to create one.
+                               m_document.GenQuadChild(m_current_quadtree_node, QTC_BOTTOM_RIGHT);
+                               m_render_dirty = true;
+                       }
+                       m_bounds = TransformToQuadChild(m_bounds, QTC_BOTTOM_RIGHT);
+                       m_current_quadtree_node = m_document.GetQuadTree().nodes[m_current_quadtree_node].bottom_right;
+               }
        }
 
        m_screen.DebugFontPrintF("Current View QuadTree");
@@ -299,6 +329,12 @@ void View::Render(int width, int height)
                overlay = m_document.GetQuadTree().nodes[overlay].next_overlay;
        }
        m_screen.DebugFontPrintF("\n");
+       m_screen.DebugFontPrintF("Left: %d, Right: %d, Up: %d, Down: %d\n",
+                       m_document.GetQuadTree().GetNeighbour(m_current_quadtree_node, -1, 0, 0),
+                       m_document.GetQuadTree().GetNeighbour(m_current_quadtree_node, 1, 0, 0),
+                       m_document.GetQuadTree().GetNeighbour(m_current_quadtree_node, 0, -1, 0),
+                       m_document.GetQuadTree().GetNeighbour(m_current_quadtree_node, 0, 1, 0));
+
 
        Rect view_top_bounds = m_bounds;
        QuadTreeIndex tmp = m_current_quadtree_node;
@@ -355,6 +391,7 @@ void View::RenderQuadtreeNode(int width, int height, QuadTreeIndex node, int rem
        if (!remaining_depth) return;
        //Debug("Rendering QT node %d, (objs: %d -- %d)\n", node, m_document.GetQuadTree().nodes[node].object_begin, m_document.GetQuadTree().nodes[node].object_end);
        m_bounds_dirty = true;
+       m_render_dirty = m_buffer_dirty = true;
        QuadTreeIndex overlay = node;
        while(overlay != -1)
        {
@@ -362,62 +399,27 @@ void View::RenderQuadtreeNode(int width, int height, QuadTreeIndex node, int rem
                overlay = m_document.GetQuadTree().nodes[overlay].next_overlay;
        }
 
-       if (m_bounds.Intersects(Rect(-1,-1,1,1)))
+       if (m_bounds.Intersects(Rect(1,1,1,1)))
        {
                m_bounds = Rect(m_bounds.x - 1, m_bounds.y - 1, m_bounds.w, m_bounds.h);
                m_bounds_dirty = true;
-               RenderQuadtreeNode(width, height, m_document.GetQuadTree().GetNeighbour(node, -1, -1, &m_document), remaining_depth - 1);
+               RenderQuadtreeNode(width, height, m_document.GetQuadTree().GetNeighbour(node, 1, 1, &m_document), remaining_depth - 1);
        }
        m_bounds = old_bounds;
-       if (m_bounds.Intersects(Rect(-1,0,1,1)))
+       if (m_bounds.Intersects(Rect(1,0,1,1)))
        {
                m_bounds = Rect(m_bounds.x - 1, m_bounds.y, m_bounds.w, m_bounds.h);
                m_bounds_dirty = true;
-               RenderQuadtreeNode(width, height, m_document.GetQuadTree().GetNeighbour(node, -1, 0, &m_document), remaining_depth - 1);
-       }
-       m_bounds = old_bounds;
-       if (m_bounds.Intersects(Rect(-1,1,1,1)))
-       {
-               m_bounds = Rect(m_bounds.x - 1, m_bounds.y + 1, m_bounds.w, m_bounds.h);
-               m_bounds_dirty = true;
-               RenderQuadtreeNode(width, height, m_document.GetQuadTree().GetNeighbour(node, -1, 1, &m_document), remaining_depth - 1);
-       }
-       m_bounds = old_bounds;
-       if (m_bounds.Intersects(Rect(0,-1,1,1)))
-       {
-               m_bounds = Rect(m_bounds.x, m_bounds.y - 1, m_bounds.w, m_bounds.h);
-               m_bounds_dirty = true;
-               RenderQuadtreeNode(width, height, m_document.GetQuadTree().GetNeighbour(node, 0, -1, &m_document), remaining_depth - 1);
+               RenderQuadtreeNode(width, height, m_document.GetQuadTree().GetNeighbour(node, 1, 0, &m_document), remaining_depth - 1);
        }
        m_bounds = old_bounds;
        if (m_bounds.Intersects(Rect(0,1,1,1)))
        {
-               m_bounds = Rect(m_bounds.x, m_bounds.y + 1, m_bounds.w, m_bounds.h);
+               m_bounds = Rect(m_bounds.x, m_bounds.y - 1, m_bounds.w, m_bounds.h);
                m_bounds_dirty = true;
                RenderQuadtreeNode(width, height, m_document.GetQuadTree().GetNeighbour(node, 0, 1, &m_document), remaining_depth - 1);
        }
        m_bounds = old_bounds;
-       if (m_bounds.Intersects(Rect(1,-1,1,1)))
-       {
-               m_bounds = Rect(m_bounds.x + 1, m_bounds.y - 1, m_bounds.w, m_bounds.h);
-               m_bounds_dirty = true;
-               RenderQuadtreeNode(width, height, m_document.GetQuadTree().GetNeighbour(node, 1, -1, &m_document), remaining_depth - 1);
-       }
-       m_bounds = old_bounds;
-       if (m_bounds.Intersects(Rect(1,0,1,1)))
-       {
-               m_bounds = Rect(m_bounds.x + 1, m_bounds.y, m_bounds.w, m_bounds.h);
-               m_bounds_dirty = true;
-               RenderQuadtreeNode(width, height, m_document.GetQuadTree().GetNeighbour(node, 1, 0, &m_document), remaining_depth - 1);
-       }
-       m_bounds = old_bounds;
-       if (m_bounds.Intersects(Rect(1,1,1,1)))
-       {
-               m_bounds = Rect(m_bounds.x + 1, m_bounds.y + 1, m_bounds.w, m_bounds.h);
-               m_bounds_dirty = true;
-               RenderQuadtreeNode(width, height, m_document.GetQuadTree().GetNeighbour(node, 1, 1, &m_document), remaining_depth - 1);
-       }
-       m_bounds = old_bounds;
        m_bounds_dirty = true;
 
 #if 0