Order drawlist by distance to the camera when rendering (#11651)

1 files changed, 29 insertions, 1 deletions

diff --git a/src/client/clientmap.h b/src/client/clientmap.h
index 97ce8d355..b4dc42395 100644
--- a/src/client/clientmap.h
+++ b/src/client/clientmap.h
@@ -87,10 +87,18 @@ public:
 
 	void updateCamera(const v3f &pos, const v3f &dir, f32 fov, const v3s16 &offset)
 	{
+		v3s16 previous_block = getContainerPos(floatToInt(m_camera_position, BS) + m_camera_offset, MAP_BLOCKSIZE);
+
 		m_camera_position = pos;
 		m_camera_direction = dir;
 		m_camera_fov = fov;
 		m_camera_offset = offset;
+
+		v3s16 current_block = getContainerPos(floatToInt(m_camera_position, BS) + m_camera_offset, MAP_BLOCKSIZE);
+
+		// reorder the blocks when camera crosses block boundary
+		if (previous_block != current_block)
+			m_needs_update_drawlist = true;
 	}
 
 	/*
@@ -122,6 +130,8 @@ public:
 		v3s16 *p_blocks_min, v3s16 *p_blocks_max, float range=-1.0f);
 	void updateDrawList();
 	void updateDrawListShadow(const v3f &shadow_light_pos, const v3f &shadow_light_dir, float shadow_range);
+	// Returns true if draw list needs updating before drawing the next frame.
+	bool needsUpdateDrawList() { return m_needs_update_drawlist; }
 	void renderMap(video::IVideoDriver* driver, s32 pass);
 
 	void renderMapShadows(video::IVideoDriver *driver,
@@ -140,6 +150,23 @@ public:
 	f32 getCameraFov() const { return m_camera_fov; }
 
 private:
+	// Orders blocks by distance to the camera
+	class MapBlockComparer
+	{
+	public:
+		MapBlockComparer(const v3s16 &camera_block) : m_camera_block(camera_block) {}
+
+		bool operator() (const v3s16 &left, const v3s16 &right) const
+		{
+			auto distance_left = left.getDistanceFromSQ(m_camera_block);
+			auto distance_right = right.getDistanceFromSQ(m_camera_block);
+			return distance_left > distance_right || (distance_left == distance_right && left > right);
+		}
+
+	private:
+		v3s16 m_camera_block;
+	};
+
 	Client *m_client;
 	RenderingEngine *m_rendering_engine;
 
@@ -153,8 +180,9 @@ private:
 	f32 m_camera_fov = M_PI;
 	v3s16 m_camera_offset;
 
-	std::map<v3s16, MapBlock*> m_drawlist;
+	std::map<v3s16, MapBlock*, MapBlockComparer> m_drawlist;
 	std::map<v3s16, MapBlock*> m_drawlist_shadow;
+	bool m_needs_update_drawlist;
 
 	std::set<v2s16> m_last_drawn_sectors;