From 100ee0eec106beacbf356cc691094171b5650596 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C3=ABl=20Lemaire?= <michael@thunderk.net>
Date: Wed, 19 Aug 2015 17:22:14 +0200
Subject: [PATCH] Fixed underwater terrain detection in opengl renderer

---
 src/render/opengl/ExplorerChunkTerrain.cpp | 46 +++++++++++++++++-----
 src/render/opengl/ExplorerChunkTerrain.h   |  4 +-
 2 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/src/render/opengl/ExplorerChunkTerrain.cpp b/src/render/opengl/ExplorerChunkTerrain.cpp
index 4100ee2..a423237 100644
--- a/src/render/opengl/ExplorerChunkTerrain.cpp
+++ b/src/render/opengl/ExplorerChunkTerrain.cpp
@@ -8,6 +8,8 @@
 #include "OpenGLRenderer.h"
 #include "TerrainRenderer.h"
 #include "VertexArray.h"
+#include "Scenery.h"
+#include "TerrainDefinition.h"
 
 ExplorerChunkTerrain::ExplorerChunkTerrain(OpenGLRenderer* renderer, double x, double z, double size, int nbchunks):
     _renderer(renderer)
@@ -31,8 +33,9 @@ ExplorerChunkTerrain::ExplorerChunkTerrain(OpenGLRenderer* renderer, double x, d
     _overall_step = size * (double) nbchunks;
 
     distance_to_camera = 0.0;
-
-    overwater = false;
+    underwater = false;
+    lowest = 0.0;
+    highest = 0.0;
 
     tessellation_count = 33;
     tessellated = new VertexArray<TerrainVertex>();
@@ -62,15 +65,23 @@ bool ExplorerChunkTerrain::maintain()
     {
         _reset_topology = false;
         _tessellation_current_size = 0;
-        overwater = false;
+        lowest = 10000.0;
+        highest = -10000.0;
+        underwater = false;
     }
     if (_reset_texture)
     {
         _reset_texture = false;
         _texture_current_size = 0;
+        underwater = false;
     }
     _lock_data.unlock();
 
+    if (underwater)
+    {
+        return false;
+    }
+
     // Improve heightmap resolution
     if (_tessellation_current_size < _tessellation_max_size)
     {
@@ -90,9 +101,13 @@ bool ExplorerChunkTerrain::maintain()
                         double z = _startz + _tessellation_step * (float)j;
 
                         double height = _renderer->getTerrainRenderer()->getHeight(x, z, true, false);
-                        if (height >= 0.0)
+                        if (height >= highest)
                         {
-                            overwater = true;
+                            highest = height;
+                        }
+                        if (height <= lowest)
+                        {
+                            lowest = height;
                         }
 
                         TerrainVertex v;
@@ -113,6 +128,8 @@ bool ExplorerChunkTerrain::maintain()
                 }
             }
 
+            underwater = highest < -_renderer->getScenery()->getTerrain()->getWaterOffset();
+
             _lock_data.lock();
             _tessellation_current_size = new_tessellation_size;
             tessellated->setAutoGridIndices(tessellation_count, new_tessellation_inc);
@@ -170,6 +187,14 @@ bool ExplorerChunkTerrain::maintain()
 
 void ExplorerChunkTerrain::updatePriority(CameraDefinition* camera)
 {
+    // Under water check
+    underwater = highest < -_renderer->getScenery()->getTerrain()->getWaterOffset();
+    if (underwater)
+    {
+        priority = -10000.0;
+        return;
+    }
+
     Vector3 camera_location = camera->getLocation();
 
     // Handle position
@@ -198,11 +223,7 @@ void ExplorerChunkTerrain::updatePriority(CameraDefinition* camera)
     _lock_data.unlock();
 
     // Update wanted LOD
-    if (not overwater)
-    {
-        _texture_wanted_size = 2;
-    }
-    else if (distance_to_camera < 60.0)
+    if (distance_to_camera < 60.0)
     {
         _texture_wanted_size = _texture_max_size;
     }
@@ -237,6 +258,11 @@ void ExplorerChunkTerrain::updatePriority(CameraDefinition* camera)
 
 void ExplorerChunkTerrain::render(QOpenGLShaderProgram* program, OpenGLFunctions* functions)
 {
+    if (underwater)
+    {
+        return;
+    }
+
     // Put texture in place
     _lock_data.lock();
     if (_texture_changed)
diff --git a/src/render/opengl/ExplorerChunkTerrain.h b/src/render/opengl/ExplorerChunkTerrain.h
index d6852a4..60dcdf3 100644
--- a/src/render/opengl/ExplorerChunkTerrain.h
+++ b/src/render/opengl/ExplorerChunkTerrain.h
@@ -65,8 +65,10 @@ private:
     int _texture_max_size;
 
     // LOD control
+    bool underwater;
+    double lowest;
+    double highest;
     double distance_to_camera;
-    bool overwater;
 };
 
 }