From e9212bf1b65c573a2de6d49679d03dae09cd6e42 Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Thu, 9 Jul 2009 22:03:29 +0100
Subject: [PATCH] Automatically make fog same colour as clear

---
 include/IFog.hpp     | 3 +++
 src/Fog.cpp          | 9 +++++++++
 src/Map.cpp          | 5 +----
 src/OpenGLHelper.cpp | 3 +++
 4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/include/IFog.hpp b/include/IFog.hpp
index 0edfecd..ca73d35 100644
--- a/include/IFog.hpp
+++ b/include/IFog.hpp
@@ -33,4 +33,7 @@ typedef std::tr1::shared_ptr<IFog> IFogPtr;
 IFogPtr makeFog(float r, float g, float b,
                 float density, float start, float end);
 
+// Construct a fog from the current clear colour
+IFogPtr makeFog(float density, float start, float end);
+
 #endif
diff --git a/src/Fog.cpp b/src/Fog.cpp
index acb12f1..c3ad9d0 100644
--- a/src/Fog.cpp
+++ b/src/Fog.cpp
@@ -55,4 +55,13 @@ IFogPtr makeFog(float r, float g, float b,
    return IFogPtr(new Fog(r, g, b, density, start, end));
 }
 
+IFogPtr makeFog(float density, float start, float end)
+{
+   float params[4];
+   glGetFloatv(GL_COLOR_CLEAR_VALUE, params);
+   
+   return makeFog(params[0], params[1], params[2],
+                  density, start, end);
+}
+
 #endif
diff --git a/src/Map.cpp b/src/Map.cpp
index 773e564..3f89239 100644
--- a/src/Map.cpp
+++ b/src/Map.cpp
@@ -204,8 +204,7 @@ Map::Map()
      myStartDirection(axis::X),
      shouldDrawGridLines(false), inPickMode(false)
 {
-   myFog = makeFog(0.6f, 0.7f, 0.8f,  // Colour
-                   0.25f,             // Density
+   myFog = makeFog(0.25f,             // Density
                    60.0f, 70.0f);     // Start and end distance
 }
 
@@ -382,8 +381,6 @@ void Map::render(IGraphicsPtr aContext) const
 {
    resetMarks();
    
-   glClearColor(0.6f, 0.7f, 0.8f, 1.0f);
-   
    myFog->apply();
    
    glPushAttrib(GL_ALL_ATTRIB_BITS);
diff --git a/src/OpenGLHelper.cpp b/src/OpenGLHelper.cpp
index d8b9b46..c207ad9 100644
--- a/src/OpenGLHelper.cpp
+++ b/src/OpenGLHelper.cpp
@@ -101,6 +101,9 @@ void initGL()
    glDepthFunc(GL_LEQUAL);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
+   // Clear to the sky colour
+   glClearColor(0.6f, 0.7f, 0.8f, 1.0f);
+   
    // Check for OpenGL extensions   
    GLenum err = glewInit();
    if (err != GLEW_OK)
-- 
2.39.2