From 3e440fd88d58bd91f50e1a6e9e3cb3c991a0e7c8 Mon Sep 17 00:00:00 2001
From: auria <auria@178a84e3-b1eb-0310-8ba1-8eac791a3b58>
Date: Sat, 3 Dec 2011 20:09:08 +0000
Subject: [PATCH] Improve how normal maps work on movimng objects

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@10312 178a84e3-b1eb-0310-8ba1-8eac791a3b58
---
 data/shaders/normalmap.frag | 5 ++++-
 data/shaders/splatting.frag | 6 +++++-
 src/graphics/material.cpp   | 7 ++++++-
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/data/shaders/normalmap.frag b/data/shaders/normalmap.frag
index 6628f77f3..87881d505 100644
--- a/data/shaders/normalmap.frag
+++ b/data/shaders/normalmap.frag
@@ -8,6 +8,9 @@ uniform sampler2D BumpTex; //The bump-map
  varying vec3 LightDir; //Receiving the transformed light direction 
  void main() 
  {
+   vec4 LightDirTransformed4 = gl_ProjectionMatrix * gl_ModelViewMatrix * vec4(LightDir[0], LightDir[1], LightDir[2], 0);
+   vec3 LightDirTransformed = vec3(LightDirTransformed4[0], LightDirTransformed4[1], LightDirTransformed4[2]);
+   
    //Get the color of the bump-map
    vec3 BumpNorm = vec3(texture2D(BumpTex, gl_TexCoord[0].xy));
    //Get the color of the texture
@@ -15,7 +18,7 @@ uniform sampler2D BumpTex; //The bump-map
    //Expand the bump-map into a normalized signed vector
    BumpNorm = (BumpNorm -0.5) * 2.0;
    //Find the dot product between the light direction and the normal
-   float NdotL = max(dot(BumpNorm, LightDir), 0.0) / 3.0 * 2.1 + 0.5;
+   float NdotL = max(dot(BumpNorm, LightDirTransformed), 0.0) / 3.0 * 2.1 + 0.5;
    //Calculate the final color gl_FragColor
    vec3 diffuse = NdotL * passcolor.xyz * DecalCol;
    //Set the color of the fragment...  If you want specular lighting or other types add it here
diff --git a/data/shaders/splatting.frag b/data/shaders/splatting.frag
index a080313b2..fcc5e6ce1 100644
--- a/data/shaders/splatting.frag
+++ b/data/shaders/splatting.frag
@@ -5,6 +5,7 @@ uniform sampler2D tex_detail0;
 uniform sampler2D tex_detail1;
 uniform sampler2D tex_detail2;
 uniform sampler2D tex_detail3;
+uniform sampler2D tex_detail4;
 
 void main()
 {
@@ -13,8 +14,11 @@ void main()
     vec4 detail1 = texture2D(tex_detail1, gl_TexCoord[1].st);
     vec4 detail2 = texture2D(tex_detail2, gl_TexCoord[1].st);
     vec4 detail3 = texture2D(tex_detail3, gl_TexCoord[1].st);
+    vec4 detail4 = texture2D(tex_detail4, gl_TexCoord[1].st);
+
     gl_FragColor = layout.r * detail0 +
                    layout.g * detail1 +
                    layout.b * detail2 +
-                   (1.0 - layout.r - layout.g - layout.b) * detail3;
+                   (1.0 - layout.r - layout.g - layout.b) * detail3 +
+                   (1.0 - layout.a) * detail4;
 }
diff --git a/src/graphics/material.cpp b/src/graphics/material.cpp
index 14f93f5df..98a1f8b7c 100644
--- a/src/graphics/material.cpp
+++ b/src/graphics/material.cpp
@@ -60,7 +60,12 @@ public:
         services->setPixelShaderConstant("BumpTex", (float*)&bumptex, 1);
         
         // TODO: check the position of the sun
-        const float lightdir[] = {0.5f, 0.5f, 1.0f};
+        /*
+         You have to calculate the light position in (model)view Space. It can be done, by transforming the light positions and rotations
+         with the modelviewmatrix, after the camera is set. You should do this calculations before the shader runs, but it is also possible
+         to pass the camera matrix (calculation in modelviewspace) or ModelMatrix (calculation in WorldSpace) to a shader. 
+         */
+        const float lightdir[] = {-0.5f, -0.5f, -1.0f};
         services->setVertexShaderConstant("lightdir", lightdir, 3);
     }
 };