Add the final touch for the dirt shader

data/shaders/sp_kart_dirt.frag

@@ -13,14 +13,15 @@ layout(location = 1) out vec4 o_normal_color;
 #stk_include "utils/rgb_conversion.frag"
 #stk_include "utils/sp_texture_sampling.frag"
 
-uniform sampler2D g_kart_dirt;
+uniform sampler2D g_dirt_albedo;
+uniform sampler2D g_dirt_normal;
 uniform float dirt_factor;
 
 void main()
 {
     // Triplanar detail map
     vec2 xyuv = vec2(world_position.x, world_position.y);
-    vec3 dirt = texture(g_kart_dirt, uv * 32).rgb;
+    vec3 dirt = texture(g_dirt_albedo, uv * 4).rgb;
 
     vec4 col = sampleTextureLayer0(uv);
     if (hue_change > 0.0)
@@ -41,19 +42,28 @@ void main()
     }
 
     float dirtMask = sampleTextureLayer4(uv).r;
-    dirtMask *= dirtMask;
+    float nitroMask = sampleTextureLayer4(uv).g;
+    //dirtMask *= dirtMask;
     // Dirt factor
     dirtMask = 1.0 - dirtMask;
-    dirtMask *= dirt_factor;
+    dirtMask *= clamp(dirt_factor, 0.0, 1.0);
+    nitroMask *= clamp(dirt_factor, 0.0, 1.0);
     vec3 final_color = col.xyz * color.xyz;
     final_color = mix(final_color, dirt, dirtMask);
 
+    final_color = mix(final_color, vec3(0, 0.415, 0.639), nitroMask); 
+
 #if defined(Advanced_Lighting_Enabled)
     vec4 layer_2 = sampleTextureLayer2(uv);
     vec4 layer_3 = sampleTextureLayer3(uv);
+    // Part emitting light
+    layer_2.z = mix(layer_2.z, 1.0, nitroMask);
     o_diffuse_color = vec4(final_color, layer_2.z);
     // Dirt part should not be glossy
     layer_2.r = mix(layer_2.r, 0.0, dirtMask);
+    // Mix the normal map for the dirt
+    vec4 dirt_nor = texture(g_dirt_normal, uv * 4);
+    layer_3 = mix(layer_3, dirt_nor, dirtMask);
 
     vec3 tangent_space_normal = 2.0 * layer_3.xyz - 1.0;
     vec3 frag_tangent = normalize(tangent);

data/shaders/sps_14_kart.xml

@@ -4,8 +4,10 @@
         fragment-shader="sp_kart_dirt.frag"
         skinned-mesh-shader="sp_skinning.vert">
     <prefilled-textures>
-            <prefilled-texture name="g_kart_dirt" file="dirt.jpg"
+            <prefilled-texture name="g_dirt_albedo" file="gfx_kartDirt_a_Albedo.png"
                  srgb="Y" sampler="trilinear"/>
+            <prefilled-texture name="g_dirt_normal" file="gfx_kartDirt_a_Normal.png"
+                 sampler="trilinear"/>
     </prefilled-textures>
     </first-pass>
     <shadow-pass vertex-shader="sp_shadow.vert"

src/graphics/sp/sp_shader_manager.cpp

@@ -65,14 +65,16 @@ SPShaderManager::SPShaderManager()
         { "dirtFactorUniformAssigner", [](SPUniformAssigner* ua)
             {
                 AbstractKart* k = NULL;
-                if (Camera::getNumCameras() > 1)
+                if (Camera::getNumCameras() > 0)
                 {
-                    Camera* camera = Camera::getCamera(0);
-                    k = camera->getKart();
+                    if (Camera::getActiveCamera() != NULL)
+                    {
+                        k = Camera::getActiveCamera()->getKart();
+                    }
                 }
-                if (k && k->isOnGround())
+                if (k)
                 {
-                    ua->setValue(2.0f);
+                    ua->setValue(k->getDirtFactor());
                 }
                 else
                 {

src/karts/abstract_kart.hpp

@@ -356,6 +356,9 @@ public:
     /** True if the wheels are touching the ground. */
     virtual bool isOnGround() const = 0;
     // ------------------------------------------------------------------------
+    /** Returns the dirt factor (how dirty the kart is). */
+    virtual float getDirtFactor() const = 0;
+    // ------------------------------------------------------------------------
     /** Returns the slipstream object of this kart. */
     virtual const SlipStream* getSlipstream() const = 0;
     // ------------------------------------------------------------------------

src/karts/kart.cpp

@@ -377,6 +377,8 @@ void Kart::reset()
     m_view_blocked_by_plunger = 0;
     m_has_caught_nolok_bubblegum = false;
     m_is_jumping           = false;
+    m_dirt_factor          = 0.0f;
+    m_dirt_reset_counter   = 0.0f;
 
     for (int i=0;i<m_xyz_history_size;i++)
     {
@@ -1164,6 +1166,14 @@ bool Kart::isOnGround() const
           && !getKartAnimation());
 }   // isOnGround
 
+//-----------------------------------------------------------------------------
+/** The kart as a dirt factor (if the player skids and go in dirty places)
+ */
+ float Kart::getDirtFactor() const
+ {
+     return m_dirt_factor;
+ }   // getDirtFactor
+
 //-----------------------------------------------------------------------------
 /** The kart is near the ground, but not necessarily on it (small jumps). This
  *  is used to determine when to stop flying.
@@ -1890,6 +1900,29 @@ void Kart::handleMaterialGFX(float dt)
 {
     const Material *material = getMaterial();
 
+    if (m_skidding->isSkidding())
+    {
+        m_dirt_factor += 0.001f;
+        if (m_dirt_factor > 1.0f)
+        {
+            m_dirt_factor = 1.0f;
+        }
+        m_dirt_reset_counter = 2.0f;
+    }
+    else
+    {
+        m_dirt_reset_counter -= 0.01f;
+        if (m_dirt_reset_counter < 0.0f)
+        {
+            m_dirt_reset_counter = 0.0f;
+            m_dirt_factor -= 0.002f;
+            if (m_dirt_factor < 0.0f)
+            {
+                m_dirt_factor = 0.0f;
+            }
+        }
+    }
+
     // First test: give the terrain effect, if the kart is
     // on top of a surface (i.e. not falling), actually touching
     // something with the wheels, and the material has not the

src/karts/kart.hpp

@@ -166,6 +166,12 @@ protected:
      *  the kart is squashed. */
     float        m_squash_time;
 
+    /** How dirty the kart is, 0 = clean */
+    float        m_dirt_factor;
+
+    /** Counter to reset the dirt */
+    float        m_dirt_reset_counter;
+
     /** Current leaning of the kart. */
     float        m_current_lean;
 
@@ -453,6 +459,9 @@ public:
     /** True if the wheels are touching the ground. */
     virtual bool isOnGround() const OVERRIDE;
     // ------------------------------------------------------------------------
+    /** Returns the dirt factor (how dirty the kart is). */
+    virtual float getDirtFactor() const OVERRIDE;
+    // ------------------------------------------------------------------------
     /** Returns true if the kart is close to the ground, used to dis/enable
      *  the upright constraint to allow for more realistic explosions. */
     bool isNearGround() const;