Implemented specular reflective lighting for OpenGL 3.x, everything looks shiny (will add APIs to make it less shiny ;-)

Remove roof from kitchens/1.sdf, otherwise shadows and shinyness won't work (light is outside the room, bouncing against roof-top)
Make kuka_iiwa/model.urdf more smooth, use .obj for per-vertex normals (using Blender, import STL, export OBJ, enable triangles, normals and Z-UP, Y forward)

examples/OpenGLWindow/Shaders/useShadowMapInstancingPS.glsl

@@ -13,9 +13,14 @@ in Vert
 
 uniform sampler2D Diffuse;
 uniform sampler2DShadow shadowMap;
+uniform mat4 ViewMatrixInverse;
 
-in vec3 lightDir,normal,ambient;
+in vec3 lightPos,cameraPosition, normal,ambient;
 in vec4 ShadowCoord;
+in vec4 vertexPos;
+in float materialShininess;
+in vec3 lightSpecularIntensity;
+in vec3 materialSpecularColor;
 
 out vec4 color;
 
@@ -28,8 +33,11 @@ void main(void)
 	float intensity,at,af;
 	if (fragment.color.w==0)
 		discard;
-
-	intensity = 0.5+0.5*clamp( dot( normalize(normal),lightDir ), -1,1 );
+	vec3 lightDir = normalize(lightPos);
+	
+	vec3 normalDir = normalize(normal);
+ 
+	intensity = 0.5+0.5*clamp( dot( normalDir,lightDir ), -1,1 );
 	
 	af = 1.0;
 		
@@ -38,7 +46,24 @@ void main(void)
 		
 	//float bias = 0.005f;
 	
+	vec3 specularReflection;
 	
+	if (dot(normalDir, lightDir) < 0.0) 
+	{
+		specularReflection = vec3(0.0, 0.0, 0.0);
+	}
+  else // light source on the right side
+	{
+		vec3 surfaceToLight = normalize(lightPos - vertexPos.xyz);
+    vec3 surfaceToCamera = normalize(cameraPosition - vertexPos.xyz);
+    
+    
+    float specularCoefficient = 0.0;
+		specularCoefficient = pow(max(0.0, dot(surfaceToCamera, reflect(-surfaceToLight, normalDir))), materialShininess);
+    specularReflection = specularCoefficient * materialSpecularColor * lightSpecularIntensity;
+  
+	}
+    
 
 	float visibility = texture(shadowMap, vec3(ShadowCoord.xy,(ShadowCoord.z)/ShadowCoord.w));
 	if (intensity<0.5)
@@ -46,6 +71,6 @@ void main(void)
 
 	intensity = 0.7*intensity  + 0.3*intensity*visibility;
 	
-	cf = intensity*(vec3(1.0,1.0,1.0)-ambient)+ambient;
+	cf = intensity*(vec3(1.0,1.0,1.0)-ambient)+ambient+specularReflection*visibility;
 	color  = vec4(ct * cf, fragment.color.w);
 }