improve lighting calculations

Author: mlavik1

Assets/Shaders/DirectVolumeRenderingShader.shader

@@ -47,7 +47,7 @@
             #include "UnityCG.cginc"
             #include "Include/TricubicSampling.cginc"
 
-            #define AMBIENT_LIGHTING_FACTOR 0.5
+            #define AMBIENT_LIGHTING_FACTOR 0.2
             #define JITTER_FACTOR 5.0
 
             struct vert_in
@@ -252,13 +252,15 @@
                 // Optimised version of: if(dot(normal, eyeDir) < 0.0) normal *= -1.0
                 normal *= (step(0.0, dot(normal, eyeDir)) * 2.0 - 1.0);
 
-                float ndotl = max(lerp(0.0f, 1.5f, dot(normal, lightDir)), AMBIENT_LIGHTING_FACTOR);
+                float ndotl = max(dot(normal, lightDir), 0.0f);
                 float3 diffuse = ndotl * col;
+                float3 ambient = AMBIENT_LIGHTING_FACTOR * col;
                 float3 v = eyeDir;
                 float3 r = normalize(reflect(-lightDir, normal));
                 float rdotv = max( dot( r, v ), 0.0 );
                 float3 specular = pow(rdotv, 32.0f) * float3(1.0f, 1.0f, 1.0f) * specularIntensity;
-                return diffuse + specular;
+                float3 result = diffuse + ambient + specular;
+                return float3(min(result.r, 1.0f), min(result.g, 1.0f), min(result.b, 1.0f));
             }
 
             float calculateShadow(float3 pos, float3 lightDir)
@@ -355,6 +357,7 @@
 #if defined(TF2D_ON) || defined(LIGHTING_ON)
                     float3 gradient = getGradient(currPos);
                     float gradMag = length(gradient);
+
                     float gradMagNorm = gradMag / 1.75f;
 #endif