Completed Metal implementation

res/shaders/Common.slang

@@ -10,20 +10,23 @@ struct Camera
     float ks;
     float A;
     float ka;
+    float2 sensorSize;
+    uint width;
+    uint height;
 };
 
 struct MaterialParameter
 {
-    float3 albedo = float3(1, 1, 1);
-    float alpha = 1;
-    float3 specularColor = float3(1, 1, 1);
-    float shininess = 0.04;
-    float3 emissive = float3(0, 0, 0);
+    float4 albedo_alpha;      // xyz: albedo, w: alpha
+    float4 specularColor_sh; // xyz: specularColor, w: shininess
+    float4 emissive_type;     // xyz: emissive, w: materialType (as float)
     float3 shade(float3 normal, float3 viewDir, float3 lightDir, float3 lightColor)
     {
+        float3 albedo = albedo_alpha.xyz;
+        float shininess = specularColor_sh.w;
         float diffuse = max(dot(normal, lightDir), 0);
         float3 h = normalize(lightDir + viewDir);
-        float specular = pow(clamp(dot(normal, h), 0, 1), shininess);
+        float specular = pow(clamp(dot(normal, h), 0.0f, 1.0f), shininess);
 
         return (albedo * diffuse * lightColor);
     }
@@ -34,6 +37,7 @@ struct ModelReference
   uint32_t positionOffset = 0;
   uint32_t indicesOffset = 0;
   uint32_t numIndices = 0;
+  uint32_t materialIndex = 0;
 };
 
 struct PointLight