Slightly reworked glTF samples

Parent matrices are now applied (where available)
Now more in line with the base code glTF loader
Refs #964

data/shaders/hlsl/gltfloading/mesh.frag

@@ -24,7 +24,7 @@ float4 main(VSOutput input) : SV_TARGET
 	float3 N = normalize(input.Normal);
 	float3 L = normalize(input.LightVec);
 	float3 V = normalize(input.ViewVec);
-	float3 R = reflect(-L, N);
+	float3 R = reflect(L, N);
 	float3 diffuse = max(dot(N, L), 0.0) * input.Color;
 	float3 specular = pow(max(dot(R, V), 0.0), 16.0) * float3(0.75, 0.75, 0.75);
 	return float4(diffuse * color.rgb + specular, 1.0);

data/shaders/hlsl/gltfloading/mesh.vert

@@ -13,6 +13,7 @@ struct UBO
 	float4x4 projection;
 	float4x4 view;
 	float4 lightPos;
+	float4 viewPos;
 };
 
 cbuffer ubo : register(b0) { UBO ubo; }
@@ -42,8 +43,7 @@ VSOutput main(VSInput input)
 
 	float4 pos = mul(ubo.view, float4(input.Pos, 1.0));
 	output.Normal = mul((float3x3)ubo.view, input.Normal);
-	float3 lPos = mul((float3x3)ubo.view, ubo.lightPos.xyz);
-	output.LightVec = lPos - pos.xyz;
-	output.ViewVec = -pos.xyz;
+	output.LightVec = ubo.lightPos.xyz - pos.xyz;
+	output.ViewVec = ubo.viewPos.xyz - pos.xyz;
 	return output;
 }