BansheeEngine/Data/Raw/Engine/Includes/NormalVertexInput.bslinc

Technique
#ifdef USE_BLEND_SHAPES
	 : base("MorphVertexInput") =
#else
	 : base("NormalVertexInput") =
#endif
{
	Pass =
	{
		Common = 
		{
			struct VStoFS
			{
				float4 position : SV_Position;
				float2 uv0 : TEXCOORD0;
				float3 worldPosition : TEXCOORD1;
				
				float3 tangentToWorldZ : NORMAL; // Note: Half-precision could be used
				float4 tangentToWorldX : TANGENT; // Note: Half-precision could be used
			};
		};

		Vertex =
		{
			struct VertexInput
			{
				float3 position : POSITION;
				float3 normal : NORMAL; // Note: Half-precision could be used
				float4 tangent : TANGENT; // Note: Half-precision could be used
				float2 uv0 : TEXCOORD0;
				
				#ifdef USE_BLEND_SHAPES
					float3 deltaPosition : POSITION1;
					float4 deltaNormal : NORMAL1;
				#endif				
			};
			
			struct VertexIntermediate
			{
				float3 worldNormal; // Note: Half-precision could be used
				float4 worldTangent; // Note: Half-precision could be used
				
				float tangentSign;
			};
			
			float3x3 getTangentToLocal(VertexInput input, out float tangentSign)
			{
				float3 normal = input.normal * 2.0f - 1.0f;
				float3 tangent = input.tangent.xyz * 2.0f - 1.0f;
				
				#ifdef USE_BLEND_SHAPES
					float3 deltaNormal = (input.deltaNormal.xyz * 2.0f - 1.0f) * 2.0f;
					normal = normalize(normal + deltaNormal * input.deltaNormal.w);
					tangent = normalize(tangent - dot(tangent, normal) * normal);
				#endif
				
				float3 bitangent = cross(normal, tangent) * input.tangent.w;
				tangentSign = input.tangent.w * gWorldDeterminantSign;
				
				// Note: Maybe it's better to store everything in row vector format?
				float3x3 result = float3x3(tangent, bitangent, normal);
				result = transpose(result);
												
				return result;
			}
			
			VertexIntermediate getVertexIntermediate(VertexInput input)
			{
				VertexIntermediate result;
				
				float tangentSign;
				float3x3 tangentToLocal = getTangentToLocal(input, tangentSign);
				float3x3 tangentToWorld = mul((float3x3)gMatWorldNoScale, tangentToLocal);
				
				// Note: Consider transposing these externally, for easier reads
				result.worldNormal = float3(tangentToWorld[0][2], tangentToWorld[1][2], tangentToWorld[2][2]); // Normal basis vector
				result.worldTangent = float4(tangentToWorld[0][0], tangentToWorld[1][0], tangentToWorld[2][0], tangentSign); // Tangent basis vector
				
				return result;
			}
			
			float4 getVertexWorldPosition(VertexInput input, VertexIntermediate intermediate)
			{
				#ifdef USE_BLEND_SHAPES
					float4 position = float4(input.position + input.deltaPosition, 1.0f);
				#else
					float4 position = float4(input.position, 1.0f);
				#endif			
			
				return mul(gMatWorld, position);
			}
			
			void populateVertexOutput(VertexInput input, VertexIntermediate intermediate, inout VStoFS result)
			{
				result.uv0 = input.uv0;
				
				result.tangentToWorldZ = intermediate.worldNormal;
				result.tangentToWorldX = intermediate.worldTangent;
			}
		};
	};
};