//Calculation taken from: https://learnopengl.com/Advanced-Lighting/Normal-Mapping
TangentSpaceData GetTangentSpaceData(List <Vector3> positions, List <Vector2> uvs)
{
if (positions.Count != uvs.Count)
{
throw new Exception("Position Data does not match the amount of uv data");
}
Vector3[] tangents = new Vector3[positions.Count];
Vector3[] biTangents = new Vector3[positions.Count];
for (int i = 0; i < positions.Count - 2; i += 2)
{
int idx1 = i;
int idx2 = i + 1;
int idx3 = i + 2;
Vector3 pos1 = positions[idx1];
Vector3 pos2 = positions[idx2];
Vector3 pos3 = positions[idx3];
Vector3 edge1 = pos2 - pos1;
Vector3 edge2 = pos3 - pos1;
Vector2 uv1 = uvs[idx1];
Vector2 uv2 = uvs[idx2];
Vector2 uv3 = uvs[idx3];
Vector2 deltaUV1 = uv2 - uv1;
Vector2 deltaUV2 = uv3 - uv1;
float f = 1.0f / (deltaUV1.Y * deltaUV2.X - deltaUV1.X * deltaUV2.Y);
Vector3 tangent;
tangent.X = f * (deltaUV2.Y * edge1.X - deltaUV1.Y * edge2.X);
tangent.Y = f * (deltaUV2.Y * edge1.Y - deltaUV1.Y * edge2.Y);
tangent.Z = f * (deltaUV2.Y * edge1.Z + deltaUV1.Y * edge2.Z);
tangent = Vector3.Normalize(tangent);
Vector3 biTangent;
biTangent.X = f * (-deltaUV2.X * edge1.X + deltaUV1.X * edge2.X);
biTangent.Y = f * (-deltaUV2.X * edge1.Y + deltaUV1.X * edge2.Y);
biTangent.Z = f * (-deltaUV2.X * edge1.Z + deltaUV1.X * edge2.Z);
biTangent = Vector3.Normalize(biTangent);
tangents[idx1] = tangent;
biTangents[idx1] = biTangent;
tangents[idx2] = tangent;
biTangents[idx2] = biTangent;
tangents[idx3] = tangent;
biTangents[idx3] = biTangent;
}
TangentSpaceData result = new TangentSpaceData();
result.tangent = tangents;
result.biTangent = biTangents;
return(result);
}
List <GameObject> GetSphereSampleScene()
{
List <GameObject> goList = new List <GameObject>();
DefaultMesh plane = Meshes.CreatePlane(10, 10, 10, 10).Transform(Transformation.Translation(new Vector3(0, -1f, 0)));
VAO planeMesh = VAOLoader.FromMesh(plane, renderer.GetPBRShader());
GameObject planeGO = new GameObject();
PBRMaterial planemat = new PBRMaterial();
planemat.albedoColor = new Vector3(1);
planemat.roughness = 1;
planemat.metal = 0;
planeGO.mesh = planeMesh;
planeGO.material = planemat;
//goList.Add(planeGO);
//return goList;
int gridSize = 7;
float sphereSize = 0.1f;
float spacing = sphereSize + sphereSize * 2f;
float startX = gridSize / 2 * spacing;
Vector3 startVector = new Vector3(startX, startX, 0);
float paramSteps = 1.0f / gridSize;
string texPrefix = "rustediron2_";
ITexture2D albedoText = contentLoader.Load <ITexture2D>(texPrefix + "basecolor.png");
ITexture2D metallicText = contentLoader.Load <ITexture2D>(texPrefix + "metallic.png");
ITexture2D normalText = contentLoader.Load <ITexture2D>(texPrefix + "normal.png");
ITexture2D roughnessText = contentLoader.Load <ITexture2D>(texPrefix + "roughness.png");
DefaultMesh mesh = contentLoader.Load <DefaultMesh>("uvSphere").Transform(Transformation.Scale(0.1f));
//DefaultMesh mesh = Meshes.CreateSphere(sphereSize, 2);
VAO geom = VAOLoader.FromMesh(mesh, renderer.GetPBRShader());
TangentSpaceData tangentData = GetTangentSpaceData(mesh.Position, mesh.TexCoord);
int tangentLocation = renderer.GetPBRShader().GetResourceLocation(ShaderResourceType.Attribute, "tangent");
int biTangentLocation = GL.GetAttribLocation(renderer.GetPBRShader().ProgramID, "biTangent");
geom.SetAttribute(tangentLocation, tangentData.tangent);
geom.SetAttribute(biTangentLocation, tangentData.biTangent);
for (int i = 0; i < gridSize; i++)
{
Vector3 tmpStart = startVector;
for (int j = 0; j < gridSize; j++)
{
GameObject go = new GameObject();
go.transform.position = tmpStart;
go.material.metal = i * paramSteps;
go.material.roughness = j * paramSteps;
go.material.albedoColor = new Vector3(1, 0, 0);
go.mesh = geom;
/*
* go.material.albedoMap = albedoText;
* go.material.metallicMap = metallicText;
* go.material.normalMap = normalText;
* go.material.roughnessMap = roughnessText;
*/
goList.Add(go);
tmpStart.X -= spacing;
}
startVector.Y -= spacing;
}
return(goList);
}