/// <summary>
/// Build a look at view matrix.
/// transform object's coordinate from world's space to camera's space.
/// </summary>
/// <param name="eye">The eye.</param>
/// <param name="center">The center.</param>
/// <param name="up">Up.</param>
/// <returns></returns>
public static mat4 lookAt(vec3 eye, vec3 center, vec3 up)
{
// camera's back in world space coordinate system
vec3 back = (eye - center).normalize();
// camera's right in world space coordinate system
vec3 right = up.cross(back).normalize();
// camera's up in world space coordinate system
vec3 standardUp = back.cross(right);
mat4 viewMat = new mat4(1);
viewMat.col0.x = right.x;
viewMat.col1.x = right.y;
viewMat.col2.x = right.z;
viewMat.col0.y = standardUp.x;
viewMat.col1.y = standardUp.y;
viewMat.col2.y = standardUp.z;
viewMat.col0.z = back.x;
viewMat.col1.z = back.y;
viewMat.col2.z = back.z;
// Translation in world space coordinate system
viewMat.col3.x = -eye.dot(right);
viewMat.col3.y = -eye.dot(standardUp);
viewMat.col3.z = -eye.dot(back);
return(viewMat);
}
void IMouseHandler.canvas_MouseMove(object sender, MouseEventArgs e)
{
if (mouseDownFlag && ((e.Button & this.lastBindingMouseButtons) != MouseButtons.None))
{
if (!cameraState.IsSameState(this.camera))
{
SetCamera(this.camera.Position, this.camera.Target, this.camera.UpVector);
}
this._endPosition = GetArcBallPosition(e.X, e.Y);
var cosAngle = _startPosition.dot(_endPosition) / (_startPosition.length() * _endPosition.length());
if (cosAngle > 1.0f)
{
cosAngle = 1.0f;
}
else if (cosAngle < -1)
{
cosAngle = -1.0f;
}
var angle = MouseSensitivity * (float)(Math.Acos(cosAngle) / Math.PI * 180);
_normalVector = _startPosition.cross(_endPosition).normalize();
if (!
((_normalVector.x == 0 && _normalVector.y == 0 && _normalVector.z == 0) ||
float.IsNaN(_normalVector.x) || float.IsNaN(_normalVector.y) || float.IsNaN(_normalVector.z)))
{
_startPosition = _endPosition;
mat4 newRotation = glm.rotate(angle, _normalVector);
this.totalRotation = newRotation * totalRotation;
}
}
}
/// <summary>
/// Build a look at view matrix.
/// transform object's coordinate from world's space to camera's space.
/// </summary>
/// <param name="eye">The eye.</param>
/// <param name="center">The center.</param>
/// <param name="up">Up.</param>
/// <returns></returns>
public static mat4 lookAt(vec3 eye, vec3 center, vec3 up)
{
vec3 forward = (center - eye).normalize();
vec3 right = forward.cross(up).normalize();
vec3 standardUp = right.cross(forward);
mat4 Result = new mat4(1);
// Left (X) Axis
Result[0, 0] = right.x;
Result[0, 1] = standardUp.x;
Result[0, 2] = -forward.x;
// Up (Y) Axis
Result[1, 0] = right.y;
Result[1, 1] = standardUp.y;
Result[1, 2] = -forward.y;
// Forward (Z) Axis
Result[2, 0] = right.z;
Result[2, 1] = standardUp.z;
Result[2, 2] = -forward.z;
// Translation
Result[3, 0] = -right.dot(eye); // dot(s, eye);
Result[3, 1] = -standardUp.dot(eye); // dot(u, eye);
Result[3, 2] = forward.dot(eye); // dot(f, eye);
return(Result);
}
public void MouseMove(int x, int y)
{
if (MouseDownFlag)
{
Debug.WriteLine(" =================>MouseMove:", listenerName);
if (!cameraState.IsSameState(this.Camera))
{
SetCamera(this.Camera.Position, this.Camera.Target, this.Camera.UpVector);
Debug.WriteLine(string.Format(
" update camera state: {0}, {1}, {2}",
this.cameraState.position, this.cameraState.target, this.cameraState.up), listenerName);
}
this._endPosition = GetArcBallPosition(x, y);
Debug.WriteLine(string.Format(
" End position: {0}", this._endPosition), listenerName);
var cosAngle = _startPosition.dot(_endPosition) / (_startPosition.Magnitude() * _endPosition.Magnitude());
if (cosAngle > 1)
{
cosAngle = 1;
}
else if (cosAngle < -1)
{
cosAngle = -1;
}
Debug.Write(string.Format(" cos angle: {0}", cosAngle), listenerName);
var angle = mouseSensitivity * (float)(Math.Acos(cosAngle) / Math.PI * 180);
Debug.WriteLine(string.Format(
", angle: {0}", angle), listenerName);
_normalVector = _startPosition.cross(_endPosition).normalize();
if ((_normalVector.x == 0 && _normalVector.y == 0 && _normalVector.z == 0) ||
float.IsNaN(_normalVector.x) || float.IsNaN(_normalVector.y) || float.IsNaN(_normalVector.z))
{
Debug.WriteLine(" no movement recorded.", listenerName);
}
else
{
Debug.WriteLine(string.Format(
" normal vector: {0}", _normalVector), listenerName);
_startPosition = _endPosition;
mat4 newRotation = glm.rotate(angle, _normalVector);
Debug.WriteLine(string.Format(
" new rotation matrix: {0}", newRotation), listenerName);
this.totalRotation = newRotation * totalRotation;
Debug.WriteLine(string.Format(
" total rotation matrix: {0}", totalRotation), listenerName);
}
Debug.WriteLine(" -------------------MouseMove end.", listenerName);
}
}
// https://www.cnblogs.com/bitzhuwei/p/opengl-Computing-Tangent-Space-Basis-Vectors.html
public override void Parse(ObjVNFContext context)
{
ObjVNFMesh mesh = context.Mesh;
vec3[] vertexes = mesh.vertexes;// positions
vec2[] texCoords = mesh.texCoords;
vec3[] normals = mesh.normals;
if (vertexes == null || texCoords == null || normals == null)
{
return;
}
if (vertexes.Length != texCoords.Length || vertexes.Length != normals.Length)
{
return;
}
ObjVNFFace[] faces = mesh.faces;
if (faces == null || faces.Length == 0)
{
return;
}
// if (not triangles) { return; }
if (faces[0].VertexIndexes().Count() != 3)
{
return;
}
var tangents = new vec3[normals.Length];
var biTangents = new vec3[normals.Length];
for (int i = 0; i < faces.Length; i++)
{
var face = faces[i] as ObjVNFTriangle;
if (face == null)
{
return;
} // no dealing with quad.
uint[] vertexIndexes = face.VertexIndexes();
uint i0 = vertexIndexes[0];
uint i1 = vertexIndexes[1];
uint i2 = vertexIndexes[2];
vec3 p0 = vertexes[i0];
vec3 p1 = vertexes[i1];
vec3 p2 = vertexes[i2];
vec2 uv0 = texCoords[i0];
vec2 uv1 = texCoords[i1];
vec2 uv2 = texCoords[i2];
float x1 = p1.x - p0.x;
float y1 = p1.y - p0.y;
float z1 = p1.z - p0.z;
float x2 = p2.x - p0.x;
float y2 = p2.y - p0.y;
float z2 = p2.z - p0.z;
float s1 = uv1.x - uv0.x;
float t1 = uv1.y - uv0.y;
float s2 = uv2.x - uv0.x;
float t2 = uv2.y - uv0.y;
float r = 1.0F / (s1 * t2 - s2 * t1);
var sdir = new vec3((t2 * x1 - t1 * x2) * r, (t2 * y1 - t1 * y2) * r,
(t2 * z1 - t1 * z2) * r);
var tdir = new vec3((s1 * x2 - s2 * x1) * r, (s1 * y2 - s2 * y1) * r,
(s1 * z2 - s2 * z1) * r);
//tangents[i0] += sdir;
tangents[i0] = (float)i / (float)(i + 1) * tangents[i0] + sdir / (float)(i + 1);
//tangents[i1] += sdir;
tangents[i1] = (float)i / (float)(i + 1) * tangents[i1] + sdir / (float)(i + 1);
//tangents[i2] += sdir;
tangents[i2] = (float)i / (float)(i + 1) * tangents[i2] + sdir / (float)(i + 1);
//biTangents[i0] += tdir;
biTangents[i0] = (float)i / (float)(i + 1) * biTangents[i0] + sdir / (float)(i + 1);
//biTangents[i1] += tdir;
biTangents[i1] = (float)i / (float)(i + 1) * biTangents[i1] + sdir / (float)(i + 1);
//biTangents[i2] += tdir;
biTangents[i2] = (float)i / (float)(i + 1) * biTangents[i2] + sdir / (float)(i + 1);
}
var finalTangents = new vec4[normals.Length];
for (long a = 0; a < normals.Length; a++)
{
vec3 n = normals[a];
vec3 t = tangents[a];
// Calculate handedness
float w = (n.cross(t).dot(biTangents[a]) < 0.0F) ? -1.0F : 1.0F;
// Gram-Schmidt orthogonalize
finalTangents[a] = new vec4((t - n * n.dot(t)).normalize(), w);
}
mesh.tangents = finalTangents;
}