/// <summary>
/// Builds a rotation 4 * 4 matrix created from an axis vector and an angle.
/// </summary>
/// <param name="m">The m.</param>
/// <param name="angle">The angle.</param>
/// <param name="v">The v.</param>
/// <returns></returns>
public static mat4 rotate(mat4 m, float angle, vec3 v)
{
float c = cos(angle);
float s = sin(angle);
vec3 axis = v; axis.Normalize();// normalize(v);
vec3 temp = (1.0f - c) * axis;
mat4 rotate = mat4.identity();
rotate[0, 0] = c + temp[0] * axis[0];
rotate[0, 1] = 0 + temp[0] * axis[1] + s * axis[2];
rotate[0, 2] = 0 + temp[0] * axis[2] - s * axis[1];
rotate[1, 0] = 0 + temp[1] * axis[0] - s * axis[2];
rotate[1, 1] = c + temp[1] * axis[1];
rotate[1, 2] = 0 + temp[1] * axis[2] + s * axis[0];
rotate[2, 0] = 0 + temp[2] * axis[0] + s * axis[1];
rotate[2, 1] = 0 + temp[2] * axis[1] - s * axis[0];
rotate[2, 2] = c + temp[2] * axis[2];
mat4 result = mat4.identity();
result[0] = m[0] * rotate[0][0] + m[1] * rotate[0][1] + m[2] * rotate[0][2];
result[1] = m[0] * rotate[1][0] + m[1] * rotate[1][1] + m[2] * rotate[1][2];
result[2] = m[0] * rotate[2][0] + m[1] * rotate[2][1] + m[2] * rotate[2][2];
result[3] = m[3];
return(result);
}
public void MouseMove(int x, int y)
{
if (this.mouseDownFlag)
{
IViewCamera camera = this.Camera;
if (camera == null) { return; }
vec3 back = this.back;
vec3 right = this.right;
vec3 up = this.up;
Size bound = this.bound;
Point downPosition = this.downPosition;
{
float deltaX = -horizontalRotationFactor * (x - downPosition.X) / bound.Width;
float cos = (float)Math.Cos(deltaX);
float sin = (float)Math.Sin(deltaX);
vec3 newBack = new vec3(
back.x * cos + right.x * sin,
back.y * cos + right.y * sin,
back.z * cos + right.z * sin);
back = newBack;
right = up.cross(back);
back.Normalize();
right.Normalize();
}
{
float deltaY = verticalRotationFactor * (y - downPosition.Y) / bound.Height;
float cos = (float)Math.Cos(deltaY);
float sin = (float)Math.Sin(deltaY);
vec3 newBack = new vec3(
back.x * cos + up.x * sin,
back.y * cos + up.y * sin,
back.z * cos + up.z * sin);
back = newBack;
up = back.cross(right);
back.Normalize();
up.Normalize();
}
camera.Position = camera.Target +
back * (float)((camera.Position - camera.Target).Magnitude());
camera.UpVector = up;
this.back = back;
this.right = right;
this.up = up;
this.downPosition.X = x;
this.downPosition.Y = y;
}
}
/// <summary>
/// Build a look at view matrix.
/// </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 f = (center - eye); f.Normalize();
vec3 s = f.cross(up); s.Normalize();
vec3 u = s.cross(f);
mat4 Result = new mat4(1);
Result[0, 0] = s.x;
Result[1, 0] = s.y;
Result[2, 0] = s.z;
Result[0, 1] = u.x;
Result[1, 1] = u.y;
Result[2, 1] = u.z;
Result[0, 2] = -f.x;
Result[1, 2] = -f.y;
Result[2, 2] = -f.z;
Result[3, 0] = -s.dot(eye); // dot(s, eye);
Result[3, 1] = -u.dot(eye); // dot(u, eye);
Result[3, 2] = f.dot(eye); // dot(f, eye);
return(Result);
}
private static void GenNormals(ObjModel model)
{
if (model.normalList.Count > 0) { return; }
var faceNormals = new vec3[model.innerFaceList.Count];
model.normalList.AddRange(new vec3[model.positionList.Count]);
for (int i = 0; i < model.innerFaceList.Count; i++)
{
var face = model.innerFaceList[i];
vec3 vertex0 = model.positionList[face.vertex0.position - 1];
vec3 vertex1 = model.positionList[face.vertex1.position - 1];
vec3 vertex2 = model.positionList[face.vertex2.position - 1];
vec3 v1 = vertex0 - vertex2;
vec3 v2 = vertex2 - vertex1;
faceNormals[i] = v1.cross(v2);
}
for (int i = 0; i < model.positionList.Count; i++)
{
vec3 sum = new vec3();
int shared = 0;
for (int j = 0; j < model.innerFaceList.Count; j++)
{
var face = model.innerFaceList[j];
if (face.vertex0.position - 1 == i || face.vertex1.position - 1 == i || face.vertex2.position - 1 == i)
{
sum = sum + faceNormals[i];
shared++;
}
}
if (shared > 0)
{
sum = sum / shared;
sum.Normalize();
}
model.normalList[i] = sum;
}
}
private static void GetBackAndUp(out vec3 target2Position, out vec3 upVector, ViewTypes viewType)
{
switch (viewType)
{
case ViewTypes.UserView:
//UserView 定义为从顶视图开始，绕X 轴旋转30 度，在绕Z 轴45 度，并且能看到整个模型的虚拟模型空间。
target2Position = new vec3((float)Math.Sqrt(3), (float)Math.Sqrt(3), -1);
target2Position.Normalize();
upVector = new vec3(0, 0, -1);
break;
case ViewTypes.Top:
target2Position = new vec3(0, 0, -1);
upVector = new vec3(0, -1, 0);
break;
case ViewTypes.Bottom:
target2Position = new vec3(0, 0, 1);
upVector = new vec3(0, -1, 0);
break;
case ViewTypes.Left:
target2Position = new vec3(-1, 0, 0);
upVector = new vec3(0, 0, -1);
break;
case ViewTypes.Right:
target2Position = new vec3(1, 0, 0);
upVector = new vec3(0, 0, -1);
break;
case ViewTypes.Front:
target2Position = new vec3(0, 1, 0);
upVector = new vec3(0, 0, -1);
break;
case ViewTypes.Back:
target2Position = new vec3(0, -1, 0);
upVector = new vec3(0, 0, -1);
break;
default:
throw new NotImplementedException(string.Format("new value({0}) of EViewType is not implemented!", viewType));
//break;
}
}
private static void GenNormals(TeapotModel model)
{
var faceNormals = new vec3[model.faces.Count];
model.normals.AddRange(new vec3[model.positions.Count]);
for (int i = 0; i < model.faces.Count; i++)
{
var face = model.faces[i];
vec3 vertex0 = model.positions[face.Item1 - 1];
vec3 vertex1 = model.positions[face.Item2 - 1];
vec3 vertex2 = model.positions[face.Item3 - 1];
vec3 v1 = vertex0 - vertex2;
vec3 v2 = vertex2 - vertex1;
faceNormals[i] = v1.cross(v2);
}
for (int i = 0; i < model.positions.Count; i++)
{
vec3 sum = new vec3();
int shared = 0;
for (int j = 0; j < model.faces.Count; j++)
{
var face = model.faces[j];
if (face.Item1 - 1 == i || face.Item2 - 1 == i || face.Item3 - 1 == i)
{
sum = sum + faceNormals[i];
shared++;
}
}
if (shared > 0)
{
sum = sum / shared;
sum.Normalize();
}
model.normals[i] = sum;
}
}
