leocad/common/algebra.cpp

510 lines
14 KiB
C++

//
// Math and Linear Algebra stuff.
//
#include "lc_global.h"
#include <float.h>
#include "algebra.h"
// ============================================================================
// 4x4 Matrix class.
void Matrix44::CreateLookAt(const Vector3& Eye, const Vector3& Target, const Vector3& Up)
{
Vector3 x, y, z;
// Z = Eye - Target
z = Eye - Target;
// X = Y Cross Z
x = Cross3(Up, z);
// Y = Z Cross X
y = Cross3(z, x);
// Normalize everything.
x.Normalize();
y.Normalize();
z.Normalize();
m_Rows[0] = Vector4(x[0], y[0], z[0], 0.0f);
m_Rows[1] = Vector4(x[1], y[1], z[1], 0.0f);
m_Rows[2] = Vector4(x[2], y[2], z[2], 0.0f);
m_Rows[3] = m_Rows[0]*-Eye[0] + m_Rows[1]*-Eye[1] + m_Rows[2]*-Eye[2];
m_Rows[3][3] = 1.0f;
}
void Matrix44::CreatePerspective(float FoVy, float Aspect, float Near, float Far)
{
float Left, Right, Bottom, Top;
Top = Near * (float)tan(FoVy * LC_PI / 360.0f);
Bottom = -Top;
Left = Bottom * Aspect;
Right = Top * Aspect;
if ((Near <= 0.0f) || (Far <= 0.0f) || (Near == Far) || (Left == Right) || (Top == Bottom))
return;
float x, y, a, b, c, d;
x = (2.0f * Near) / (Right - Left);
y = (2.0f * Near) / (Top - Bottom);
a = (Right + Left) / (Right - Left);
b = (Top + Bottom) / (Top - Bottom);
c = -(Far + Near) / (Far - Near);
d = -(2.0f * Far * Near) / (Far - Near);
m_Rows[0] = Vector4(x, 0, 0, 0);
m_Rows[1] = Vector4(0, y, 0, 0);
m_Rows[2] = Vector4(a, b, c, -1);
m_Rows[3] = Vector4(0, 0, d, 0);
}
void Matrix44::CreateOrtho(float Left, float Right, float Bottom, float Top, float Near, float Far)
{
m_Rows[0] = Vector4(2.0f / (Right-Left), 0.0f, 0.0f, 0.0f);
m_Rows[1] = Vector4(0.0f, 2.0f / (Top-Bottom), 0.0f, 0.0f);
m_Rows[2] = Vector4(0.0f, 0.0f, -2.0f / (Far-Near), 0.0f);
m_Rows[3] = Vector4(-(Right+Left) / (Right-Left), -(Top+Bottom) / (Top-Bottom), -(Far+Near) / (Far-Near), 1.0f);
}
void GetFrustumPlanes(const Matrix44& WorldView, const Matrix44& Projection, Vector4 Planes[6])
{
// TODO: Use vectors.
Matrix44 WorldProj = Mul(WorldView, Projection);
Planes[0][0] = (WorldProj[0][0] - WorldProj[0][3]) * -1;
Planes[0][1] = (WorldProj[1][0] - WorldProj[1][3]) * -1;
Planes[0][2] = (WorldProj[2][0] - WorldProj[2][3]) * -1;
Planes[0][3] = (WorldProj[3][0] - WorldProj[3][3]) * -1;
Planes[1][0] = WorldProj[0][0] + WorldProj[0][3];
Planes[1][1] = WorldProj[1][0] + WorldProj[1][3];
Planes[1][2] = WorldProj[2][0] + WorldProj[2][3];
Planes[1][3] = WorldProj[3][0] + WorldProj[3][3];
Planes[2][0] = (WorldProj[0][1] - WorldProj[0][3]) * -1;
Planes[2][1] = (WorldProj[1][1] - WorldProj[1][3]) * -1;
Planes[2][2] = (WorldProj[2][1] - WorldProj[2][3]) * -1;
Planes[2][3] = (WorldProj[3][1] - WorldProj[3][3]) * -1;
Planes[3][0] = WorldProj[0][1] + WorldProj[0][3];
Planes[3][1] = WorldProj[1][1] + WorldProj[1][3];
Planes[3][2] = WorldProj[2][1] + WorldProj[2][3];
Planes[3][3] = WorldProj[3][1] + WorldProj[3][3];
Planes[4][0] = (WorldProj[0][2] - WorldProj[0][3]) * -1;
Planes[4][1] = (WorldProj[1][2] - WorldProj[1][3]) * -1;
Planes[4][2] = (WorldProj[2][2] - WorldProj[2][3]) * -1;
Planes[4][3] = (WorldProj[3][2] - WorldProj[3][3]) * -1;
Planes[5][0] = WorldProj[0][2] + WorldProj[0][3];
Planes[5][1] = WorldProj[1][2] + WorldProj[1][3];
Planes[5][2] = WorldProj[2][2] + WorldProj[2][3];
Planes[5][3] = WorldProj[3][2] + WorldProj[3][3];
for (int i = 0; i < 6; i++)
{
float Len = Vector3(Planes[i]).Length();
Planes[i] /= -Len;
}
}
Vector3 ZoomExtents(const Vector3& Position, const Matrix44& WorldView, const Matrix44& Projection, const Vector3* Points, int NumPoints)
{
if (!NumPoints)
return Position;
Vector4 Planes[6];
GetFrustumPlanes(WorldView, Projection, Planes);
Vector3 Front = Vector3(WorldView[0][2], WorldView[1][2], WorldView[2][2]);
// Calculate the position that is as close as possible to the model and has all pieces visible.
float SmallestDistance = FLT_MAX;
for (int p = 0; p < 4; p++)
{
float ep = Dot3(Position, Planes[p]);
float fp = Dot3(Front, Planes[p]);
for (int j = 0; j < NumPoints; j++)
{
// Intersect the camera line with the plane that contains this point, NewEye = Eye + u * (Target - Eye)
float u = (ep - Dot3(Points[j], Planes[p])) / fp;
if (u < SmallestDistance)
SmallestDistance = u;
}
}
return Position - (Front * SmallestDistance);
}
// Inverse code from the GLU library.
Matrix44 Inverse(const Matrix44& m)
{
#define SWAP_ROWS(a, b) { float *_tmp = a; (a)=(b); (b)=_tmp; }
#define MAT(m,c,r) m.m_Rows[r][c]
float wtmp[4][8];
float m0, m1, m2, m3, s;
float *r0, *r1, *r2, *r3;
r0 = wtmp[0], r1 = wtmp[1], r2 = wtmp[2], r3 = wtmp[3];
r0[0] = MAT(m,0,0), r0[1] = MAT(m,0,1),
r0[2] = MAT(m,0,2), r0[3] = MAT(m,0,3),
r0[4] = 1.0, r0[5] = r0[6] = r0[7] = 0.0,
r1[0] = MAT(m,1,0), r1[1] = MAT(m,1,1),
r1[2] = MAT(m,1,2), r1[3] = MAT(m,1,3),
r1[5] = 1.0, r1[4] = r1[6] = r1[7] = 0.0,
r2[0] = MAT(m,2,0), r2[1] = MAT(m,2,1),
r2[2] = MAT(m,2,2), r2[3] = MAT(m,2,3),
r2[6] = 1.0, r2[4] = r2[5] = r2[7] = 0.0,
r3[0] = MAT(m,3,0), r3[1] = MAT(m,3,1),
r3[2] = MAT(m,3,2), r3[3] = MAT(m,3,3),
r3[7] = 1.0, r3[4] = r3[5] = r3[6] = 0.0;
// choose pivot - or die
if (fabs(r3[0])>fabs(r2[0])) SWAP_ROWS(r3, r2);
if (fabs(r2[0])>fabs(r1[0])) SWAP_ROWS(r2, r1);
if (fabs(r1[0])>fabs(r0[0])) SWAP_ROWS(r1, r0);
// if (0.0 == r0[0]) return GL_FALSE;
// eliminate first variable
m1 = r1[0]/r0[0]; m2 = r2[0]/r0[0]; m3 = r3[0]/r0[0];
s = r0[1]; r1[1] -= m1 * s; r2[1] -= m2 * s; r3[1] -= m3 * s;
s = r0[2]; r1[2] -= m1 * s; r2[2] -= m2 * s; r3[2] -= m3 * s;
s = r0[3]; r1[3] -= m1 * s; r2[3] -= m2 * s; r3[3] -= m3 * s;
s = r0[4];
if (s != 0.0) { r1[4] -= m1 * s; r2[4] -= m2 * s; r3[4] -= m3 * s; }
s = r0[5];
if (s != 0.0) { r1[5] -= m1 * s; r2[5] -= m2 * s; r3[5] -= m3 * s; }
s = r0[6];
if (s != 0.0) { r1[6] -= m1 * s; r2[6] -= m2 * s; r3[6] -= m3 * s; }
s = r0[7];
if (s != 0.0) { r1[7] -= m1 * s; r2[7] -= m2 * s; r3[7] -= m3 * s; }
// choose pivot - or die
if (fabs(r3[1])>fabs(r2[1])) SWAP_ROWS(r3, r2);
if (fabs(r2[1])>fabs(r1[1])) SWAP_ROWS(r2, r1);
// if (0.0 == r1[1]) return GL_FALSE;
// eliminate second variable
m2 = r2[1]/r1[1]; m3 = r3[1]/r1[1];
r2[2] -= m2 * r1[2]; r3[2] -= m3 * r1[2];
r2[3] -= m2 * r1[3]; r3[3] -= m3 * r1[3];
s = r1[4]; if (0.0 != s) { r2[4] -= m2 * s; r3[4] -= m3 * s; }
s = r1[5]; if (0.0 != s) { r2[5] -= m2 * s; r3[5] -= m3 * s; }
s = r1[6]; if (0.0 != s) { r2[6] -= m2 * s; r3[6] -= m3 * s; }
s = r1[7]; if (0.0 != s) { r2[7] -= m2 * s; r3[7] -= m3 * s; }
// choose pivot - or die
if (fabs(r3[2])>fabs(r2[2])) SWAP_ROWS(r3, r2);
// if (0.0 == r2[2]) return GL_FALSE;
// eliminate third variable
m3 = r3[2]/r2[2];
r3[3] -= m3 * r2[3], r3[4] -= m3 * r2[4],
r3[5] -= m3 * r2[5], r3[6] -= m3 * r2[6],
r3[7] -= m3 * r2[7];
// last check
// if (0.0 == r3[3]) return GL_FALSE;
s = 1.0f/r3[3]; // now back substitute row 3
r3[4] *= s; r3[5] *= s; r3[6] *= s; r3[7] *= s;
m2 = r2[3]; // now back substitute row 2
s = 1.0f/r2[2];
r2[4] = s * (r2[4] - r3[4] * m2), r2[5] = s * (r2[5] - r3[5] * m2),
r2[6] = s * (r2[6] - r3[6] * m2), r2[7] = s * (r2[7] - r3[7] * m2);
m1 = r1[3];
r1[4] -= r3[4] * m1, r1[5] -= r3[5] * m1,
r1[6] -= r3[6] * m1, r1[7] -= r3[7] * m1;
m0 = r0[3];
r0[4] -= r3[4] * m0, r0[5] -= r3[5] * m0,
r0[6] -= r3[6] * m0, r0[7] -= r3[7] * m0;
m1 = r1[2]; // now back substitute row 1
s = 1.0f/r1[1];
r1[4] = s * (r1[4] - r2[4] * m1), r1[5] = s * (r1[5] - r2[5] * m1),
r1[6] = s * (r1[6] - r2[6] * m1), r1[7] = s * (r1[7] - r2[7] * m1);
m0 = r0[2];
r0[4] -= r2[4] * m0, r0[5] -= r2[5] * m0,
r0[6] -= r2[6] * m0, r0[7] -= r2[7] * m0;
m0 = r0[1]; // now back substitute row 0
s = 1.0f/r0[0];
r0[4] = s * (r0[4] - r1[4] * m0), r0[5] = s * (r0[5] - r1[5] * m0),
r0[6] = s * (r0[6] - r1[6] * m0), r0[7] = s * (r0[7] - r1[7] * m0);
Vector4 Row0(r0[4], r1[4], r2[4], r3[4]);
Vector4 Row1(r0[5], r1[5], r2[5], r3[5]);
Vector4 Row2(r0[6], r1[6], r2[6], r3[6]);
Vector4 Row3(r0[7], r1[7], r2[7], r3[7]);
Matrix44 out(Row0, Row1, Row2, Row3);
return out;
#undef MAT
#undef SWAP_ROWS
}
// ============================================================================
// Project/Unproject a point.
// Convert world coordinates to screen coordinates.
Vector3 ProjectPoint(const Vector3& Pt, const Matrix44& ModelView, const Matrix44& Projection, const int Viewport[4])
{
Vector4 Tmp;
Tmp = Mul4(Vector4(Pt[0], Pt[1], Pt[2], 1.0f), ModelView);
Tmp = Mul4(Tmp, Projection);
// Normalize.
Tmp /= Tmp[3];
// Screen coordinates.
return Vector3(Viewport[0]+(1+Tmp[0])*Viewport[2]/2, Viewport[1]+(1+Tmp[1])*Viewport[3]/2, (1+Tmp[2])/2);
}
void ProjectPoints(Vector3* Points, int NumPoints, const Matrix44& ModelView, const Matrix44& Projection, const int Viewport[4])
{
for (int i = 0; i < NumPoints; i++)
{
Vector4 Tmp;
Tmp = Mul4(Vector4(Points[i][0], Points[i][1], Points[i][2], 1.0f), ModelView);
Tmp = Mul4(Tmp, Projection);
// Normalize.
Tmp /= Tmp[3];
// Screen coordinates.
Points[i] = Vector3(Viewport[0]+(1+Tmp[0])*Viewport[2]/2, Viewport[1]+(1+Tmp[1])*Viewport[3]/2, (1+Tmp[2])/2);
}
}
// Convert screen coordinates to world coordinates.
Vector3 UnprojectPoint(const Vector3& Point, const Matrix44& ModelView, const Matrix44& Projection, const int Viewport[4])
{
Vector3 Tmp = Point;
UnprojectPoints(&Tmp, 1, ModelView, Projection, Viewport);
return Tmp;
}
void UnprojectPoints(Vector3* Points, int NumPoints, const Matrix44& ModelView, const Matrix44& Projection, const int Viewport[4])
{
// Calculate the screen to model transform.
Matrix44 Transform = Inverse(Mul(ModelView, Projection));
for (int i = 0; i < NumPoints; i++)
{
Vector4 Tmp;
// Convert the point to homogeneous coordinates.
Tmp[0] = (Points[i][0] - Viewport[0]) * 2.0f / Viewport[2] - 1.0f;
Tmp[1] = (Points[i][1] - Viewport[1]) * 2.0f / Viewport[3] - 1.0f;
Tmp[2] = Points[i][2] * 2.0f - 1.0f;
Tmp[3] = 1.0f;
Tmp = Mul4(Tmp, Transform);
if (Tmp[3] != 0.0f)
Tmp /= Tmp[3];
Points[i] = Vector3(Tmp[0], Tmp[1], Tmp[2]);
}
}
// ============================================================================
// Geometry functions.
// Sutherland-Hodgman method of clipping a polygon to a plane.
void PolygonPlaneClip(Vector3* InPoints, int NumInPoints, Vector3* OutPoints, int* NumOutPoints, const Vector4& Plane)
{
Vector3 *s, *p, i;
*NumOutPoints = 0;
s = &InPoints[NumInPoints-1];
for (int j = 0; j < NumInPoints; j++)
{
p = &InPoints[j];
if (Dot3(*p, Plane) + Plane[3] <= 0)
{
if (Dot3(*s, Plane) + Plane[3] <= 0)
{
// Both points inside.
OutPoints[*NumOutPoints] = *p;
*NumOutPoints = *NumOutPoints + 1;
}
else
{
// Outside, inside.
LinePlaneIntersection(i, *s, *p, Plane);
OutPoints[*NumOutPoints] = i;
*NumOutPoints = *NumOutPoints + 1;
OutPoints[*NumOutPoints] = *p;
*NumOutPoints = *NumOutPoints + 1;
}
}
else
{
if (Dot3(*s, Plane) + Plane[3] <= 0)
{
// Inside, outside.
LinePlaneIntersection(i, *s, *p, Plane);
OutPoints[*NumOutPoints] = i;
*NumOutPoints = *NumOutPoints + 1;
}
}
s = p;
}
}
// Calculate the intersection of a line segment and a plane and returns false
// if they are parallel or the intersection is outside the line segment.
bool LinePlaneIntersection(Vector3& Intersection, const Vector3& Start, const Vector3& End, const Vector4& Plane)
{
Vector3 Dir = End - Start;
float t1 = Dot3(Plane, Start) + Plane[3];
float t2 = Dot3(Plane, Dir);
if (t2 == 0.0f)
return false;
float t = -t1 / t2;
Intersection = Start + t * Dir;
if ((t < 0.0f) || (t > 1.0f))
return false;
return true;
}
bool LineTriangleMinIntersection(const Vector3& p1, const Vector3& p2, const Vector3& p3, const Vector3& Start, const Vector3& End, float& MinDist, Vector3& Intersection)
{
// Calculate the polygon plane.
Vector4 Plane;
Plane = Cross3(p1 - p2, p3 - p2);
Plane[3] = -Dot3(Plane, p1);
// Check if the line is parallel to the plane.
Vector3 Dir = End - Start;
float t1 = Dot3(Plane, Start) + Plane[3];
float t2 = Dot3(Plane, Dir);
if (t2 == 0)
return false;
float t = -(t1 / t2);
if (t < 0)
return false;
// Intersection of the plane and line segment.
Intersection = Start - (t1 / t2) * Dir;
float Dist = (Start - Intersection).Length();
if (Dist > MinDist)
return false;
// Check if we're inside the triangle.
Vector3 pa1, pa2, pa3;
pa1 = (p1 - Intersection).Normalize();
pa2 = (p2 - Intersection).Normalize();
pa3 = (p3 - Intersection).Normalize();
float a1, a2, a3;
a1 = Dot3(pa1, pa2);
a2 = Dot3(pa2, pa3);
a3 = Dot3(pa3, pa1);
float total = (acosf(a1) + acosf(a2) + acosf(a3)) * RTOD;
if (fabs(total - 360) <= 0.001f)
{
MinDist = Dist;
return true;
}
return false;
}
bool LineQuadMinIntersection(const Vector3& p1, const Vector3& p2, const Vector3& p3, const Vector3& p4, const Vector3& Start, const Vector3& End, float& MinDist, Vector3& Intersection)
{
// Calculate the polygon plane.
Vector4 Plane;
Plane = Cross3(p1 - p2, p3 - p2);
Plane[3] = -Dot3(Plane, p1);
// Check if the line is parallel to the plane.
Vector3 Dir = End - Start;
float t1 = Dot3(Plane, Start) + Plane[3];
float t2 = Dot3(Plane, Dir);
if (t2 == 0)
return false;
float t = -(t1 / t2);
if (t < 0)
return false;
// Intersection of the plane and line segment.
Intersection = Start - (t1 / t2) * Dir;
float Dist = (Start - Intersection).Length();
if (Dist > MinDist)
return false;
// Check if we're inside the triangle.
Vector3 pa1, pa2, pa3;
pa1 = (p1 - Intersection).Normalize();
pa2 = (p2 - Intersection).Normalize();
pa3 = (p3 - Intersection).Normalize();
float a1, a2, a3;
a1 = Dot3(pa1, pa2);
a2 = Dot3(pa2, pa3);
a3 = Dot3(pa3, pa1);
float total = (acosf(a1) + acosf(a2) + acosf(a3)) * RTOD;
if (fabs(total - 360) <= 0.001f)
{
MinDist = Dist;
return true;
}
// Check if we're inside the second triangle.
pa2 = (p4 - Intersection).Normalize();
a1 = Dot3(pa1, pa2);
a2 = Dot3(pa2, pa3);
a3 = Dot3(pa3, pa1);
total = (acosf(a1) + acosf(a2) + acosf(a3)) * RTOD;
if (fabs(total - 360) <= 0.001f)
{
MinDist = Dist;
return true;
}
return false;
}