You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
293 lines
8.2 KiB
293 lines
8.2 KiB
![]()
4 years ago
|
//========= Copyright Valve Corporation, All rights reserved. ============//
|
||
|
//
|
||
|
// Purpose: A little helper class that computes a spline patch
|
||
|
//
|
||
|
// $Workfile: $
|
||
|
// $Date: $
|
||
|
//
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// $Log: $
|
||
|
//
|
||
|
// $NoKeywords: $
|
||
|
//=============================================================================//
|
||
|
#include "cbase.h"
|
||
|
#include "splinepatch.h"
|
||
|
|
||
|
#include "mathlib/vmatrix.h"
|
||
|
|
||
|
// memdbgon must be the last include file in a .cpp file!!!
|
||
|
#include "tier0/memdbgon.h"
|
||
|
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// Catmull rom blend weights
|
||
|
//-----------------------------------------------------------------------------
|
||
|
|
||
|
static VMatrix s_CatmullRom( -0.5, 1.5, -1.5, 0.5,
|
||
|
1, -2.5, 2, -0.5,
|
||
|
-0.5, 0, 0.5, 0,
|
||
|
0, 1, 0, 0 );
|
||
|
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// The last argument represents the number of float channels in addition to position
|
||
|
//-----------------------------------------------------------------------------
|
||
|
|
||
|
CSplinePatch::CSplinePatch( ) : m_ChannelCount(0),
|
||
|
m_Width(0), m_Height(0), m_ppPositions(0), m_LinearFactor(1.0f)
|
||
|
{
|
||
|
}
|
||
|
|
||
|
CSplinePatch::~CSplinePatch()
|
||
|
{
|
||
|
}
|
||
|
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// Initialize the spline patch
|
||
|
//-----------------------------------------------------------------------------
|
||
|
|
||
|
void CSplinePatch::Init( int w, int h, int extraChannels )
|
||
|
{
|
||
|
assert( extraChannels < MAX_CHANNELS );
|
||
|
m_ChannelCount = extraChannels;
|
||
|
m_Width = w;
|
||
|
m_Height = h;
|
||
|
m_LinearFactor = 1.0f;
|
||
|
}
|
||
|
|
||
|
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// 0 = linear, 1 = spliney!
|
||
|
//-----------------------------------------------------------------------------
|
||
|
|
||
|
void CSplinePatch::SetLinearBlend( float factor )
|
||
|
{
|
||
|
m_LinearFactor = factor;
|
||
|
}
|
||
|
|
||
|
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// Hooks the patch up to externally controlled data...
|
||
|
//-----------------------------------------------------------------------------
|
||
|
|
||
|
void CSplinePatch::SetControlPositions( Vector const** pPositions )
|
||
|
{
|
||
|
m_ppPositions = pPositions;
|
||
|
}
|
||
|
|
||
|
void CSplinePatch::SetChannelData( int channel, float* pChannel )
|
||
|
{
|
||
|
m_pChannel[channel] = pChannel;
|
||
|
}
|
||
|
|
||
|
static inline void ComputeIndex( int i, int maxval, int* idx )
|
||
|
{
|
||
|
if (i == 0)
|
||
|
{
|
||
|
idx[0] = 0; idx[1] = 0; idx[2] = 1;
|
||
|
idx[3] = (maxval > 2) ? 2 : 1;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
idx[0] = i-1; idx[1] = i;
|
||
|
if (i >= maxval - 1)
|
||
|
{
|
||
|
idx[2] = i; idx[3] = i;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
idx[2] = i+1;
|
||
|
if (i >= maxval - 2)
|
||
|
idx[3] = i+1;
|
||
|
else
|
||
|
idx[3]= i+2;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// Computes indices of the samples to read for this interpolation
|
||
|
//-----------------------------------------------------------------------------
|
||
|
|
||
|
void CSplinePatch::ComputeIndices( )
|
||
|
{
|
||
|
int s[4];
|
||
|
int t[4];
|
||
|
|
||
|
ComputeIndex( m_is, m_Width, s );
|
||
|
ComputeIndex( m_it, m_Height, t );
|
||
|
|
||
|
int base = t[0] * m_Width;
|
||
|
m_SampleIndices[0][0] = base + s[0];
|
||
|
m_SampleIndices[1][0] = base + s[1];
|
||
|
m_SampleIndices[2][0] = base + s[2];
|
||
|
m_SampleIndices[3][0] = base + s[3];
|
||
|
|
||
|
base = t[1] * m_Width;
|
||
|
m_SampleIndices[0][1] = base + s[0];
|
||
|
m_SampleIndices[1][1] = base + s[1];
|
||
|
m_SampleIndices[2][1] = base + s[2];
|
||
|
m_SampleIndices[3][1] = base + s[3];
|
||
|
|
||
|
base = t[2] * m_Width;
|
||
|
m_SampleIndices[0][2] = base + s[0];
|
||
|
m_SampleIndices[1][2] = base + s[1];
|
||
|
m_SampleIndices[2][2] = base + s[2];
|
||
|
m_SampleIndices[3][2] = base + s[3];
|
||
|
|
||
|
base = t[3] * m_Width;
|
||
|
m_SampleIndices[0][3] = base + s[0];
|
||
|
m_SampleIndices[1][3] = base + s[1];
|
||
|
m_SampleIndices[2][3] = base + s[2];
|
||
|
m_SampleIndices[3][3] = base + s[3];
|
||
|
}
|
||
|
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// Call this before querying the patch for data at (s,t)
|
||
|
//-----------------------------------------------------------------------------
|
||
|
|
||
|
void CSplinePatch::SetupPatchQuery( float s, float t )
|
||
|
{
|
||
|
m_is = (int)s;
|
||
|
m_it = (int)t;
|
||
|
|
||
|
if( m_is >= m_Width )
|
||
|
{
|
||
|
m_is = m_Width - 1;
|
||
|
m_fs = 1.0f;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
m_fs = s - m_is;
|
||
|
}
|
||
|
|
||
|
if( m_it >= m_Height )
|
||
|
{
|
||
|
m_it = m_Height - 1;
|
||
|
m_ft = 1.0f;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
m_ft = t - m_it;
|
||
|
}
|
||
|
|
||
|
ComputeIndices( );
|
||
|
|
||
|
// The patch equation is:
|
||
|
// px = S * M * Gx * M^T * T^T
|
||
|
// py = S * M * Gy * M^T * T^T
|
||
|
// pz = S * M * Gz * M^T * T^T
|
||
|
// where S = [s^3 s^2 s 1], T = [t^3 t^2 t 1]
|
||
|
// M is the patch type matrix, in my case I'm using a catmull-rom
|
||
|
// G is the array of control points. rows have constant t
|
||
|
|
||
|
// We're gonna cache off S * M and M^T * T^T...
|
||
|
Vector4D svec, tvec;
|
||
|
float fs2 = m_fs * m_fs;
|
||
|
svec[0] = fs2 * m_fs; svec[1] = fs2; svec[2] = m_fs; svec[3] = 1.0f;
|
||
|
float ft2 = m_ft * m_ft;
|
||
|
tvec[0] = ft2 * m_ft; tvec[1] = ft2; tvec[2] = m_ft; tvec[3] = 1.0f;
|
||
|
|
||
|
// This sets up the catmull rom matrix based on the blend factor!!
|
||
|
// we can go from linear to curvy!
|
||
|
s_CatmullRom.Init( -0.5 * m_LinearFactor, 1.5 * m_LinearFactor, -1.5 * m_LinearFactor, 0.5 * m_LinearFactor,
|
||
|
m_LinearFactor, -2.5 * m_LinearFactor, 2 * m_LinearFactor, -0.5 * m_LinearFactor,
|
||
|
-0.5 * m_LinearFactor, -1 + m_LinearFactor, 1 - 0.5 * m_LinearFactor, 0,
|
||
|
0, 1, 0, 0 );
|
||
|
Vector4DMultiplyTranspose( s_CatmullRom, svec, m_SVec );
|
||
|
Vector4DMultiplyTranspose( s_CatmullRom, tvec, m_TVec );
|
||
|
}
|
||
|
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// Gets the point and normal at (i,j) specified above
|
||
|
//-----------------------------------------------------------------------------
|
||
|
|
||
|
void CSplinePatch::GetPointAndNormal( Vector& position, Vector& normal ) const
|
||
|
{
|
||
|
// The patch equation is:
|
||
|
// px = S * M * Gx * M^T * T^T
|
||
|
// py = S * M * Gy * M^T * T^T
|
||
|
// pz = S * M * Gz * M^T * T^T
|
||
|
// where S = [s^3 s^2 s 1], T = [t^3 t^2 t 1]
|
||
|
// M is the patch type matrix, in my case I'm using a catmull-rom
|
||
|
// G is the array of control points. rows have constant t
|
||
|
|
||
|
VMatrix controlPointsX, controlPointsY, controlPointsZ;
|
||
|
for (int i = 0; i < 4; ++i)
|
||
|
{
|
||
|
for (int j = 0; j < 4; ++j)
|
||
|
{
|
||
|
int idx = m_SampleIndices[i][j];
|
||
|
controlPointsX[i][j] = m_ppPositions[ idx ]->x;
|
||
|
controlPointsY[i][j] = m_ppPositions[ idx ]->y;
|
||
|
controlPointsZ[i][j] = m_ppPositions[ idx ]->z;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
Vector4D tmp;
|
||
|
|
||
|
Vector4DMultiply( controlPointsX, m_TVec, tmp );
|
||
|
position[0] = DotProduct4D( tmp, m_SVec );
|
||
|
Vector4DMultiply( controlPointsY, m_TVec, tmp );
|
||
|
position[1] = DotProduct4D( tmp, m_SVec );
|
||
|
Vector4DMultiply( controlPointsZ, m_TVec, tmp );
|
||
|
position[2] = DotProduct4D( tmp, m_SVec );
|
||
|
|
||
|
// Normal computation
|
||
|
|
||
|
float fs2 = m_fs * m_fs;
|
||
|
float ft2 = m_ft * m_ft;
|
||
|
Vector4D dsvec( 3.0f * fs2, 2.0f * m_fs, 1.0f, 0.0f );
|
||
|
Vector4D dtvec( 3.0f * ft2, 2.0f * m_ft, 1.0f, 0.0f );
|
||
|
|
||
|
Vector4DMultiplyTranspose( s_CatmullRom, dsvec, dsvec );
|
||
|
Vector4DMultiplyTranspose( s_CatmullRom, dtvec, dtvec );
|
||
|
|
||
|
Vector ds, dt;
|
||
|
|
||
|
Vector4DMultiply( controlPointsX, m_TVec, tmp );
|
||
|
ds[0] = DotProduct4D( tmp, dsvec );
|
||
|
Vector4DMultiply( controlPointsY, m_TVec, tmp );
|
||
|
ds[1] = DotProduct4D( tmp, dsvec );
|
||
|
Vector4DMultiply( controlPointsZ, m_TVec, tmp );
|
||
|
ds[2] = DotProduct4D( tmp, dsvec );
|
||
|
|
||
|
Vector4DMultiply( controlPointsX, dtvec, tmp );
|
||
|
dt[0] = DotProduct4D( tmp, m_SVec );
|
||
|
Vector4DMultiply( controlPointsY, dtvec, tmp );
|
||
|
dt[1] = DotProduct4D( tmp, m_SVec );
|
||
|
Vector4DMultiply( controlPointsZ, dtvec, tmp );
|
||
|
dt[2] = DotProduct4D( tmp, m_SVec );
|
||
|
|
||
|
CrossProduct( ds, dt, normal );
|
||
|
VectorNormalize( normal );
|
||
|
}
|
||
|
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// Gets at other channels
|
||
|
//-----------------------------------------------------------------------------
|
||
|
|
||
|
float CSplinePatch::GetChannel( int channel ) const
|
||
|
{
|
||
|
// The patch equation is:
|
||
|
// px = S * M * Gx * M^T * T^T
|
||
|
// py = S * M * Gy * M^T * T^T
|
||
|
// pz = S * M * Gz * M^T * T^T
|
||
|
// where S = [s^3 s^2 s 1], T = [t^3 t^2 t 1]
|
||
|
// M is the patch type matrix, in my case I'm using a catmull-rom
|
||
|
// G is the array of control points. rows have constant t
|
||
|
|
||
|
assert( m_pChannel[channel] );
|
||
|
|
||
|
VMatrix controlPoints;
|
||
|
for (int i = 0; i < 4; ++i)
|
||
|
{
|
||
|
for (int j = 0; j < 4; ++j)
|
||
|
{
|
||
|
controlPoints[i][j] = m_pChannel[channel][ m_SampleIndices[i][j] ];
|
||
|
}
|
||
|
}
|
||
|
|
||
|
Vector4D tmp;
|
||
|
Vector4DMultiply( controlPoints, m_TVec, tmp );
|
||
|
return DotProduct4D( tmp, m_SVec );
|
||
|
}
|