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Line3d.cpp
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Line3d.cpp
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/*
LINE3D.CPP a program to investigate the Mandelbrot set. This version reads
values of count from file and displays the data transformed into
a 3 dimensional image. For more information refer to Scientific
American August 1985.
Written in Microsoft Visual 'C++' by Paul de Leeuw.
This program is written in "standard" C. Hardware dependant code
(console drivers & serial I/O) is in separate machine libraries.
*/
#include "manp.h"
#include "colour.h"
#include "Matrix.h"
#include "pixel.h"
/**************************************************************************
Initialise 3D parameters
**************************************************************************/
void CPixel::init3d(int xdots, int ydots, double x_rot, double y_rot, double z_rot, double sclx, double scly, double sclz, long threshold, double hor, double vert)
{
CMatrix Mat;
Mat.identity(m); // start with identity
// translate so origin is in centre, so that we rotate through the centre
Mat.trans((double) xdots / (-2.0), (double) ydots / (-2.0), 0.0, m);
Mat.scale(sclx, scly, sclz, m); /* apply scale factors */
xval = x_rot / 57.29577; /* rot values - convert degrees to radians */
yval = y_rot / 57.29577;
zval = z_rot / 57.29577;
Mat.xrot(xval, m);
Mat.yrot(yval, m);
Mat.zrot(zval, m);
Mat.trans((double) xdots / (2.0), (double) ydots / (2.0), 0.0, m);
}
/**************************************************************************
Project 3 dimensions onto 2
**************************************************************************/
void CPixel::projection(int x, int y, long col)
{
VECTOR w;
struct PointInfo cur; // current pixels
int colour;
CMatrix Mat;
colour = (col >= MAXTHRESHOLD) ? MAXTHRESHOLD : (int)col; // reduce to 15 bits
cur.colour = colour;
w[0] = (double) x;
w[1] = (double) y;
w[2] = (double) colour;
Mat.vmult(w, m, w);
cur.x = (int) (w[0]);
cur.y = (int) (w[1]);
if (y > 0 && x > 0)
do_line((short)cur.x, (short)cur.y, (short)oldpoint.x, (short)oldpoint.y, (short)oldpoint.colour, (short)cur.colour);
oldpoint.x = cur.x;
oldpoint.y = cur.y;
oldpoint.colour = cur.colour;
if (y > 0 && x > 0)
do_line((short)cur.x, (short)cur.y, (short)oldline[x].x, (short)oldline[x].y, (short)oldline[x].colour, (short)cur.colour);
oldline[x].x = cur.x;
oldline[x].y = cur.y;
oldline[x].colour = cur.colour;
}
#ifdef SPLAT
/***************************************************************************
Initialise a matrix and set to identity matrix
***************************************************************************/
void CPixel::identity(MATRIXPTR m)
{
int i, j;
for (i = 0; i < 4; i++)
for (j = 0; j < 4; j++)
if (i == j)
m[j][i] = 1.0;
else
m[j][i] = 0.0;
}
/***************************************************************************
Multiply two matrices Result stored in MATRIX new to avoid problems
in case parameter mat3 == mat2 or mat 1
***************************************************************************/
void CPixel::mat_mul(MATRIXPTR mat1, MATRIXPTR mat2, MATRIXPTR mat3)
{
MATRIX New;
int i, j;
for (i = 0; i < 4; i++)
for (j = 0; j < 4; j++)
New[j][i] = mat1[j][0] * mat2[0][i] + mat1[j][1] * mat2[1][i]
+ mat1[j][2] * mat2[2][i] + mat1[j][3]*mat2[3][i];
/* should replace this with memcpy */
for (i = 0; i < 4; i++)
for (j = 0; j < 4; j++)
mat3[j][i] = New[j][i];
}
/***************************************************************************
Multiply a matrix by a scalar
***************************************************************************/
void CPixel::scale(double sx, double sy, double sz, MATRIXPTR m)
{
MATRIX scale;
identity(scale);
scale[0][0] = sx;
scale[1][1] = sy;
scale[2][2] = sz;
mat_mul(m, scale, m);
}
/***************************************************************************
Rotate about X axis
***************************************************************************/
void CPixel::xrot(double theta, MATRIXPTR m)
{
MATRIX rot;
double sintheta, costheta;
sintheta = sin(theta);
costheta = cos(theta);
identity(rot);
rot[1][1] = costheta;
rot[1][2] = -sintheta;
rot[2][1] = sintheta;
rot[2][2] = costheta;
mat_mul(m, rot, m);
}
/***************************************************************************
Rotate about Y axis
***************************************************************************/
void CPixel::yrot(double theta, MATRIXPTR m)
{
MATRIX rot;
double sintheta, costheta;
sintheta = sin(theta);
costheta = cos(theta);
identity(rot);
rot[0][0] = costheta;
rot[0][2] = sintheta;
rot[2][0] = -sintheta;
rot[2][2] = costheta;
mat_mul(m, rot, m);
}
/***************************************************************************
Rotate about Z axis
***************************************************************************/
void CPixel::zrot(double theta, MATRIXPTR m)
{
MATRIX rot;
double sintheta, costheta;
sintheta = sin(theta);
costheta = cos(theta);
identity(rot);
rot[0][0] = costheta;
rot[0][1] = -sintheta;
rot[1][0] = sintheta;
rot[1][1] = costheta;
mat_mul(m, rot, m);
}
/***************************************************************************
Translate matrix
***************************************************************************/
void CPixel::trans(double tx, double ty, double tz, MATRIXPTR m)
{
MATRIX trans;
identity(trans);
trans[3][0] = tx;
trans[3][1] = ty;
trans[3][2] = tz;
mat_mul(m, trans, m);
}
/***************************************************************************
Multiply source vector s by matrix m, result in target t
***************************************************************************/
int CPixel::vmult(VECTORPTR s, MATRIXPTR m, VECTORPTR t)
{
VECTOR tmp;
int i, j;
for (j = 0; j < 3; j++)
{
tmp[j] = 0.0;
for (i = 0; i < 3; i++)
tmp[j] += s[i] * m[i][j];
// vector is really four dimensional with last component always 1
tmp[j] += m[3][j];
}
// set target = tmp. Necessary to use tmp in case source = target
for (i = 0; i < 3; i++)
t[i] = tmp[i];
return (0);
}
#endif
/***************************************************************************
Interpolate colours
***************************************************************************/
void CPixel::interpcolour(short x0, short y0, short x1, short y1,
int x, int y, int col0, int col1)
{
int colour;
long d1, d2, col;
if ((abs(x1 - x0)) > (abs(y1 - y0)) && (x1 - x0) != 0)
{
d1 = (long) (x1 - x);
d2 = (long) (x1 - x0);
}
else if (y1 - y0 != 0)
{
d1 = (long) (y1 - y);
d2 = (long) (y1 - y0);
}
else
d1 = d2 = 1l;
col = (long) (col1 - col0);
colour = abs(col0 + (int) ((col * d1) / d2));
if (2 <= x && x <= (int)xdots - 3 && 2 <= y && y <= (int)ydots - 3)
if (0 < colour)
PlotPixel((WORD)x, (WORD)y, colour);
}
/**************************************************************************
Draw a line from raw x0,y0 to x1,y1 and interp colour
**************************************************************************/
void CPixel::do_line(short x0, short y0, short x1, short y1, short col0, short col1)
{
register short xlo, ylo;
register short c;
short xhi, yhi;
long a, b;
ylo = min(y0, y1);
yhi = max(y0, y1);
xlo = min(x0, x1);
xhi = max(x0, x1);
if (x0 == x1)
{
while (ylo <= yhi)
interpcolour(x0, y0, x1, y1, x0, ylo++, col0, col1);
}
else if (y0 == y1)
{
while (xlo <= xhi)
interpcolour(x0, y0, x1, y1, xlo++, y0, col0, col1);
}
else
{
a = (x1 - x0); b = (y1 - y0); c = 0;
if (xhi-xlo > yhi-ylo)
{
y0 = (xlo == x0) ? y0 : y1;
while (xlo <= xhi)
interpcolour(x0, y0, x1, y1,
xlo++, (short)(y0 + (b * c++) / a), col0, col1);
}
else
{
x0 = (ylo == y0) ? x0 : x1;
while (ylo <= yhi)
interpcolour(x0, y0, x1, y1,
(short)(x0 + (a * c++) / b), ylo++, col0, col1);
}
}
}