paysages3d/src/rendering/tools.c
2013-04-17 12:29:51 +00:00

56 lines
1.6 KiB
C

#include "tools.h"
#include <assert.h>
#include <stdlib.h>
#include <inttypes.h>
#include <math.h>
double toolsRandom()
{
return ((double)rand()) / (double)RAND_MAX;
}
static inline double _cubicInterpolate(double p[4], double x)
{
return p[1] + 0.5 * x * (p[2] - p[0] + x * (2.0 * p[0] - 5.0 * p[1] + 4.0 * p[2] - p[3] + x * (3.0 * (p[1] - p[2]) + p[3] - p[0])));
}
double toolsCubicInterpolate(double stencil[4], double x)
{
return _cubicInterpolate(stencil, x);
}
double toolsBicubicInterpolate(double stencil[16], double x, double y)
{
double buf_cubic_y[4];
buf_cubic_y[0] = _cubicInterpolate(stencil, x);
buf_cubic_y[1] = _cubicInterpolate(stencil + 4, x);
buf_cubic_y[2] = _cubicInterpolate(stencil + 8, x);
buf_cubic_y[3] = _cubicInterpolate(stencil + 12, x);
return _cubicInterpolate(buf_cubic_y, y);
}
void toolsFloat2DMapCopy(double* src, double* dest, int src_xstart, int src_ystart, int dest_xstart, int dest_ystart, int xsize, int ysize, int src_xstep, int src_ystep, int dest_xstep, int dest_ystep)
{
/* TODO Optimize with memcpy if src_xstep == dest_xstep == 1 */
int x, y;
double* src_row;
double* dest_row;
src += src_ystart * src_ystep + src_xstart * src_xstep;
dest += dest_ystart * dest_ystep + dest_xstart * dest_xstep;
for (y = 0; y < ysize; y++)
{
src_row = src;
dest_row = dest;
for (x = 0; x < xsize; x++)
{
*dest = *src;
src += src_xstep;
dest += dest_xstep;
}
src = src_row + src_ystep;
dest = dest_row + dest_ystep;
}
}