/*
* texture.c
*
* FUNCTION:
* texture mapping hack
*
* HISTORY:
* Created by Linas Vepstas April 1994
* Reaction-Diffusion added Dec 1996
* Copyright (c) 1994, 1996, Linas Vepstas <linas@linas.org>
*/
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include "texture.h"
Texture * current_texture = 0x0;
Texture * planet_texture = 0x0;
Texture * check_texture = 0x0;
Texture * barberpole_texture = 0x0;
Texture * wild_tooth_texture = 0x0;
Texture * reaction_texture = 0x0;
void (*texanim)(int) = 0x0;
void (*reaction_texanim)(int) = 0x0;
/* ======================================================= */
#define TEXTURE_SIZE 256
static Texture *
create_planet_texture (void)
{
int i, j;
Texture * tex;
unsigned char * pixmap;
pixmap = (unsigned char *) malloc (TEXTURE_SIZE*TEXTURE_SIZE*3*sizeof (unsigned char));
for (i=0; i< TEXTURE_SIZE; i++) {
for (j=0; j< TEXTURE_SIZE; j++) {
int mi = i - TEXTURE_SIZE/2;
int mj = j - TEXTURE_SIZE/2;
pixmap [3*TEXTURE_SIZE*i + 3*j] = 100*mi*mi + (40*mj*mj >> 8);
pixmap [3*TEXTURE_SIZE*i + 3*j + 1] = (10*mi*mi + 4*mj*mj) ;
pixmap [3*TEXTURE_SIZE*i + 3*j + 2] = (1000*mi*mi + 400*mj*mj) >> 16 ;
}
}
tex = (Texture *) malloc (sizeof (Texture));
tex -> size = TEXTURE_SIZE;
tex -> pixmap = pixmap;
return tex;
}
/* ======================================================= */
static Texture *
create_check_texture (void)
{
int i, j;
Texture * tex;
unsigned char * pixmap;
pixmap = (unsigned char *) malloc (TEXTURE_SIZE*TEXTURE_SIZE*3*sizeof (unsigned char));
for (i=0; i< TEXTURE_SIZE; i++) {
for (j=0; j< TEXTURE_SIZE; j++) {
pixmap [3*TEXTURE_SIZE*i + 3*j] =
255 * ( (((i)/32) %2) == (((j)/32) %2));
pixmap [3*TEXTURE_SIZE*i + 3*j + 1] =
255 * ( (((i)/32) %2) == (((j)/32) %2));
pixmap [3*TEXTURE_SIZE*i + 3*j + 2] =
255 * ( (((i)/32) %2) == (((j)/32) %2));
}
}
tex = (Texture *) malloc (sizeof (Texture));
tex -> size = TEXTURE_SIZE;
tex -> pixmap = pixmap;
return tex;
}
/* ======================================================= */
static Texture *
create_barberpole_texture (void)
{
int i, j;
Texture * tex;
unsigned char * pixmap;
pixmap = (unsigned char *) malloc (TEXTURE_SIZE*TEXTURE_SIZE*3*sizeof (unsigned char));
for (i=0; i< TEXTURE_SIZE; i++) {
for (j=0; j< TEXTURE_SIZE; j++) {
pixmap [3*TEXTURE_SIZE*i + 3*j] = 255 * (((i+j)/32) %2);
pixmap [3*TEXTURE_SIZE*i + 3*j + 1] = 255 * (((i+j)/32) %2);
pixmap [3*TEXTURE_SIZE*i + 3*j + 2] = 255 * (((i+j)/32) %2);
}
}
tex = (Texture *) malloc (sizeof (Texture));
tex -> size = TEXTURE_SIZE;
tex -> pixmap = pixmap;
return tex;
}
/* ======================================================= */
static Texture *
create_wild_tooth_texture (void)
{
int i, j;
Texture * tex;
unsigned char * pixmap;
pixmap = (unsigned char *) malloc (TEXTURE_SIZE*TEXTURE_SIZE*3*sizeof (unsigned char));
for (i=0; i< TEXTURE_SIZE; i++) {
for (j=0; j< TEXTURE_SIZE; j++) {
pixmap [3*TEXTURE_SIZE*i + 3*j] =
255 * ( (((i+j)/32) %2) == (((i-j)/32) %2));
pixmap [3*TEXTURE_SIZE*i + 3*j + 1] =
255 * ( (((i+j)/32) %2) == (((i-j)/32) %2));
pixmap [3*TEXTURE_SIZE*i + 3*j + 2] =
255 * ( (((i+j)/32) %2) == (((i-j)/32) %2));
}
}
tex = (Texture *) malloc (sizeof (Texture));
tex -> size = TEXTURE_SIZE;
tex -> pixmap = pixmap;
return tex;
}
/* ======================================================= */
/* reaction-diffusion textures, witkin & kass, siggraph 1991 */
/* this is a quick and dirty, sloppy, non-cpu-efficient
* non-parametric-corrected isotropic impelemtation. */
static float CPfield[TEXTURE_SIZE][TEXTURE_SIZE];
static float CMfield[TEXTURE_SIZE][TEXTURE_SIZE];
static float RPfield[TEXTURE_SIZE][TEXTURE_SIZE];
static float RMfield[TEXTURE_SIZE][TEXTURE_SIZE];
static float tmpfield[TEXTURE_SIZE][TEXTURE_SIZE];
int niter=0;
static Texture *
create_reaction_texture (void)
{
int i,j;
Texture * tex;
unsigned char * pixmap;
pixmap = (unsigned char *)
malloc (TEXTURE_SIZE*TEXTURE_SIZE*3* sizeof (unsigned char));
for (i=0; i< TEXTURE_SIZE; i++) {
for (j=0; j<TEXTURE_SIZE; j++) {
CPfield[i][j] = ((float) ((i*j)%4096)) / 4096.0;
CMfield[i][j] = ((float) ((i*i+j*j)%8192)) / 8192.0;
RPfield[i][j] = 0.0;
RMfield[i][j] = 0.0;
}
}
for (i=0; i< TEXTURE_SIZE; i++) {
for (j=0; j<TEXTURE_SIZE; j++) {
pixmap [3*TEXTURE_SIZE*i+3*j] = 255.0 * CPfield[i][j];
pixmap [3*TEXTURE_SIZE*i+3*j+1] = 127.0 * (CPfield[i][j]+CMfield[i][j]);
pixmap [3*TEXTURE_SIZE*i+3*j+2] = 255.0 * CMfield[i][j];
}
}
tex = (Texture *) malloc (sizeof (Texture));
tex -> size = TEXTURE_SIZE;
tex -> pixmap = pixmap;
reaction_texture = tex;
return tex;
}
static float delta_t = 0.1;
static float h = 1.0;
static float ap = 1.0;
static float am = 0.5;
static float b = 0.0;
static float r = 0.5;
static void
iterate_reaction_texture (int reset)
{
int i,j, im1, ip1, jm1, jp1;
int iter;
char * pixmap;
float tmp;
float cpmax, cpmin, cmmax, cmmin, cps, cms;
float cpr, cmr;
niter ++;
printf ("diffusion-reaction iteration %d \n", niter);
cpmax = -1.0e50;
cpmin = +1.0e50;
cmmax = -1.0e50;
cmmin = +1.0e50;
if (reset) {
niter = 0;
for (i=0; i< TEXTURE_SIZE; i++) {
for (j=0; j<TEXTURE_SIZE; j++) {
CPfield[i][j] = ((float) ((i*j)%4096)) / 4096.0;
CMfield[i][j] = ((float) ((i*i+j*j)%8192)) / 8192.0;
RPfield[i][j] = 0.0;
RMfield[i][j] = 0.0;
}
}
} else {
for (iter=0; iter<1; iter ++) {
/* reaction-diffusion */
for (i=0; i< TEXTURE_SIZE; i++) {
im1 = (i+TEXTURE_SIZE-1)%TEXTURE_SIZE;
ip1 = (i+1)%TEXTURE_SIZE;
for (j=0; j<TEXTURE_SIZE; j++) {
jm1 = (j+TEXTURE_SIZE-1)%TEXTURE_SIZE;
jp1 = (j+1)%TEXTURE_SIZE;
tmp = CPfield[im1][j];
tmp += CPfield[ip1][j];
tmp += CPfield[i][jm1];
tmp += CPfield[i][jp1];
tmp -= 4.0 * CPfield[i][j];
tmp *= ap*ap / (h*h);
tmp -= b* CPfield[i][j];
tmp += RPfield[i][j];
tmpfield[i][j] = tmp;
}
}
for (i=0; i< TEXTURE_SIZE; i++) {
for (j=0; j<TEXTURE_SIZE; j++) {
CPfield[i][j] += delta_t * tmpfield[i][j];
if (cpmax < CPfield[i][j]) cpmax = CPfield[i][j];
if (cpmin > CPfield[i][j]) cpmin = CPfield[i][j];
}
}
for (i=0; i< TEXTURE_SIZE; i++) {
im1 = (i+TEXTURE_SIZE-1)%TEXTURE_SIZE;
ip1 = (i+1)%TEXTURE_SIZE;
for (j=0; j<TEXTURE_SIZE; j++) {
jm1 = (j+TEXTURE_SIZE-1)%TEXTURE_SIZE;
jp1 = (j+1)%TEXTURE_SIZE;
tmp = CMfield[im1][j];
tmp += CMfield[ip1][j];
tmp += CMfield[i][jm1];
tmp += CMfield[i][jp1];
tmp -= 4.0 * CMfield[i][j];
tmp *= am*am / (h*h);
tmp -= b* CMfield[i][j];
tmp += RMfield[i][j];
tmpfield[i][j] = tmp;
}
}
for (i=0; i< TEXTURE_SIZE; i++) {
for (j=0; j<TEXTURE_SIZE; j++) {
CMfield[i][j] += delta_t * tmpfield[i][j];
if (cmmax < CMfield[i][j]) cmmax = CMfield[i][j];
if (cmmin > CMfield[i][j]) cmmin = CMfield[i][j];
}
}
for (i=0; i< TEXTURE_SIZE; i++) {
for (j=0; j<TEXTURE_SIZE; j++) {
if ( CPfield[i][j] > CMfield[i][j]) {
RPfield[i][j] = r;
RMfield[i][j] = r;
} else {
RPfield[i][j] = 0.0;
RMfield[i][j] = 0.0;
}
}
}
}
}
pixmap = reaction_texture -> pixmap;
cps = 1.0 / (cpmax-cpmin);
cms = 1.0 / (cmmax-cmmin);
for (i=0; i< TEXTURE_SIZE; i++) {
for (j=0; j<TEXTURE_SIZE; j++) {
cpr = cps * (CPfield[i][j]-cpmin);
cmr = cms * (CMfield[i][j]-cmmin);
cpr = CPfield[i][j];
cmr = CMfield[i][j];
pixmap [3*TEXTURE_SIZE*i+3*j] = 255.0 * cpr;
pixmap [3*TEXTURE_SIZE*i+3*j+1] = 70.0 * (cpr+cmr);
pixmap [3*TEXTURE_SIZE*i+3*j+2] = 130.0 * cmr;
}
}
}
/* ======================================================= */
void setup_textures (void) {
planet_texture = create_planet_texture ();
check_texture = create_check_texture ();
barberpole_texture = create_barberpole_texture ();
wild_tooth_texture = create_wild_tooth_texture ();
reaction_texture = create_reaction_texture ();
reaction_texanim = iterate_reaction_texture;
current_texture = wild_tooth_texture;
current_texture = check_texture;
}
/* ================== END OF FILE ========================= */
