/*
* warp.c
* David Blythe, 1997
*
* An example of warping a mesh to produce a morphing effect.
*
*/
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <GL/glut.h>
#include "texture.h"
static unsigned *image;
static int width, height, components;
static float incr = .01, dir = 1.0;
static float scale = 1.0, tscale = 1.0, trotx, troty;
static float transx = 1.0, transy, rotx, roty;
static int ox = -1, oy = -1;
static int mot = 0;
float *wrotx = &rotx, *wroty = &roty, *wscale = &scale;
#define PAN 1
#define ROT 2
void
pan(const int x, const int y) {
transx += (x-ox)/5.;
transy -= (y-oy)/5.;
ox = x; oy = y;
glutPostRedisplay();
}
void
rotate(const int x, const int y) {
*wrotx += x-ox;
if (*wrotx > 360.) *wrotx -= 360.;
else if (*wrotx < -360.) *wrotx += 360.;
*wroty += y-oy;
if (*wroty > 360.) *wroty -= 360.;
else if (*wroty < -360.) *wroty += 360.;
ox = x; oy = y;
glutPostRedisplay();
}
void
motion(int x, int y) {
if (mot == PAN) pan(x, y);
else if (mot == ROT) rotate(x,y);
}
void
mouse(int button, int state, int x, int y) {
if(state == GLUT_DOWN) {
switch(button) {
case GLUT_LEFT_BUTTON:
mot = PAN;
motion(ox = x, oy = y);
break;
case GLUT_MIDDLE_BUTTON:
mot = ROT;
motion(ox = x, oy = y);
break;
case GLUT_RIGHT_BUTTON:
break;
}
} else if (state == GLUT_UP) {
mot = 0;
}
}
#define MAXMESH 64
float Ml[4*2*(MAXMESH+1)*2 * (MAXMESH+1)];
float N = 1.5;
float B = -1.5;
void
mesh1(float x0, float x1, float y0, float y1,
float s0, float s1, float t0, float t1, float z, int nx, int ny)
{
float y,x,s,t,dx,dy,ds,dt,vb[3],tb[2];
float v;
float *mp = Ml;
dx = (x1-x0)/nx;
dy = (y1-y0)/ny;
ds = (s1-s0)/nx;
dt = (t1-t0)/ny;
y = y0;
t = t0;
vb[2] = z;
while (y < y1) {
x = x0;
s = s0;
while(x <= x1) {
tb[0] = s; tb[1] = t;
vb[0] = x; vb[1] = y;
v = N*N - x*x - y*y;
if (v < 0.0) v = 0.0;
vb[2] = sqrt(v) + B;
if (vb[2] < 0.) vb[2] = 0.0;
*mp++ = tb[0];
*mp++ = tb[1];
mp += 2;
*mp++ = vb[0];
*mp++ = vb[1];
*mp++ = vb[2];
mp++;
tb[1] = t+dt;
vb[1] = y+dy;
v = N*N - x*x - (y+dy)*(y+dy);
if (v < 0.0) v = 0.0;
vb[2] = sqrt(v) + B;
if (vb[2] < 0.) vb[2] = 0.0;
*mp++ = tb[0];
*mp++ = tb[1];
mp += 2;
*mp++ = vb[0];
*mp++ = vb[1];
*mp++ = vb[2];
mp++;
x += dx;
s += ds;
}
y += dy;
t += dt;
}
}
void
drawmesh(int nx,int ny) {
float *mp = Ml;
int i,j;
glColor4f(1,1,1,1);
for (i = ny+1; i; i--) {
glBegin(GL_TRIANGLE_STRIP);
for (j = nx+1; j; j--) {
glTexCoord2fv(mp);
glVertex3fv(mp+4);
glTexCoord2fv(mp+8);
glVertex3fv(mp+12); mp += 16;
}
glEnd();
}
}
void
move(void) {
if (N > 2.1 || N < 1.5)
dir = -dir;
N += incr*dir;
mesh1(-1.5,1.5,-1.5,1.5,0.0,1.0,0.0,1.0,0.0,64,64);
glutPostRedisplay();
}
void
alphaup(void) {
incr += .01;
if (incr > .1) incr = .1;
glutPostRedisplay();
}
void
alphadown(void) {
incr -= .01;
if (incr < 0) incr = 0;
glutPostRedisplay();
}
void
left(void) {
*wscale -= .1;
}
void
right(void) {
*wscale += .1;
}
void
wire(void) {
static int wire_mode;
if (wire_mode ^= 1)
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
else
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
}
void
tfunc(void) {
static state;
if (state ^= 1) {
wrotx = &trotx;
wroty = &troty;
wscale = &tscale;
} else {
wrotx = &rotx;
wroty = &roty;
wscale = &scale;
}
}
void
help(void) {
printf("'h' - help\n");
printf("'w' - wire frame\n");
printf("UP - faster\n");
printf("DOWN - slower\n");
}
void
init(char *filename) {
if (filename) {
image = read_texture(filename, &width, &height, &components);
if (image == NULL) {
fprintf(stderr, "Error: Can't load image file \"%s\".\n",
filename);
exit(EXIT_FAILURE);
} else {
printf("%d x %d image loaded\n", width, height);
}
if (components < 3 || components > 4) {
printf("must be RGB or RGBA image\n");
exit(EXIT_FAILURE);
}
} else {
int i, j;
components = 4; width = height = 128;
image = (unsigned *) malloc(width*height*sizeof(unsigned));
for (j = 0; j < height; j++)
for (i = 0; i < width; i++) {
if (i & 16)
image[i+j*width] = 0xff;
else
image[i+j*width] = 0xff00;
if (j&16)
image[i+j*width] |= 0xff0000;
}
}
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, components, width,
height, 0, GL_RGBA, GL_UNSIGNED_BYTE,
image);
glEnable(GL_TEXTURE_2D);
glMatrixMode(GL_TEXTURE);
glLoadIdentity();
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(90.,1.,.1,10.);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.,0.,-1.5);
glClearColor(.25, .25, .25, 0.);
}
void
display(void) {
glClear(GL_COLOR_BUFFER_BIT);
glMatrixMode(GL_TEXTURE);
glPushMatrix();
glTranslatef(.5f, .5f, .5f);
glRotatef(trotx, 0.f, 0.f, 1.f);
glScalef(tscale, tscale, tscale);
glTranslatef(-.5f, -.5f, -.5f);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glRotatef(rotx, 0.f, 0.f, 1.f);
glScalef(scale, scale, scale);
drawmesh(64,64);
glPopMatrix();
glMatrixMode(GL_TEXTURE);
glPopMatrix();
glMatrixMode(GL_MODELVIEW);
glutSwapBuffers();
}
void
reshape(int w, int h) {
glViewport(0, 0, w, h);
}
/*ARGSUSED1*/
void
key(unsigned char key, int x, int y) {
switch(key) {
case '\033': exit(0); break;
case 'h': help(); break;
case 't': tfunc(); break;
case 'w': wire(); break;
}
}
/*ARGSUSED1*/
void
special(int key, int x, int y) {
switch(key) {
case GLUT_KEY_UP: alphaup(); break;
case GLUT_KEY_DOWN: alphadown(); break;
case GLUT_KEY_LEFT: left(); break;
case GLUT_KEY_RIGHT:right(); break;
}
}
void
visible(int state)
{
if (state == GLUT_VISIBLE)
glutIdleFunc(move);
else
glutIdleFunc(0);
}
int
main(int argc, char** argv) {
glutInitDisplayMode(GLUT_RGBA|GLUT_DOUBLE);
glutInitWindowSize(512, 512);
glutInit(&argc, argv);
glutCreateWindow("warp");
init(argc == 1 ? "data/fendi.rgb" : argv[1]);
glutKeyboardFunc(key);
glutSpecialFunc(special);
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutIdleFunc(move);
glutMouseFunc(mouse);
glutMotionFunc(motion);
glutVisibilityFunc(visible);
glutMainLoop();
return 0;
}