Добавил:
Studfiles2
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Лабораторная работа №32 / LabDlg
.cpp/*
* billboard.c
* David Blythe, 1997
*
* An example of billboarding. A billboard is an object that always
* faces toward the eye.
*
*/
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <GL/glut.h>
#include "texture.h"
#ifdef _WIN32
#define sinf(x) ((float)sin((x)))
#define cosf(x) ((float)cos((x)))
#define atan2f(x, y) ((float)atan2((x), (y)))
#define M_PI 3.14159265
#endif
static int billboard = 1, texture = 1;
static float scale = 1.;
static float transx = 1.0, transy, rotx, roty;
static int ox = -1, oy = -1;
static int mot = 0;
#define PAN 1
#define ROT 2
void
pan(const int x, const int y) {
transx += (x-ox)/500.;
transy -= (y-oy)/500.;
ox = x; oy = y;
glutPostRedisplay();
}
void
rotate(const int x, const int y) {
rotx += x-ox;
if (rotx > 360.) rotx -= 360.;
else if (rotx < -360.) rotx += 360.;
roty += y-oy;
if (roty > 360.) roty -= 360.;
else if (roty < -360.) roty += 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:
break;
case GLUT_RIGHT_BUTTON:
mot = ROT;
motion(ox = x, oy = y);
break;
}
} else if (state == GLUT_UP) {
mot = 0;
}
}
void afunc(void) {
static int state;
if (state ^= 1) {
glAlphaFunc(GL_GREATER, .01);
glEnable(GL_ALPHA_TEST);
} else {
glDisable(GL_ALPHA_TEST);
}
}
void demofunc(void) {
static float deltax = -.03;
static float deltay = 2.;
transx += deltax;
if (transx > 2.0 || transx < -2.0) deltax = -deltax;
rotx += deltay;
if (rotx > 360.f || rotx < 0.f) deltay = -deltay;
glutPostRedisplay();
}
void dfunc(void) {
static int demo;
if (demo ^= 1) {
glutIdleFunc(demofunc);
} else {
glutIdleFunc(0);
}
}
void bfunc(void) {
static int state;
if (state ^= 1) {
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
} else {
glDisable(GL_BLEND);
}
}
void ffunc(void) {
billboard ^= 1;
}
void tfunc(void) {
texture ^= 1;
}
void up(void) { scale += .1; }
void down(void) { scale -= .1; }
void help(void) {
printf("Usage: billboard [image]\n");
printf("'h' - help\n");
printf("'a' - toggle alpha test\n");
printf("'b' - toggle blend\n");
printf("'d' - toggle demo mode\n");
printf("'f' - toggle fixed mode\n");
printf("'t' - toggle texturing\n");
printf("'UP' - scale up\n");
printf("'DOWN' - scale down\n");
printf("left mouse - pan\n");
printf("right mouse - rotate\n");
}
void init(char *filename) {
static unsigned *image;
static int width, height, components;
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 != 4) {
printf("must be an RGBA image\n");
exit(EXIT_FAILURE);
}
} else {
int i, j;
unsigned char *img;
components = 4; width = height = 256;
image = (unsigned *) malloc(width*height*sizeof(unsigned));
img = (unsigned char *)image;
for (j = 0; j < height; j++)
for (i = 0; i < width; i++) {
int w2 = width/2, h2 = height/2;
if ((i & 32) ^ (j & 32)) {
img[4*(i+j*width)+0] = 0xff;
img[4*(i+j*width)+1] = 0xff;
img[4*(i+j*width)+2] = 0xff;
} else {
img[4*(i+j*width)+0] = 0x0;
img[4*(i+j*width)+1] = 0x0;
img[4*(i+j*width)+2] = 0x0;
}
if ((i-w2)*(i-w2) + (j-h2)*(j-h2) > 64*64 &&
(i-w2)*(i-w2) + (j-h2)*(j-h2) < 300*300) img[4*(i+j*width)+3] = 0xff;
}
}
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
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_PROJECTION);
glLoadIdentity();
gluPerspective(50.,1.,.1,10.);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.,0.,-5.5);
glClearColor(.25f, .25f, .25f, .25f);
glEnable(GL_DEPTH_TEST);
}
static void calcMatrix(void);
#define RAD(x) (((x)*M_PI)/180.)
void display(void) {
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
gluLookAt(-sinf(RAD(rotx))*5.5,transy,cosf(RAD(rotx))*5.5, 0.,0.,0., 0.,1.,0.);
/* floor */
glDisable(GL_TEXTURE_2D);
glColor4f(0.2, 0.8, 0.2, 1.);
glBegin(GL_POLYGON);
glVertex3f(-2.0, -1.0, -2.0);
glVertex3f( 2.0, -1.0, -2.0);
glVertex3f( 2.0, -1.0, 2.0);
glVertex3f(-2.0, -1.0, 2.0);
glEnd();
glPushMatrix();
glTranslatef(0.f, 0.f, -transx);
if (billboard) calcMatrix();
glScalef(scale,scale,1.);
if (texture) glEnable(GL_TEXTURE_2D);
glColor4f(1.f, 1.f, 1.f, 1.f);
glBegin(GL_POLYGON);
glTexCoord2f(0.0, 0.0);
glVertex2f(-1.0, -1.0);
glTexCoord2f(1.0, 0.0);
glVertex2f(1.0, -1.0);
glTexCoord2f(1.0, 1.0);
glVertex2f(1.0, 1.0);
glTexCoord2f(0.0, 1.0);
glVertex2f(-1.0, 1.0);
glEnd();
glPopMatrix();
glutSwapBuffers();
}
void reshape(int w, int h) {
glViewport(0, 0, w, h);
}
/*ARGSUSED*/
void
key(unsigned char key, int x, int y) {
switch(key) {
case 'a': afunc(); break;
case 'd': dfunc(); break;
case 'b': bfunc(); break;
case 'f': ffunc(); break;
case 't': tfunc(); break;
case 'h': help(); break;
case '\033': exit(EXIT_SUCCESS); break;
default: break;
}
glutPostRedisplay();
}
/*ARGSUSED*/
void
special(int key, int x, int y) {
switch(key) {
case GLUT_KEY_UP: up(); break;
case GLUT_KEY_DOWN: down(); break;
}
glutPostRedisplay();
}
int main(int argc, char** argv) {
glutInitDisplayMode(GLUT_RGBA|GLUT_DOUBLE|GLUT_DEPTH);
glutInitWindowSize(512, 512);
glutInit(&argc, argv);
glutCreateWindow("billboard");
glutDisplayFunc(display);
glutKeyboardFunc(key);
glutSpecialFunc(special);
glutReshapeFunc(reshape);
glutMouseFunc(mouse);
glutMotionFunc(motion);
init(argv[1]);
glutMainLoop();
return 0;
}
void
buildRot(float theta, float x, float y, float z, float m[16]) {
float d = x*x + y*y + z*z;
float ct = cosf(RAD(theta)), st = sinf(RAD(theta));
/* normalize */
if (d > 0) {
d = 1/d;
x *= d;
y *= d;
z *= d;
}
m[ 0] = 1; m[ 1] = 0; m[ 2] = 0; m[ 3] = 0;
m[ 4] = 0; m[ 5] = 1; m[ 6] = 0; m[ 7] = 0;
m[ 8] = 0; m[ 9] = 0; m[10] = 1; m[11] = 0;
m[12] = 0; m[13] = 0; m[14] = 0; m[15] = 1;
/* R = uu' + cos(theta)*(I-uu') + sin(theta)*S
*
* S = 0 -z y u' = (x, y, z)
* z 0 -x
* -y x 0
*/
m[0] = x*x + ct*(1-x*x) + st*0;
m[4] = x*y + ct*(0-x*y) + st*-z;
m[8] = x*z + ct*(0-x*z) + st*y;
m[1] = y*x + ct*(0-y*x) + st*z;
m[5] = y*y + ct*(1-y*y) + st*0;
m[9] = y*z + ct*(0-y*z) + st*-x;
m[2] = z*x + ct*(0-z*x) + st*-y;
m[6] = z*y + ct*(0-z*y) + st*x;
m[10]= z*z + ct*(1-z*z) + st*0;
}
static void
calcMatrix(void) {
float mat[16];
glGetFloatv(GL_MODELVIEW_MATRIX, mat);
buildRot(-180*atan2f(mat[8], mat[10])/M_PI, 0, 1, 0, mat);
glMultMatrixf(mat);
}
Соседние файлы в папке Лабораторная работа №32