/* * Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc. * * Permission to use, copy, modify, distribute, and sell this software and * its documentation for any purpose is hereby granted without fee, provided * that (i) the above copyright notices and this permission notice appear in * all copies of the software and related documentation, and (ii) the name of * Silicon Graphics may not be used in any advertising or * publicity relating to the software without the specific, prior written * permission of Silicon Graphics. * * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF * ANY KIND, * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. * * IN NO EVENT SHALL SILICON GRAPHICS BE LIABLE FOR * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE * OF THIS SOFTWARE. */ #include <stdio.h> #include <string.h> #include <stdlib.h> #include <math.h> #include <GL/glut.h> #ifndef PI #define PI 3.141592657 #endif enum { NORMAL = 0, WEIRD = 1 }; enum { STREAK = 0, CIRCLE = 1 }; #define MAXSTARS 400 #define MAXPOS 10000 #define MAXWARP 500 #define MAXANGLES 6000 typedef struct _starRec { GLint type; float x[2], y[2], z[2]; float offsetX, offsetY, offsetR, rotation; } starRec; GLenum doubleBuffer; GLint windW, windH; GLenum flag = NORMAL; GLint starCount = MAXSTARS / 2; float speed = 1.0; GLint nitro = 0; starRec stars[MAXSTARS]; float sinTable[MAXANGLES]; float Sin(float angle) { return (sinTable[(GLint)angle]); } float Cos(float angle) { return (sinTable[((GLint)angle+(MAXANGLES/4))%MAXANGLES]); } void NewStar(GLint n, GLint d) { if (rand()%4 == 0) { stars[n].type = CIRCLE; } else { stars[n].type = STREAK; } stars[n].x[0] = (float)(rand() % MAXPOS - MAXPOS / 2); stars[n].y[0] = (float)(rand() % MAXPOS - MAXPOS / 2); stars[n].z[0] = (float)(rand() % MAXPOS + d); if (rand()%4 == 0 && flag == WEIRD) { stars[n].offsetX = (float)(rand() % 100 - 100 / 2); stars[n].offsetY = (float)(rand() % 100 - 100 / 2); stars[n].offsetR = (float)(rand() % 25 - 25 / 2); } else { stars[n].offsetX = 0.0; stars[n].offsetY = 0.0; stars[n].offsetR = 0.0; } } void RotatePoint(float *x, float *y, float rotation) { float tmpX, tmpY; tmpX = *x * Cos(rotation) - *y * Sin(rotation); tmpY = *y * Cos(rotation) + *x * Sin(rotation); *x = tmpX; *y = tmpY; } void MoveStars(void) { float offset; GLint n; static double t0 = -1.; double t, dt; t = glutGet(GLUT_ELAPSED_TIME) / 1000.; if (t0 < 0.) t0 = t; dt = 85.*(t - t0); t0 = t; offset = speed * 60.0; for (n = 0; n < starCount; n++) { stars[n].x[1] = stars[n].x[0]; stars[n].y[1] = stars[n].y[0]; stars[n].z[1] = stars[n].z[0]; stars[n].x[0] += stars[n].offsetX*dt; stars[n].y[0] += stars[n].offsetY*dt; stars[n].z[0] -= offset*dt; stars[n].rotation += stars[n].offsetR*dt; if (stars[n].rotation > MAXANGLES) { stars[n].rotation = 0.0; } else if (stars[n].rotation < 0.0) { stars[n].rotation += 360.0; } } } GLenum StarPoint(GLint n) { float x0, y0, x1, y1, width; GLint i; x0 = stars[n].x[0] * windW / stars[n].z[0]; y0 = stars[n].y[0] * windH / stars[n].z[0]; RotatePoint(&x0, &y0, stars[n].rotation); x0 += windW / 2.0; y0 += windH / 2.0; if (x0 >= 0.0 && x0 < windW && y0 >= 0.0 && y0 < windH) { if (stars[n].type == STREAK) { x1 = stars[n].x[1] * windW / stars[n].z[1]; y1 = stars[n].y[1] * windH / stars[n].z[1]; RotatePoint(&x1, &y1, stars[n].rotation); x1 += windW / 2.0; y1 += windH / 2.0; glLineWidth(MAXPOS/100.0/stars[n].z[0]+1.0); glColor3f(1.0, (MAXWARP-speed)/MAXWARP, (MAXWARP-speed)/MAXWARP); if (fabs(x0-x1) < 1.0 && fabs(y0-y1) < 1.0) { glBegin(GL_POINTS); glVertex2f(x0, y0); glEnd(); } else { glBegin(GL_LINES); glVertex2f(x0, y0); glVertex2f(x1, y1); glEnd(); } } else { width = MAXPOS / 10.0 / stars[n].z[0] + 1.0; glColor3f(1.0, 0.0, 0.0); glBegin(GL_POLYGON); for (i = 0; i < 8; i++) { float x = x0 + width * Cos((float)i*MAXANGLES/8.0); float y = y0 + width * Sin((float)i*MAXANGLES/8.0); glVertex2f(x, y); }; glEnd(); } return GL_TRUE; } else { return GL_FALSE; } } void ShowStars(void) { GLint n; glClear(GL_COLOR_BUFFER_BIT); for (n = 0; n < starCount; n++) { if (stars[n].z[0] > speed || (stars[n].z[0] > 0.0 && speed < MAXWARP)) { if (StarPoint(n) == GL_FALSE) { NewStar(n, MAXPOS); } } else { NewStar(n, MAXPOS); } } } static void Init(void) { float angle; GLint n; srand((unsigned int) glutGet(GLUT_ELAPSED_TIME) ); for (n = 0; n < MAXSTARS; n++) { NewStar(n, 100); } angle = 0.0; for (n = 0; n < MAXANGLES ; n++) { sinTable[n] = sin(angle); angle += PI / (MAXANGLES / 2.0); } glClearColor(0.0, 0.0, 0.0, 0.0); glDisable(GL_DITHER); } void Reshape(int width, int height) { windW = (GLint)width; windH = (GLint)height; glViewport(0, 0, windW, windH); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(-0.5, windW+0.5, -0.5, windH+0.5); glMatrixMode(GL_MODELVIEW); } static void Key(unsigned char key, int x, int y) { switch (key) { case 27: exit(1); case 32: flag = (flag == NORMAL) ? WEIRD : NORMAL; break; case 't': nitro = 1; break; default: return; } } void Draw(void) { MoveStars(); ShowStars(); if (nitro > 0) { speed = (float)(nitro / 10) + 1.0; if (speed > MAXWARP) { speed = MAXWARP; } if (++nitro > MAXWARP*10) { nitro = -nitro; } } else if (nitro < 0) { nitro++; speed = (float)(-nitro / 10) + 1.0; if (speed > MAXWARP) { speed = MAXWARP; } } glFlush(); if (doubleBuffer) { glutSwapBuffers(); } } static GLenum Args(int argc, char **argv) { GLint i; doubleBuffer = GL_TRUE; for (i = 1; i < argc; i++) { if (strcmp(argv[i], "-sb") == 0) { doubleBuffer = GL_FALSE; } else if (strcmp(argv[i], "-db") == 0) { doubleBuffer = GL_TRUE; } } return GL_TRUE; } #if !defined(GLUTCALLBACK) #define GLUTCALLBACK #endif void GLUTCALLBACK glut_post_redisplay_p(void) { glutPostRedisplay(); } int main(int argc, char **argv) { GLenum type; glutInit(&argc, argv); if (Args(argc, argv) == GL_FALSE) { exit(1); } windW = 300; windH = 300; glutInitWindowPosition(0, 0); glutInitWindowSize( 300, 300); type = GLUT_RGB; type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE; glutInitDisplayMode(type); if (glutCreateWindow("Stars") == GL_FALSE) { exit(1); } Init(); glutReshapeFunc(Reshape); glutKeyboardFunc(Key); glutDisplayFunc(Draw); glutIdleFunc(glut_post_redisplay_p); glutMainLoop(); return 0; }