00001 
00002 /* Copyright (c) Mark J. Kilgard, 1996. */
00003 
00004 /* This program is freely distributable without licensing fees 
00005    and is provided without guarantee or warrantee expressed or 
00006    implied. This program is -not- in the public domain. */
00007 
00008 /* compile: cc -o glxdino glxdino.c -lGLU -lGL -lXmu -lX11 */
00009 
00010 #include <stdio.h>
00011 #include <stdlib.h>
00012 #include <string.h>
00013 #include <math.h>       /* for cos(), sin(), and sqrt() */
00014 #include <GL/glx.h>     /* this includes X and gl.h headers */
00015 #include <GL/glu.h>     /* gluPerspective(), gluLookAt(), GLU
00016                            polygon * tesselator */
00017 
00018 typedef enum {
00019   RESERVED, BODY_SIDE, BODY_EDGE, BODY_WHOLE, ARM_SIDE, ARM_EDGE, ARM_WHOLE,
00020   LEG_SIDE, LEG_EDGE, LEG_WHOLE, EYE_SIDE, EYE_EDGE, EYE_WHOLE, DINOSAUR
00021 } displayLists;
00022 GLfloat angle = -50;   /* in degrees */
00023 GLboolean doubleBuffer = GL_TRUE, iconic = GL_FALSE, keepAspect = GL_FALSE;
00024 GLdouble bodyWidth = 2.0;
00025 GLfloat body[][2] = { {0, 3}, {1, 1}, {5, 1}, {8, 4}, {10, 4}, {11, 5},
00026   {11, 11.5}, {13, 12}, {13, 13}, {10, 13.5}, {13, 14}, {13, 15}, {11, 16},
00027   {8, 16}, {7, 15}, {7, 13}, {8, 12}, {7, 11}, {6, 6}, {4, 3}, {3, 2},
00028   {1, 2} };
00029 GLfloat arm[][2] = { {8, 10}, {9, 9}, {10, 9}, {13, 8}, {14, 9}, {16, 9},
00030   {15, 9.5}, {16, 10}, {15, 10}, {15.5, 11}, {14.5, 10}, {14, 11}, {14, 10},
00031   {13, 9}, {11, 11}, {9, 11} };
00032 GLfloat leg[][2] = { {8, 6}, {8, 4}, {9, 3}, {9, 2}, {8, 1}, {8, 0.5}, {9, 0},
00033   {12, 0}, {10, 1}, {10, 2}, {12, 4}, {11, 6}, {10, 7}, {9, 7} };
00034 GLfloat eye[][2] = { {8.75, 15}, {9, 14.7}, {9.6, 14.7}, {10.1, 15},
00035   {9.6, 15.25}, {9, 15.25} };
00036 GLfloat lightZeroPosition[] = {10.0, 4.0, 10.0, 1.0};
00037 GLfloat lightZeroColor[] = {0.8, 1.0, 0.8, 1.0}; /* green-tinted */
00038 GLfloat lightOnePosition[] = {-1.0, -2.0, 1.0, 0.0};
00039 GLfloat lightOneColor[] = {0.6, 0.3, 0.2, 1.0};  /* red-tinted */
00040 GLfloat skinColor[] = {0.1, 1.0, 0.1, 1.0}, eyeColor[] = {1.0, 0.2, 0.2, 1.0};
00041 
00042 void
00043 fatalError(char *message)
00044 {
00045   fprintf(stderr, "glxdino: %s\n", message);
00046   exit(1);
00047 }
00048 
00049 /* it seems that some compilers have a new type for the third argument */
00050 /* 03 Aug 2004 [rickr] */
00051 #ifdef LINUX2
00052 #define CAST_GLU_FUNCPTR (_GLUfuncptr)
00053 #else
00054 #define CAST_GLU_FUNCPTR
00055 #endif
00056 
00057 void
00058 extrudeSolidFromPolygon(GLfloat data[][2], unsigned int dataSize,
00059   GLdouble thickness, GLuint side, GLuint edge, GLuint whole)
00060 {
00061   static GLUtriangulatorObj *tobj = NULL;
00062   GLdouble vertex[3], dx, dy, len;
00063   int i;
00064   int count = dataSize / (2 * sizeof(GLfloat));
00065 
00066   if (tobj == NULL) {
00067     tobj = gluNewTess();  /* create and initialize a GLU
00068                              polygon * tesselation object */
00069     gluTessCallback(tobj, GLU_BEGIN, CAST_GLU_FUNCPTR glBegin);
00070     gluTessCallback(tobj, GLU_VERTEX, CAST_GLU_FUNCPTR glVertex2fv);
00071                                                             /* semi-tricky */
00072     gluTessCallback(tobj, GLU_END, CAST_GLU_FUNCPTR glEnd);
00073   }
00074   glNewList(side, GL_COMPILE);
00075   glShadeModel(GL_SMOOTH);  /* smooth minimizes seeing
00076                                tessellation */
00077   gluBeginPolygon(tobj);
00078   for (i = 0; i < count; i++) {
00079     vertex[0] = data[i][0];
00080     vertex[1] = data[i][1];
00081     vertex[2] = 0;
00082     gluTessVertex(tobj, vertex, &data[i]);
00083   }
00084   gluEndPolygon(tobj);
00085   glEndList();
00086   glNewList(edge, GL_COMPILE);
00087   glShadeModel(GL_FLAT);  /* flat shade keeps angular hands
00088                              from being * "smoothed" */
00089   glBegin(GL_QUAD_STRIP);
00090   for (i = 0; i <= count; i++) {
00091     /* mod function handles closing the edge */
00092     glVertex3f(data[i % count][0], data[i % count][1], 0.0);
00093     glVertex3f(data[i % count][0], data[i % count][1], thickness);
00094     /* Calculate a unit normal by dividing by Euclidean
00095        distance. We * could be lazy and use
00096        glEnable(GL_NORMALIZE) so we could pass in * arbitrary
00097        normals for a very slight performance hit. */
00098     dx = data[(i + 1) % count][1] - data[i % count][1];
00099     dy = data[i % count][0] - data[(i + 1) % count][0];
00100     len = sqrt(dx * dx + dy * dy);
00101     glNormal3f(dx / len, dy / len, 0.0);
00102   }
00103   glEnd();
00104   glEndList();
00105   glNewList(whole, GL_COMPILE);
00106   glFrontFace(GL_CW);
00107   glCallList(edge);
00108   glNormal3f(0.0, 0.0, -1.0);  /* constant normal for side */
00109   glCallList(side);
00110   glPushMatrix();
00111   glTranslatef(0.0, 0.0, thickness);
00112   glFrontFace(GL_CCW);
00113   glNormal3f(0.0, 0.0, 1.0);  /* opposite normal for other side
00114                                */
00115   glCallList(side);
00116   glPopMatrix();
00117   glEndList();
00118 }
00119 
00120 void
00121 makeDinosaur(void)
00122 {
00123   GLfloat bodyWidth = 3.0;
00124 
00125   extrudeSolidFromPolygon(body, sizeof(body), bodyWidth,
00126     BODY_SIDE, BODY_EDGE, BODY_WHOLE);
00127   extrudeSolidFromPolygon(arm, sizeof(arm), bodyWidth / 4,
00128     ARM_SIDE, ARM_EDGE, ARM_WHOLE);
00129   extrudeSolidFromPolygon(leg, sizeof(leg), bodyWidth / 2,
00130     LEG_SIDE, LEG_EDGE, LEG_WHOLE);
00131   extrudeSolidFromPolygon(eye, sizeof(eye), bodyWidth + 0.2,
00132     EYE_SIDE, EYE_EDGE, EYE_WHOLE);
00133   glNewList(DINOSAUR, GL_COMPILE);
00134   glMaterialfv(GL_FRONT, GL_DIFFUSE, skinColor);
00135   glCallList(BODY_WHOLE);
00136   glPushMatrix();
00137   glTranslatef(0.0, 0.0, bodyWidth);
00138   glCallList(ARM_WHOLE);
00139   glCallList(LEG_WHOLE);
00140   glTranslatef(0.0, 0.0, -bodyWidth - bodyWidth / 4);
00141   glCallList(ARM_WHOLE);
00142   glTranslatef(0.0, 0.0, -bodyWidth / 4);
00143   glCallList(LEG_WHOLE);
00144   glTranslatef(0.0, 0.0, bodyWidth / 2 - 0.1);
00145   glMaterialfv(GL_FRONT, GL_DIFFUSE, eyeColor);
00146   glCallList(EYE_WHOLE);
00147   glPopMatrix();
00148   glEndList();
00149 }
00150 
00151 void
00152 contextInit(void)
00153 {
00154   glClearColor(0.0, 0.0, 0.0, 1.0);
00155   glEnable(GL_CULL_FACE);  /* ~50% better perfomance than no
00156                               back-face * culling on Entry
00157                               Indigo */
00158   glEnable(GL_DEPTH_TEST);  /* enable depth buffering */
00159   glEnable(GL_LIGHTING);  /* enable lighting */
00160   glMatrixMode(GL_PROJECTION);  /* set up projection transform */
00161   gluPerspective( /* field of view in degree */ 40.0,
00162     /* aspect ratio */ 1.0, /* Z near */ 1.0, /* Z far */ 40.0);
00163   glMatrixMode(GL_MODELVIEW);  /* now change to modelview */
00164   gluLookAt(0.0, 0.0, 30.0,  /* eye is at (0,0,30) */
00165     0.0, 0.0, 0.0,      /* center is at (0,0,0) */
00166     0.0, 1.0, 0.);      /* up is in positive Y direction */
00167   glRotatef(angle, 0.0, 1.0, 0.0);
00168   glTranslatef(-8, -8, -bodyWidth / 2);
00169 
00170   glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, 1);
00171   glLightfv(GL_LIGHT0, GL_POSITION, lightZeroPosition);
00172   glLightfv(GL_LIGHT0, GL_DIFFUSE, lightZeroColor);
00173   glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 0.1);
00174   glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.05);
00175   glLightfv(GL_LIGHT1, GL_POSITION, lightOnePosition);
00176   glLightfv(GL_LIGHT1, GL_DIFFUSE, lightOneColor);
00177   glEnable(GL_LIGHT0);
00178   glEnable(GL_LIGHT1);  /* enable both lights */
00179 }
00180 
00181 void
00182 redraw(void)
00183 {
00184   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
00185   glCallList(DINOSAUR);
00186 }
00187 
00188 int generateEPS(char *filename, int inColor, unsigned int width, unsigned int height);
00189 
00190 int
00191 main(int argc, char **argv)
00192 {
00193   static int configuration[] = { GLX_DOUBLEBUFFER, GLX_RGBA, GLX_DEPTH_SIZE, 16,
00194     GLX_RED_SIZE, 1, GLX_GREEN_SIZE, 1, GLX_BLUE_SIZE, 1, None};
00195   Display *dpy;
00196   XVisualInfo *vi;
00197   GLXContext cx;
00198   Pixmap pmap;
00199   GLXPixmap glxpmap;
00200   int imageWidth = 400, imageHeight = 400;
00201 
00202   dpy = XOpenDisplay(NULL);
00203   if (dpy == NULL)
00204     fatalError("could not open display");
00205 
00206   if (!glXQueryExtension(dpy, NULL, NULL))
00207     fatalError("X server has no OpenGL GLX extension");
00208 
00209   /* find an OpenGL-capable RGB visual with depth buffer */
00210   vi = glXChooseVisual(dpy, DefaultScreen(dpy), &configuration[1]);
00211   if (vi == NULL) {
00212     vi = glXChooseVisual(dpy, DefaultScreen(dpy), &configuration[0]);
00213     if (vi == NULL) {
00214       fatalError("no appropriate RGB visual with depth buffer");
00215     }
00216   }
00217   /* create an OpenGL rendering context */
00218   cx = glXCreateContext(dpy, vi,
00219     NULL,               /* no sharing of display lists */
00220     False);             /* direct rendering if possible */
00221   if (cx == NULL)
00222     fatalError("could not create rendering context");
00223 
00224   pmap = XCreatePixmap(dpy, RootWindow(dpy, vi->screen),
00225     imageWidth, imageHeight, vi->depth);
00226   glxpmap = glXCreateGLXPixmap(dpy, vi, pmap);
00227   glXMakeCurrent(dpy, glxpmap, cx);
00228 
00229   contextInit();
00230   makeDinosaur();
00231   glViewport(0, 0, imageWidth, imageHeight);
00232   redraw();
00233 
00234   generateEPS("dino.rgb.eps", /* color */ 1, imageWidth, imageHeight);
00235   generateEPS("dino.bw.eps", /* black&white */ 0, imageWidth, imageHeight);
00236   exit(0) ;
00237 }
00238 
00239 GLvoid *grabPixels(int inColor, unsigned int width, unsigned int height);
00240 
00241 int
00242 generateEPS(char *filename, int inColor, unsigned int width, unsigned int height)
00243 {
00244   FILE *fp;
00245   GLvoid *pixels;
00246   unsigned char *curpix;
00247   int components, pos, i;
00248 
00249   pixels = grabPixels(inColor, width, height);
00250   if (pixels == NULL)
00251     return 1;
00252   if (inColor)
00253     components = 3;     /* Red, green, blue. */
00254   else
00255     components = 1;     /* Luminance. */
00256 
00257   fp = fopen(filename, "w");
00258   if (fp == NULL) {
00259     return 2;
00260   }
00261   fprintf(fp, "%%!PS-Adobe-2.0 EPSF-1.2\n");
00262   fprintf(fp, "%%%%Creator: OpenGL pixmap render output\n");
00263   fprintf(fp, "%%%%BoundingBox: 0 0 %d %d\n", width, height);
00264   fprintf(fp, "%%%%EndComments\n");
00265   fprintf(fp, "gsave\n");
00266   fprintf(fp, "/bwproc {\n");
00267   fprintf(fp, "    rgbproc\n");
00268   fprintf(fp, "    dup length 3 idiv string 0 3 0\n");
00269   fprintf(fp, "    5 -1 roll {\n");
00270   fprintf(fp, "    add 2 1 roll 1 sub dup 0 eq\n");
00271   fprintf(fp, "    { pop 3 idiv 3 -1 roll dup 4 -1 roll dup\n");
00272   fprintf(fp, "        3 1 roll 5 -1 roll put 1 add 3 0 }\n");
00273   fprintf(fp, "    { 2 1 roll } ifelse\n");
00274   fprintf(fp, "    } forall\n");
00275   fprintf(fp, "    pop pop pop\n");
00276   fprintf(fp, "} def\n");
00277   fprintf(fp, "systemdict /colorimage known not {\n");
00278   fprintf(fp, "    /colorimage {\n");
00279   fprintf(fp, "        pop\n");
00280   fprintf(fp, "        pop\n");
00281   fprintf(fp, "        /rgbproc exch def\n");
00282   fprintf(fp, "        { bwproc } image\n");
00283   fprintf(fp, "    } def\n");
00284   fprintf(fp, "} if\n");
00285   fprintf(fp, "/picstr %d string def\n", width * components);
00286   fprintf(fp, "%d %d scale\n", width, height);
00287   fprintf(fp, "%d %d %d\n", width, height, 8);
00288   fprintf(fp, "[%d 0 0 %d 0 0]\n", width, height);
00289   fprintf(fp, "{currentfile picstr readhexstring pop}\n");
00290   fprintf(fp, "false %d\n", components);
00291   fprintf(fp, "colorimage\n");
00292 
00293   curpix = (unsigned char *) pixels;
00294   pos = 0;
00295   for (i = width * height * components; i > 0; i--) {
00296     fprintf(fp, "%02hx", *curpix++);
00297     if (++pos >= 32) {
00298       fprintf(fp, "\n");
00299       pos = 0;
00300     }
00301   }
00302   if (pos)
00303     fprintf(fp, "\n");
00304 
00305   fprintf(fp, "grestore\n");
00306   free(pixels);
00307   fclose(fp);
00308   return 0;
00309 }
00310 
00311 GLvoid *
00312 grabPixels(int inColor, unsigned int width, unsigned int height)
00313 {
00314   GLvoid *buffer;
00315   GLint swapbytes, lsbfirst, rowlength;
00316   GLint skiprows, skippixels, alignment;
00317   GLenum format;
00318   unsigned int size;
00319 
00320   if (inColor) {
00321     format = GL_RGB;
00322     size = width * height * 3;
00323   } else {
00324     format = GL_LUMINANCE;
00325     size = width * height * 1;
00326   }
00327 
00328   buffer = (GLvoid *) malloc(size);
00329   if (buffer == NULL)
00330     return NULL;
00331 
00332   /* Save current modes. */
00333   glGetIntegerv(GL_PACK_SWAP_BYTES, &swapbytes);
00334   glGetIntegerv(GL_PACK_LSB_FIRST, &lsbfirst);
00335   glGetIntegerv(GL_PACK_ROW_LENGTH, &rowlength);
00336   glGetIntegerv(GL_PACK_SKIP_ROWS, &skiprows);
00337   glGetIntegerv(GL_PACK_SKIP_PIXELS, &skippixels);
00338   glGetIntegerv(GL_PACK_ALIGNMENT, &alignment);
00339   /* Little endian machines (DEC Alpha for example) could
00340      benefit from setting GL_PACK_LSB_FIRST to GL_TRUE
00341      instead of GL_FALSE, but this would require changing the
00342      generated bitmaps too. */
00343   glPixelStorei(GL_PACK_SWAP_BYTES, GL_FALSE);
00344   glPixelStorei(GL_PACK_LSB_FIRST, GL_FALSE);
00345   glPixelStorei(GL_PACK_ROW_LENGTH, 0);
00346   glPixelStorei(GL_PACK_SKIP_ROWS, 0);
00347   glPixelStorei(GL_PACK_SKIP_PIXELS, 0);
00348   glPixelStorei(GL_PACK_ALIGNMENT, 1);
00349 
00350   /* Actually read the pixels. */
00351   glReadPixels(0, 0, width, height, format,
00352     GL_UNSIGNED_BYTE, (GLvoid *) buffer);
00353 
00354   /* Restore saved modes. */
00355   glPixelStorei(GL_PACK_SWAP_BYTES, swapbytes);
00356   glPixelStorei(GL_PACK_LSB_FIRST, lsbfirst);
00357   glPixelStorei(GL_PACK_ROW_LENGTH, rowlength);
00358   glPixelStorei(GL_PACK_SKIP_ROWS, skiprows);
00359   glPixelStorei(GL_PACK_SKIP_PIXELS, skippixels);
00360   glPixelStorei(GL_PACK_ALIGNMENT, alignment);
00361   return buffer;
00362 }