Pileus Git - grits/blob - examples/sorting/sort.c

   1 #include <gtk/gtk.h>
   2 #include <gtk/gtkgl.h>
   3 #include <gdk/gdkkeysyms.h>
   4 #include <GL/gl.h>
   5 #include <GL/glu.h>
   6 #include <stdlib.h>
   7
   8 typedef struct {
   9         gfloat xyz[3];
  10         gfloat color[4];
  11 } __attribute__ ((packed)) vert_t;
  12
  13 static int sort_cmp(const void *a, const void *b)
  14 {
  15         vert_t *a_verts = (vert_t*)(((gfloat*)a)+2);
  16         vert_t *b_verts = (vert_t*)(((gfloat*)b)+2);
  17         gfloat a_sum = a_verts[0].xyz[2] + a_verts[1].xyz[2] + a_verts[2].xyz[2];
  18         gfloat b_sum = b_verts[0].xyz[2] + b_verts[1].xyz[2] + b_verts[2].xyz[2];
  19         return a_sum == b_sum ? 0 :
  20                a_sum <  b_sum ? 1 : -1;
  21 }
  22
  23 static gfloat *sort_start()
  24 {
  25         int size = 1000000;
  26         gfloat *data = g_new0(gfloat, size);
  27         glFeedbackBuffer(size, GL_3D_COLOR, data);
  28         glRenderMode(GL_FEEDBACK);
  29         g_print("1st = %f\n", data[0]);
  30         return data;
  31 }
  32
  33 static void sort_end(gfloat *data)
  34 {
  35         int vertsize = sizeof(vert_t)/sizeof(gfloat);
  36         int nvals = glRenderMode(GL_RENDER);
  37
  38         /* Set up screen coords */
  39         gint view[4];
  40         glGetIntegerv(GL_VIEWPORT, view);
  41
  42         glMatrixMode(GL_PROJECTION);
  43         glLoadIdentity();
  44         glOrtho(view[0],view[2], view[1],view[3], -10,10);
  45
  46         glMatrixMode(GL_MODELVIEW);
  47         glLoadIdentity();
  48         glDisable(GL_LIGHTING);
  49
  50         /* Sort the vertexes (this only works with all-triangles */
  51         int trisize = 2*sizeof(gfloat) + 3*sizeof(vert_t);
  52         int ntris   = nvals*sizeof(gfloat) / trisize;
  53         g_print("%d, %d, %d\n", sizeof(gfloat), trisize, ntris);
  54         qsort(data, ntris, trisize, sort_cmp);
  55
  56         /* Draw the data */
  57         for (int i = 0; i < nvals;) {
  58                 gfloat token = data[i++];
  59                 if (token == GL_POLYGON_TOKEN) {
  60                         gfloat n = data[i++];
  61                         vert_t *verts = (vert_t*)&data[i];
  62                         i += n*vertsize;
  63                         //g_print("GL_POLYGON_TOKEN: %f\n", n);
  64
  65                         /* Draw triangle */
  66                         glBegin(GL_TRIANGLES);
  67                         for (int j = 0; j < n; j++) {
  68                                 //g_print("\t%f, %f, %f\n",
  69                                 //      verts[j].xyz[0],
  70                                 //      verts[j].xyz[1],
  71                                 //      verts[j].xyz[2]);
  72                                 glColor4fv(verts[j].color);
  73                                 glVertex3fv(verts[j].xyz);
  74                         }
  75                         glEnd();
  76
  77                         /* Draw line */
  78                         glColor4f(1,1,1,1);
  79                         glBegin(GL_LINE_LOOP);
  80                         for (int j = 0; j < n; j++)
  81                                 glVertex3fv(verts[j].xyz);
  82                         glEnd();
  83                 } else {
  84                         g_error("Unknown token: %f\n", token);
  85                 }
  86         }
  87         g_free(data);
  88 }
  89
  90 static gboolean on_expose(GtkWidget *drawing, GdkEventExpose *event, gpointer _)
  91 {
  92         //glClearColor(0.5, 0.5, 1.0, 1.0);
  93         glClearColor(0.0, 0.0, 0.0, 0.0);
  94         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  95
  96         glEnable(GL_BLEND);
  97
  98         /* Blend, but broken sorting */
  99         //glEnable(GL_DEPTH_TEST);
 100         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 101
 102         /* No sorting, just add */
 103         //glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 104         //glBlendFunc(GL_ONE, GL_ONE);
 105
 106         /* Lighting */
 107         float light_ambient[]  = {0.1f, 0.1f, 0.0f, 1.0f};
 108         float light_diffuse[]  = {0.9f, 0.9f, 0.9f, 1.0f};
 109         float light_position[] = {-30.0f, 50.0f, 40.0f, 1.0f};
 110         glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);
 111         glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);
 112         glLightfv(GL_LIGHT0, GL_POSITION, light_position);
 113         glEnable(GL_COLOR_MATERIAL);
 114         glEnable(GL_LIGHTING);
 115         glEnable(GL_LIGHT0);
 116
 117         /* Set up projection */
 118         glMatrixMode(GL_PROJECTION);
 119         glLoadIdentity();
 120         glOrtho(1,-1, -0.7,0.7, -10,10);
 121
 122         /* Draw teapots */
 123         glMatrixMode(GL_MODELVIEW);
 124
 125         gfloat *data = sort_start();
 126         glLoadIdentity();
 127         glTranslatef(0.05, 0.05, -2);
 128         glRotatef(30, 1, -1, -0.2);
 129         glColor4f(1.0, 0.2, 0.2, 0.6);
 130         gdk_gl_draw_teapot(TRUE, 0.5);
 131
 132         glLoadIdentity();
 133         glTranslatef(-0.2, -0.05, -2);
 134         glRotatef(30, 1, -1, -0.2);
 135         glColor4f(0.2, 0.2, 1.0, 0.6);
 136         gdk_gl_draw_teapot(TRUE, 0.5);
 137         sort_end(data);
 138
 139         /* Flush */
 140         GdkGLDrawable *gldrawable = gdk_gl_drawable_get_current();
 141         if (gdk_gl_drawable_is_double_buffered(gldrawable))
 142                 gdk_gl_drawable_swap_buffers(gldrawable);
 143         else
 144                 glFlush();
 145         return FALSE;
 146 }
 147
 148 static gboolean on_configure(GtkWidget *drawing, GdkEventConfigure *event, gpointer _)
 149 {
 150         glViewport(0, 0,
 151                 drawing->allocation.width,
 152                 drawing->allocation.height);
 153         return FALSE;
 154 }
 155
 156 static gboolean on_key_press(GtkWidget *widget, GdkEventKey *event, gpointer _)
 157 {
 158         if (event->keyval == GDK_q)
 159                 gtk_main_quit();
 160         return FALSE;
 161 }
 162
 163 int main(int argc, char **argv)
 164 {
 165         gtk_init(&argc, &argv);
 166
 167         GtkWidget   *window   = gtk_window_new(GTK_WINDOW_TOPLEVEL);
 168         GtkWidget   *drawing  = gtk_drawing_area_new();
 169         GdkGLConfig *glconfig = gdk_gl_config_new_by_mode((GdkGLConfigMode)(
 170                         GDK_GL_MODE_RGBA   | GDK_GL_MODE_DEPTH |
 171                         GDK_GL_MODE_DOUBLE | GDK_GL_MODE_ALPHA));
 172         g_signal_connect(window,  "destroy",         G_CALLBACK(gtk_main_quit), NULL);
 173         g_signal_connect(window,  "key-press-event", G_CALLBACK(on_key_press),  NULL);
 174         g_signal_connect(drawing, "expose-event",    G_CALLBACK(on_expose),     NULL);
 175         g_signal_connect(drawing, "configure-event", G_CALLBACK(on_configure),  NULL);
 176         gtk_widget_set_gl_capability(drawing, glconfig, NULL, TRUE, GDK_GL_RGBA_TYPE);
 177         gtk_container_add(GTK_CONTAINER(window), drawing);
 178         gtk_widget_show_all(window);
 179
 180         /* OpenGL setup */
 181         GdkGLContext  *glcontext  = gtk_widget_get_gl_context(GTK_WIDGET(drawing));
 182         GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable(GTK_WIDGET(drawing));
 183         gdk_gl_drawable_gl_begin(gldrawable, glcontext);
 184
 185         gtk_main();
 186
 187         gdk_gl_drawable_gl_end(gldrawable);
 188 }