proj_plot

annotate main.cc @ 2:e6ed6acee42f

find changesets by author, revision, files, or words in the commit message
more foo
author John Tsiombikas <nuclear@member.fsf.org>
date Sun, 25 Jan 2015 01:59:28 +0200
parents 64483c640a38
children
rev   line source
nuclear@0 1 #include <stdio.h>
nuclear@0 2 #include <stdlib.h>
nuclear@0 3 #include <stdarg.h>
nuclear@0 4 #include <assert.h>
nuclear@0 5 #include <GL/glut.h>
nuclear@0 6 #include <vmath/vmath.h>
nuclear@0 7 #include <drawtext.h>
nuclear@0 8
nuclear@0 9 bool init();
nuclear@0 10 void display();
nuclear@0 11 void draw_grid();
nuclear@1 12 void draw_frustum();
nuclear@0 13 void draw_label(const Vector2 &pos, const char *fmt, ...);
nuclear@0 14 void reshape(int x, int y);
nuclear@0 15 void keyb(unsigned char key, int x, int y);
nuclear@0 16 void keyb_up(unsigned char key, int x, int y);
nuclear@0 17 void mouse(int bn, int st, int x, int y);
nuclear@0 18 void motion(int x, int y);
nuclear@0 19 Vector2 screen_to_world(int x, int y);
nuclear@1 20 Vector2 project(const Vector2 &v);
nuclear@1 21 Vector2 unproject(const Vector2 &v);
nuclear@2 22 float calc_proj_dist(float fov);
nuclear@0 23
nuclear@0 24 int win_xsz, win_ysz;
nuclear@0 25 float aspect;
nuclear@0 26
nuclear@0 27 Matrix4x4 proj;
nuclear@2 28 float proj_offset;
nuclear@0 29 Vector2 cur_point;
nuclear@0 30 bool cur_point_valid;
nuclear@0 31
nuclear@1 32 float proj_near = 0.5, proj_far = 50.0;
nuclear@2 33 float proj_vfov = 60.0;
nuclear@1 34
nuclear@0 35 bool keystate[256];
nuclear@2 36 bool bnstate[16];
nuclear@2 37 int prev_x, prev_y;
nuclear@2 38 unsigned int modkeys;
nuclear@2 39
nuclear@0 40 dtx_font *font;
nuclear@2 41 float pan[2] = {0, 0.85}, zoom = 0.3;
nuclear@2 42 float snap_dist = 0.25;
nuclear@0 43
nuclear@0 44 int main(int argc, char **argv)
nuclear@0 45 {
nuclear@0 46 glutInit(&argc, argv);
nuclear@0 47 glutInitWindowSize(1024, 768);
nuclear@0 48 glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_MULTISAMPLE);
nuclear@0 49 glutCreateWindow("Interactive projection diagram");
nuclear@0 50
nuclear@0 51 glutDisplayFunc(display);
nuclear@0 52 glutReshapeFunc(reshape);
nuclear@0 53 glutKeyboardFunc(keyb);
nuclear@0 54 glutKeyboardUpFunc(keyb_up);
nuclear@0 55 glutMouseFunc(mouse);
nuclear@0 56 glutMotionFunc(motion);
nuclear@0 57
nuclear@0 58 if(!init()) {
nuclear@0 59 return 1;
nuclear@0 60 }
nuclear@0 61
nuclear@0 62 glutMainLoop();
nuclear@0 63 return 0;
nuclear@0 64 }
nuclear@0 65
nuclear@0 66 bool init()
nuclear@0 67 {
nuclear@0 68 if(!(font = dtx_open_font("data/font.ttf", 16))) {
nuclear@0 69 fprintf(stderr, "failed to open font\n");
nuclear@0 70 return false;
nuclear@0 71 }
nuclear@0 72
nuclear@0 73 glEnable(GL_MULTISAMPLE);
nuclear@1 74 proj.set_perspective(DEG_TO_RAD(proj_vfov), 1, 1.0, 50.0);
nuclear@2 75 proj.translate(Vector3(proj_offset, 0, 0));
nuclear@0 76 return true;
nuclear@0 77 }
nuclear@0 78
nuclear@0 79 void display()
nuclear@0 80 {
nuclear@0 81 glClear(GL_COLOR_BUFFER_BIT);
nuclear@0 82
nuclear@0 83 glMatrixMode(GL_MODELVIEW);
nuclear@0 84 glLoadIdentity();
nuclear@0 85 glTranslatef(-pan[0], -pan[1], 0);
nuclear@0 86 glScalef(zoom, zoom, zoom);
nuclear@0 87
nuclear@0 88 draw_grid();
nuclear@0 89
nuclear@1 90 draw_frustum();
nuclear@1 91
nuclear@0 92 if(cur_point_valid) {
nuclear@1 93 Vector2 ppt = project(cur_point);
nuclear@1 94
nuclear@0 95 glPointSize(7.0);
nuclear@0 96 glBegin(GL_POINTS);
nuclear@0 97 glColor3f(0.2, 1, 0.2);
nuclear@0 98 glVertex2f(cur_point.x, cur_point.y);
nuclear@1 99 glColor3f(0.7, 0.2, 0.2);
nuclear@1 100 glVertex2f(ppt.x, ppt.y);
nuclear@0 101 glEnd();
nuclear@0 102
nuclear@1 103 glEnable(GL_LINE_STIPPLE);
nuclear@1 104 glLineStipple(4, 0xe0e0);
nuclear@1 105
nuclear@1 106 glBegin(GL_LINES);
nuclear@1 107 glColor3f(0.2, 0.5, 0.2);
nuclear@1 108 glVertex2f(cur_point.x, cur_point.y);
nuclear@1 109 glColor3f(0.5, 0.2, 0.2);
nuclear@1 110 glVertex2f(ppt.x, ppt.y);
nuclear@1 111 glEnd();
nuclear@1 112 glDisable(GL_LINE_STIPPLE);
nuclear@1 113
nuclear@2 114 glColor3f(0.2, 0.5, 0.2);
nuclear@0 115 draw_label(cur_point, "(%.2f, %.2f)", cur_point.x, cur_point.y);
nuclear@2 116 glColor3f(0.5, 0.2, 0.2);
nuclear@1 117 draw_label(ppt, "(%.2f, %.2f)", ppt.x, ppt.y);
nuclear@0 118 }
nuclear@0 119
nuclear@0 120 glutSwapBuffers();
nuclear@0 121 assert(glGetError() == GL_NO_ERROR);
nuclear@0 122 }
nuclear@0 123
nuclear@0 124 #define LINE(x0, y0, x1, y1) (glVertex2f(x0, y0), glVertex2f(x1, y1))
nuclear@0 125
nuclear@0 126 void draw_grid()
nuclear@0 127 {
nuclear@1 128 float ymin = -10;
nuclear@1 129 float ymax = 10;
nuclear@1 130 float xmin = -10;
nuclear@1 131 float xmax = 10;
nuclear@1 132 float ticksz = 0.015 / zoom;
nuclear@0 133
nuclear@0 134 glBegin(GL_LINES);
nuclear@0 135 glColor3f(1, 1, 1);
nuclear@1 136 LINE(0, -10, 0, 10);
nuclear@1 137 LINE(-10, 0, 10, 0);
nuclear@0 138
nuclear@0 139 for(int i=1; i<11; i++) {
nuclear@0 140 for(int j=0; j<2; j++) {
nuclear@1 141 float x = 10.0 * (float)i / 10.0 * (j ? -1.0 : 1.0);
nuclear@0 142
nuclear@0 143 glColor3f(0.15, 0.15, 0.15);
nuclear@0 144 LINE(x, ymin, x, ymax);
nuclear@0 145 LINE(xmin, x, xmax, x);
nuclear@0 146
nuclear@0 147 glColor3f(0.4, 0.4, 0.4);
nuclear@0 148 LINE(x, -ticksz, x, ticksz);
nuclear@0 149 LINE(-ticksz, x, ticksz, x);
nuclear@0 150 }
nuclear@0 151 }
nuclear@0 152 glEnd();
nuclear@0 153 }
nuclear@0 154
nuclear@1 155 void draw_frustum()
nuclear@1 156 {
nuclear@2 157 Vector2 left[2], right[2];
nuclear@1 158
nuclear@1 159 glBegin(GL_LINES);
nuclear@1 160 glColor3f(0.2, 0.4, 0.8);
nuclear@1 161
nuclear@2 162 right[0] = unproject(Vector2(1, 0));
nuclear@2 163 right[1] = unproject(Vector2(1, 1));
nuclear@2 164 LINE(right[0].x, right[0].y, right[1].x, right[1].y);
nuclear@1 165
nuclear@2 166 left[0] = unproject(Vector2(-1, 0));
nuclear@2 167 left[1] = unproject(Vector2(-1, 1));
nuclear@2 168 LINE(left[0].x, left[0].y, left[1].x, left[1].y);
nuclear@1 169
nuclear@2 170 float dist = calc_proj_dist(proj_vfov);
nuclear@2 171 LINE(-1, dist, 1, dist);
nuclear@2 172 glEnd();
nuclear@1 173
nuclear@2 174 /* find the points where the frustum lines hit zero */
nuclear@2 175 glEnable(GL_LINE_STIPPLE);
nuclear@2 176 glLineStipple(3, 0x0101);
nuclear@2 177
nuclear@2 178 glBegin(GL_LINES);
nuclear@2 179 for(int i=0; i<2; i++) {
nuclear@2 180 Vector2 *v = i ? left : right;
nuclear@2 181 float t = -v[1].y / (v[0].y - v[1].y);
nuclear@2 182 float x = v[1].x + (v[0].x - v[1].x) * t;
nuclear@2 183 LINE(v[0].x, v[0].y, x, 0);
nuclear@2 184 }
nuclear@1 185 glEnd();
nuclear@2 186 glDisable(GL_LINE_STIPPLE);
nuclear@1 187 }
nuclear@1 188
nuclear@0 189 void draw_label(const Vector2 &pos, const char *fmt, ...)
nuclear@0 190 {
nuclear@0 191 static char buf[512];
nuclear@0 192 va_list ap;
nuclear@0 193
nuclear@0 194 va_start(ap, fmt);
nuclear@0 195 vsnprintf(buf, sizeof buf - 1, fmt, ap);
nuclear@0 196 va_end(ap);
nuclear@0 197
nuclear@0 198 glPushMatrix();
nuclear@0 199 glTranslatef(pos.x + 0.01, pos.y + 0.01, 0);
nuclear@0 200 float s = 2.0 / (win_ysz * zoom);
nuclear@0 201 glScalef(s, s, s);
nuclear@0 202
nuclear@0 203 dtx_string(buf);
nuclear@0 204
nuclear@0 205 glPopMatrix();
nuclear@0 206 }
nuclear@0 207
nuclear@0 208 void reshape(int x, int y)
nuclear@0 209 {
nuclear@0 210 win_xsz = x;
nuclear@0 211 win_ysz = y;
nuclear@0 212 aspect = (float)x / (float)y;
nuclear@0 213
nuclear@0 214 glViewport(0, 0, x, y);
nuclear@0 215
nuclear@0 216 glMatrixMode(GL_PROJECTION);
nuclear@0 217 glLoadIdentity();
nuclear@0 218 glScalef(1.0 / aspect, 1.0, 1.0);
nuclear@0 219 }
nuclear@0 220
nuclear@0 221 void keyb(unsigned char key, int x, int y)
nuclear@0 222 {
nuclear@0 223 keystate[key] = 1;
nuclear@2 224 modkeys = glutGetModifiers();
nuclear@0 225
nuclear@0 226 switch(key) {
nuclear@0 227 case 27:
nuclear@0 228 exit(0);
nuclear@0 229 }
nuclear@0 230 }
nuclear@0 231
nuclear@0 232 void keyb_up(unsigned char key, int x, int y)
nuclear@0 233 {
nuclear@0 234 keystate[key] = 0;
nuclear@2 235 modkeys = glutGetModifiers();
nuclear@0 236 }
nuclear@0 237
nuclear@0 238 void mouse(int bn, int st, int x, int y)
nuclear@0 239 {
nuclear@0 240 bnstate[bn - GLUT_LEFT_BUTTON] = st == GLUT_DOWN;
nuclear@0 241 prev_x = x;
nuclear@0 242 prev_y = y;
nuclear@2 243 modkeys = glutGetModifiers();
nuclear@0 244
nuclear@0 245 if(bn == GLUT_LEFT_BUTTON && st == GLUT_DOWN) {
nuclear@0 246 cur_point = screen_to_world(x, y);
nuclear@0 247 cur_point_valid = true;
nuclear@0 248 glutPostRedisplay();
nuclear@0 249 }
nuclear@0 250 }
nuclear@0 251
nuclear@0 252 void motion(int x, int y)
nuclear@0 253 {
nuclear@0 254 float dx = 2.0 * aspect * (x - prev_x) / (float)win_xsz;
nuclear@0 255 float dy = 2.0 * (y - prev_y) / (float)win_ysz;
nuclear@0 256 prev_x = x;
nuclear@0 257 prev_y = y;
nuclear@0 258
nuclear@0 259 if(bnstate[0]) {
nuclear@0 260 cur_point = screen_to_world(x, y);
nuclear@2 261 if(keystate['s'] || keystate['S']) {
nuclear@2 262 cur_point.x = round(cur_point.x / snap_dist) * snap_dist;
nuclear@2 263 cur_point.y = round(cur_point.y / snap_dist) * snap_dist;
nuclear@2 264 }
nuclear@0 265 glutPostRedisplay();
nuclear@0 266 }
nuclear@0 267 if(bnstate[1]) {
nuclear@0 268 pan[0] -= dx;
nuclear@0 269 pan[1] += dy;
nuclear@0 270
nuclear@0 271 glutPostRedisplay();
nuclear@0 272 }
nuclear@0 273 if(bnstate[2]) {
nuclear@0 274 zoom += dy;
nuclear@0 275
nuclear@0 276 if(zoom < 1e-4) zoom = 1e-4;
nuclear@0 277 glutPostRedisplay();
nuclear@0 278 }
nuclear@0 279 }
nuclear@0 280
nuclear@0 281 Vector2 screen_to_world(int px, int py)
nuclear@0 282 {
nuclear@1 283 /* canonical [-1, 1] system */
nuclear@1 284 float x = aspect * ((float)px * 2.0 / (float)win_xsz - 1.0);
nuclear@1 285 float y = (float)(win_ysz - py) * 2.0 / (float)win_ysz - 1.0;
nuclear@0 286
nuclear@1 287 /* account for pan & zoom */
nuclear@1 288 x = (x + pan[0]) / zoom;
nuclear@1 289 y = (y + pan[1]) / zoom;
nuclear@0 290
nuclear@0 291 return Vector2(x, y);
nuclear@0 292 }
nuclear@1 293
nuclear@1 294 Vector2 project(const Vector2 &v)
nuclear@1 295 {
nuclear@1 296 Vector4 ppt = Vector4(v.x, 0, -v.y, 1).transformed(proj);
nuclear@2 297 return Vector2(ppt.x / ppt.w, calc_proj_dist(proj_vfov));
nuclear@1 298 }
nuclear@1 299
nuclear@1 300 Vector2 unproject(const Vector2 &v)
nuclear@1 301 {
nuclear@1 302 Vector4 v4 = Vector4(v.x, 0.0, v.y, 1.0);
nuclear@1 303 Matrix4x4 inv_proj = proj.inverse();
nuclear@1 304
nuclear@1 305 Vector4 res4 = v4.transformed(inv_proj);
nuclear@1 306 return Vector2(res4.x / res4.w, -res4.z / res4.w);
nuclear@1 307 }
nuclear@2 308
nuclear@2 309 float calc_proj_dist(float fov)
nuclear@2 310 {
nuclear@2 311 return 1.0 / tan(DEG_TO_RAD(fov) / 2.0);
nuclear@2 312 }