proj_plot

annotate main.cc @ 1:64483c640a38

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author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 24 Jan 2015 17:49:35 +0200
parents e467998dcc64
children e6ed6acee42f
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@0 22
nuclear@0 23 int win_xsz, win_ysz;
nuclear@0 24 float aspect;
nuclear@0 25
nuclear@0 26 Matrix4x4 proj;
nuclear@0 27 Vector2 cur_point;
nuclear@0 28 bool cur_point_valid;
nuclear@0 29
nuclear@1 30 float proj_near = 0.5, proj_far = 50.0;
nuclear@1 31 float proj_vfov = 50.0;
nuclear@1 32
nuclear@0 33 bool keystate[256];
nuclear@0 34 dtx_font *font;
nuclear@1 35 float pan[2] = {0, 0.85}, zoom = 0.4;
nuclear@0 36
nuclear@0 37 int main(int argc, char **argv)
nuclear@0 38 {
nuclear@0 39 glutInit(&argc, argv);
nuclear@0 40 glutInitWindowSize(1024, 768);
nuclear@0 41 glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_MULTISAMPLE);
nuclear@0 42 glutCreateWindow("Interactive projection diagram");
nuclear@0 43
nuclear@0 44 glutDisplayFunc(display);
nuclear@0 45 glutReshapeFunc(reshape);
nuclear@0 46 glutKeyboardFunc(keyb);
nuclear@0 47 glutKeyboardUpFunc(keyb_up);
nuclear@0 48 glutMouseFunc(mouse);
nuclear@0 49 glutMotionFunc(motion);
nuclear@0 50
nuclear@0 51 if(!init()) {
nuclear@0 52 return 1;
nuclear@0 53 }
nuclear@0 54
nuclear@0 55 glutMainLoop();
nuclear@0 56 return 0;
nuclear@0 57 }
nuclear@0 58
nuclear@0 59 bool init()
nuclear@0 60 {
nuclear@0 61 if(!(font = dtx_open_font("data/font.ttf", 16))) {
nuclear@0 62 fprintf(stderr, "failed to open font\n");
nuclear@0 63 return false;
nuclear@0 64 }
nuclear@0 65
nuclear@0 66 glEnable(GL_MULTISAMPLE);
nuclear@1 67 proj.set_perspective(DEG_TO_RAD(proj_vfov), 1, 1.0, 50.0);
nuclear@0 68 return true;
nuclear@0 69 }
nuclear@0 70
nuclear@0 71 void display()
nuclear@0 72 {
nuclear@0 73 glClear(GL_COLOR_BUFFER_BIT);
nuclear@0 74
nuclear@0 75 glMatrixMode(GL_MODELVIEW);
nuclear@0 76 glLoadIdentity();
nuclear@0 77 glTranslatef(-pan[0], -pan[1], 0);
nuclear@0 78 glScalef(zoom, zoom, zoom);
nuclear@0 79
nuclear@0 80 draw_grid();
nuclear@0 81
nuclear@1 82 draw_frustum();
nuclear@1 83
nuclear@0 84 if(cur_point_valid) {
nuclear@1 85 Vector2 ppt = project(cur_point);
nuclear@1 86
nuclear@0 87 glPointSize(7.0);
nuclear@0 88 glBegin(GL_POINTS);
nuclear@0 89 glColor3f(0.2, 1, 0.2);
nuclear@0 90 glVertex2f(cur_point.x, cur_point.y);
nuclear@1 91 glColor3f(0.7, 0.2, 0.2);
nuclear@1 92 glVertex2f(ppt.x, ppt.y);
nuclear@0 93 glEnd();
nuclear@0 94
nuclear@1 95 glEnable(GL_LINE_STIPPLE);
nuclear@1 96 glLineStipple(4, 0xe0e0);
nuclear@1 97
nuclear@1 98 glBegin(GL_LINES);
nuclear@1 99 glColor3f(0.2, 0.5, 0.2);
nuclear@1 100 glVertex2f(cur_point.x, cur_point.y);
nuclear@1 101 glColor3f(0.5, 0.2, 0.2);
nuclear@1 102 glVertex2f(ppt.x, ppt.y);
nuclear@1 103 glEnd();
nuclear@1 104 glDisable(GL_LINE_STIPPLE);
nuclear@1 105
nuclear@0 106 glColor3f(0.15, 0.5, 0.15);
nuclear@0 107 draw_label(cur_point, "(%.2f, %.2f)", cur_point.x, cur_point.y);
nuclear@1 108 glColor3f(0.4, 0.1, 0.1);
nuclear@1 109 draw_label(ppt, "(%.2f, %.2f)", ppt.x, ppt.y);
nuclear@0 110 }
nuclear@0 111
nuclear@0 112 glutSwapBuffers();
nuclear@0 113 assert(glGetError() == GL_NO_ERROR);
nuclear@0 114 }
nuclear@0 115
nuclear@0 116 #define LINE(x0, y0, x1, y1) (glVertex2f(x0, y0), glVertex2f(x1, y1))
nuclear@0 117
nuclear@0 118 void draw_grid()
nuclear@0 119 {
nuclear@1 120 float ymin = -10;
nuclear@1 121 float ymax = 10;
nuclear@1 122 float xmin = -10;
nuclear@1 123 float xmax = 10;
nuclear@1 124 float ticksz = 0.015 / zoom;
nuclear@0 125
nuclear@0 126 glBegin(GL_LINES);
nuclear@0 127 glColor3f(1, 1, 1);
nuclear@1 128 LINE(0, -10, 0, 10);
nuclear@1 129 LINE(-10, 0, 10, 0);
nuclear@0 130
nuclear@0 131 for(int i=1; i<11; i++) {
nuclear@0 132 for(int j=0; j<2; j++) {
nuclear@1 133 float x = 10.0 * (float)i / 10.0 * (j ? -1.0 : 1.0);
nuclear@0 134
nuclear@0 135 glColor3f(0.15, 0.15, 0.15);
nuclear@0 136 LINE(x, ymin, x, ymax);
nuclear@0 137 LINE(xmin, x, xmax, x);
nuclear@0 138
nuclear@0 139 glColor3f(0.4, 0.4, 0.4);
nuclear@0 140 LINE(x, -ticksz, x, ticksz);
nuclear@0 141 LINE(-ticksz, x, ticksz, x);
nuclear@0 142 }
nuclear@0 143 }
nuclear@0 144 glEnd();
nuclear@0 145 }
nuclear@0 146
nuclear@1 147 void draw_frustum()
nuclear@1 148 {
nuclear@1 149 Vector2 v0, v1;
nuclear@1 150
nuclear@1 151 glBegin(GL_LINES);
nuclear@1 152 glColor3f(0.2, 0.4, 0.8);
nuclear@1 153
nuclear@1 154 v0 = unproject(Vector2(1, 0));
nuclear@1 155 v1 = unproject(Vector2(1, 1));
nuclear@1 156 LINE(v0.x, v0.y, v1.x, v1.y);
nuclear@1 157
nuclear@1 158 v0 = unproject(Vector2(-1, 0));
nuclear@1 159 v1 = unproject(Vector2(-1, 1));
nuclear@1 160 LINE(v0.x, v0.y, v1.x, v1.y);
nuclear@1 161
nuclear@1 162 LINE(-0.5, proj_near, 0.5, proj_near);
nuclear@1 163
nuclear@1 164 glEnd();
nuclear@1 165 }
nuclear@1 166
nuclear@0 167 void draw_label(const Vector2 &pos, const char *fmt, ...)
nuclear@0 168 {
nuclear@0 169 static char buf[512];
nuclear@0 170 va_list ap;
nuclear@0 171
nuclear@0 172 va_start(ap, fmt);
nuclear@0 173 vsnprintf(buf, sizeof buf - 1, fmt, ap);
nuclear@0 174 va_end(ap);
nuclear@0 175
nuclear@0 176 glPushMatrix();
nuclear@0 177 glTranslatef(pos.x + 0.01, pos.y + 0.01, 0);
nuclear@0 178 float s = 2.0 / (win_ysz * zoom);
nuclear@0 179 glScalef(s, s, s);
nuclear@0 180
nuclear@0 181 dtx_string(buf);
nuclear@0 182
nuclear@0 183 glPopMatrix();
nuclear@0 184 }
nuclear@0 185
nuclear@0 186 void reshape(int x, int y)
nuclear@0 187 {
nuclear@0 188 win_xsz = x;
nuclear@0 189 win_ysz = y;
nuclear@0 190 aspect = (float)x / (float)y;
nuclear@0 191
nuclear@0 192 glViewport(0, 0, x, y);
nuclear@0 193
nuclear@0 194 glMatrixMode(GL_PROJECTION);
nuclear@0 195 glLoadIdentity();
nuclear@0 196 glScalef(1.0 / aspect, 1.0, 1.0);
nuclear@0 197 }
nuclear@0 198
nuclear@0 199 void keyb(unsigned char key, int x, int y)
nuclear@0 200 {
nuclear@0 201 keystate[key] = 1;
nuclear@0 202
nuclear@0 203 switch(key) {
nuclear@0 204 case 27:
nuclear@0 205 exit(0);
nuclear@0 206 }
nuclear@0 207 }
nuclear@0 208
nuclear@0 209 void keyb_up(unsigned char key, int x, int y)
nuclear@0 210 {
nuclear@0 211 keystate[key] = 0;
nuclear@0 212 }
nuclear@0 213
nuclear@0 214 bool bnstate[16];
nuclear@0 215 int prev_x, prev_y;
nuclear@0 216
nuclear@0 217 void mouse(int bn, int st, int x, int y)
nuclear@0 218 {
nuclear@0 219 bnstate[bn - GLUT_LEFT_BUTTON] = st == GLUT_DOWN;
nuclear@0 220 prev_x = x;
nuclear@0 221 prev_y = y;
nuclear@0 222
nuclear@0 223 if(bn == GLUT_LEFT_BUTTON && st == GLUT_DOWN) {
nuclear@0 224 cur_point = screen_to_world(x, y);
nuclear@0 225 cur_point_valid = true;
nuclear@0 226 glutPostRedisplay();
nuclear@0 227 }
nuclear@0 228 }
nuclear@0 229
nuclear@0 230 void motion(int x, int y)
nuclear@0 231 {
nuclear@0 232 float dx = 2.0 * aspect * (x - prev_x) / (float)win_xsz;
nuclear@0 233 float dy = 2.0 * (y - prev_y) / (float)win_ysz;
nuclear@0 234 prev_x = x;
nuclear@0 235 prev_y = y;
nuclear@0 236
nuclear@0 237 if(bnstate[0]) {
nuclear@0 238 cur_point = screen_to_world(x, y);
nuclear@0 239 glutPostRedisplay();
nuclear@0 240 }
nuclear@0 241 if(bnstate[1]) {
nuclear@0 242 pan[0] -= dx;
nuclear@0 243 pan[1] += dy;
nuclear@0 244
nuclear@0 245 glutPostRedisplay();
nuclear@0 246 }
nuclear@0 247 if(bnstate[2]) {
nuclear@0 248 zoom += dy;
nuclear@0 249
nuclear@0 250 if(zoom < 1e-4) zoom = 1e-4;
nuclear@0 251 glutPostRedisplay();
nuclear@0 252 }
nuclear@0 253 }
nuclear@0 254
nuclear@0 255 Vector2 screen_to_world(int px, int py)
nuclear@0 256 {
nuclear@1 257 /* canonical [-1, 1] system */
nuclear@1 258 float x = aspect * ((float)px * 2.0 / (float)win_xsz - 1.0);
nuclear@1 259 float y = (float)(win_ysz - py) * 2.0 / (float)win_ysz - 1.0;
nuclear@0 260
nuclear@1 261 /* account for pan & zoom */
nuclear@1 262 x = (x + pan[0]) / zoom;
nuclear@1 263 y = (y + pan[1]) / zoom;
nuclear@0 264
nuclear@0 265 return Vector2(x, y);
nuclear@0 266 }
nuclear@1 267
nuclear@1 268 Vector2 project(const Vector2 &v)
nuclear@1 269 {
nuclear@1 270 Vector4 ppt = Vector4(v.x, 0, -v.y, 1).transformed(proj);
nuclear@1 271 return Vector2(ppt.x / ppt.w, ppt.z / ppt.w);
nuclear@1 272 }
nuclear@1 273
nuclear@1 274 Vector2 unproject(const Vector2 &v)
nuclear@1 275 {
nuclear@1 276 Vector4 v4 = Vector4(v.x, 0.0, v.y, 1.0);
nuclear@1 277 Matrix4x4 inv_proj = proj.inverse();
nuclear@1 278
nuclear@1 279 Vector4 res4 = v4.transformed(inv_proj);
nuclear@1 280 return Vector2(res4.x / res4.w, -res4.z / res4.w);
nuclear@1 281 }