proj_plot

annotate main.cc @ 0:e467998dcc64

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initial commit
author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 24 Jan 2015 16:36:34 +0200
parents
children 64483c640a38
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@0 12 void draw_label(const Vector2 &pos, const char *fmt, ...);
nuclear@0 13 void reshape(int x, int y);
nuclear@0 14 void keyb(unsigned char key, int x, int y);
nuclear@0 15 void keyb_up(unsigned char key, int x, int y);
nuclear@0 16 void mouse(int bn, int st, int x, int y);
nuclear@0 17 void motion(int x, int y);
nuclear@0 18 Vector2 screen_to_world(int x, int y);
nuclear@0 19
nuclear@0 20 int win_xsz, win_ysz;
nuclear@0 21 float aspect;
nuclear@0 22
nuclear@0 23 Matrix4x4 proj;
nuclear@0 24 Vector2 cur_point;
nuclear@0 25 bool cur_point_valid;
nuclear@0 26
nuclear@0 27 bool keystate[256];
nuclear@0 28 dtx_font *font;
nuclear@0 29 float pan[2], zoom = 1.0;
nuclear@0 30
nuclear@0 31 int main(int argc, char **argv)
nuclear@0 32 {
nuclear@0 33 glutInit(&argc, argv);
nuclear@0 34 glutInitWindowSize(1024, 768);
nuclear@0 35 glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_MULTISAMPLE);
nuclear@0 36 glutCreateWindow("Interactive projection diagram");
nuclear@0 37
nuclear@0 38 glutDisplayFunc(display);
nuclear@0 39 glutReshapeFunc(reshape);
nuclear@0 40 glutKeyboardFunc(keyb);
nuclear@0 41 glutKeyboardUpFunc(keyb_up);
nuclear@0 42 glutMouseFunc(mouse);
nuclear@0 43 glutMotionFunc(motion);
nuclear@0 44
nuclear@0 45 if(!init()) {
nuclear@0 46 return 1;
nuclear@0 47 }
nuclear@0 48
nuclear@0 49 glutMainLoop();
nuclear@0 50 return 0;
nuclear@0 51 }
nuclear@0 52
nuclear@0 53 bool init()
nuclear@0 54 {
nuclear@0 55 if(!(font = dtx_open_font("data/font.ttf", 16))) {
nuclear@0 56 fprintf(stderr, "failed to open font\n");
nuclear@0 57 return false;
nuclear@0 58 }
nuclear@0 59
nuclear@0 60 glEnable(GL_MULTISAMPLE);
nuclear@0 61 proj.set_perspective(DEG_TO_RAD(60), 1, 0.5, 500.0);
nuclear@0 62 return true;
nuclear@0 63 }
nuclear@0 64
nuclear@0 65 void display()
nuclear@0 66 {
nuclear@0 67 glClear(GL_COLOR_BUFFER_BIT);
nuclear@0 68
nuclear@0 69 glMatrixMode(GL_MODELVIEW);
nuclear@0 70 glLoadIdentity();
nuclear@0 71 glTranslatef(-pan[0], -pan[1], 0);
nuclear@0 72 glScalef(zoom, zoom, zoom);
nuclear@0 73
nuclear@0 74 draw_grid();
nuclear@0 75
nuclear@0 76 if(cur_point_valid) {
nuclear@0 77 glPointSize(7.0);
nuclear@0 78 glBegin(GL_POINTS);
nuclear@0 79 glColor3f(0.2, 1, 0.2);
nuclear@0 80 glVertex2f(cur_point.x, cur_point.y);
nuclear@0 81 glEnd();
nuclear@0 82
nuclear@0 83 glColor3f(0.15, 0.5, 0.15);
nuclear@0 84 draw_label(cur_point, "(%.2f, %.2f)", cur_point.x, cur_point.y);
nuclear@0 85 }
nuclear@0 86
nuclear@0 87 glutSwapBuffers();
nuclear@0 88 assert(glGetError() == GL_NO_ERROR);
nuclear@0 89 }
nuclear@0 90
nuclear@0 91 #define LINE(x0, y0, x1, y1) (glVertex2f(x0, y0), glVertex2f(x1, y1))
nuclear@0 92
nuclear@0 93 void draw_grid()
nuclear@0 94 {
nuclear@0 95 float ymin = -1;
nuclear@0 96 float ymax = 1;
nuclear@0 97 float xmin = -1;
nuclear@0 98 float xmax = 1;
nuclear@0 99 float ticksz = 0.015;
nuclear@0 100
nuclear@0 101 glBegin(GL_LINES);
nuclear@0 102 glColor3f(1, 1, 1);
nuclear@0 103 LINE(0, -1, 0, 1);
nuclear@0 104 LINE(-1, 0, 1, 0);
nuclear@0 105
nuclear@0 106 for(int i=1; i<11; i++) {
nuclear@0 107 for(int j=0; j<2; j++) {
nuclear@0 108 float x = (float)i / 10.0 * (j ? -1.0 : 1.0);
nuclear@0 109
nuclear@0 110 glColor3f(0.15, 0.15, 0.15);
nuclear@0 111 LINE(x, ymin, x, ymax);
nuclear@0 112 LINE(xmin, x, xmax, x);
nuclear@0 113
nuclear@0 114 glColor3f(0.4, 0.4, 0.4);
nuclear@0 115 LINE(x, -ticksz, x, ticksz);
nuclear@0 116 LINE(-ticksz, x, ticksz, x);
nuclear@0 117 }
nuclear@0 118 }
nuclear@0 119 glEnd();
nuclear@0 120 }
nuclear@0 121
nuclear@0 122 void draw_label(const Vector2 &pos, const char *fmt, ...)
nuclear@0 123 {
nuclear@0 124 static char buf[512];
nuclear@0 125 va_list ap;
nuclear@0 126
nuclear@0 127 va_start(ap, fmt);
nuclear@0 128 vsnprintf(buf, sizeof buf - 1, fmt, ap);
nuclear@0 129 va_end(ap);
nuclear@0 130
nuclear@0 131 glPushMatrix();
nuclear@0 132 glTranslatef(pos.x + 0.01, pos.y + 0.01, 0);
nuclear@0 133 float s = 2.0 / (win_ysz * zoom);
nuclear@0 134 glScalef(s, s, s);
nuclear@0 135
nuclear@0 136 dtx_string(buf);
nuclear@0 137
nuclear@0 138 glPopMatrix();
nuclear@0 139 }
nuclear@0 140
nuclear@0 141 void reshape(int x, int y)
nuclear@0 142 {
nuclear@0 143 win_xsz = x;
nuclear@0 144 win_ysz = y;
nuclear@0 145 aspect = (float)x / (float)y;
nuclear@0 146
nuclear@0 147 glViewport(0, 0, x, y);
nuclear@0 148
nuclear@0 149 glMatrixMode(GL_PROJECTION);
nuclear@0 150 glLoadIdentity();
nuclear@0 151 glScalef(1.0 / aspect, 1.0, 1.0);
nuclear@0 152 }
nuclear@0 153
nuclear@0 154 void keyb(unsigned char key, int x, int y)
nuclear@0 155 {
nuclear@0 156 keystate[key] = 1;
nuclear@0 157
nuclear@0 158 switch(key) {
nuclear@0 159 case 27:
nuclear@0 160 exit(0);
nuclear@0 161 }
nuclear@0 162 }
nuclear@0 163
nuclear@0 164 void keyb_up(unsigned char key, int x, int y)
nuclear@0 165 {
nuclear@0 166 keystate[key] = 0;
nuclear@0 167 }
nuclear@0 168
nuclear@0 169 bool bnstate[16];
nuclear@0 170 int prev_x, prev_y;
nuclear@0 171
nuclear@0 172 void mouse(int bn, int st, int x, int y)
nuclear@0 173 {
nuclear@0 174 bnstate[bn - GLUT_LEFT_BUTTON] = st == GLUT_DOWN;
nuclear@0 175 prev_x = x;
nuclear@0 176 prev_y = y;
nuclear@0 177
nuclear@0 178 if(bn == GLUT_LEFT_BUTTON && st == GLUT_DOWN) {
nuclear@0 179 cur_point = screen_to_world(x, y);
nuclear@0 180 cur_point_valid = true;
nuclear@0 181 glutPostRedisplay();
nuclear@0 182 }
nuclear@0 183 }
nuclear@0 184
nuclear@0 185 void motion(int x, int y)
nuclear@0 186 {
nuclear@0 187 float dx = 2.0 * aspect * (x - prev_x) / (float)win_xsz;
nuclear@0 188 float dy = 2.0 * (y - prev_y) / (float)win_ysz;
nuclear@0 189 prev_x = x;
nuclear@0 190 prev_y = y;
nuclear@0 191
nuclear@0 192 if(bnstate[0]) {
nuclear@0 193 cur_point = screen_to_world(x, y);
nuclear@0 194 glutPostRedisplay();
nuclear@0 195 }
nuclear@0 196 if(bnstate[1]) {
nuclear@0 197 pan[0] -= dx;
nuclear@0 198 pan[1] += dy;
nuclear@0 199
nuclear@0 200 glutPostRedisplay();
nuclear@0 201 }
nuclear@0 202 if(bnstate[2]) {
nuclear@0 203 zoom += dy;
nuclear@0 204
nuclear@0 205 if(zoom < 1e-4) zoom = 1e-4;
nuclear@0 206 glutPostRedisplay();
nuclear@0 207 }
nuclear@0 208 }
nuclear@0 209
nuclear@0 210 Vector2 screen_to_world(int px, int py)
nuclear@0 211 {
nuclear@0 212 float sx = 2.0 * aspect * (1.0 / zoom) / (float)win_xsz;
nuclear@0 213 float sy = 2.0 * (1.0 / zoom) / (float)win_ysz;
nuclear@0 214
nuclear@0 215 float x = (float)px * sx - (aspect + pan[0]) / zoom;
nuclear@0 216 float y = (float)(win_ysz - py) * sy - (1.0 + pan[1]) / zoom;
nuclear@0 217
nuclear@0 218 return Vector2(x, y);
nuclear@0 219 }