1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/.hgignore	Sat Jan 24 16:36:34 2015 +0200
     1.3 @@ -0,0 +1,4 @@
     1.4 +\.o$
     1.5 +\.d$
     1.6 +\.swp$
     1.7 +^proj_plot$

     2.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     2.2 +++ b/Makefile	Sat Jan 24 16:36:34 2015 +0200
     2.3 @@ -0,0 +1,13 @@
     2.4 +src = $(wildcard *.cc)
     2.5 +obj = $(src:.cc=.o)
     2.6 +bin = proj_plot
     2.7 +
     2.8 +CXXFLAGS = -pedantic -Wall -g
     2.9 +LDFLAGS = -lGL -lglut -lm -lvmath -ldrawtext
    2.10 +
    2.11 +$(bin): $(obj)
    2.12 +	$(CXX) -o $@ $(obj) $(LDFLAGS)
    2.13 +
    2.14 +.PHONY: clean
    2.15 +clean:
    2.16 +	rm -f $(obj) $(bin)

     3.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     3.2 +++ b/README	Sat Jan 24 16:36:34 2015 +0200
     3.3 @@ -0,0 +1,3 @@
     3.4 +dependencies:
     3.5 +- libvmath: http://code.google.com/p/libvmath/
     3.6 +- libdrawtext: http://nuclear.mutantstargoat.com/sw/libdrawtext

     4.1 Binary file data/font.ttf has changed

     5.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     5.2 +++ b/main.cc	Sat Jan 24 16:36:34 2015 +0200
     5.3 @@ -0,0 +1,219 @@
     5.4 +#include <stdio.h>
     5.5 +#include <stdlib.h>
     5.6 +#include <stdarg.h>
     5.7 +#include <assert.h>
     5.8 +#include <GL/glut.h>
     5.9 +#include <vmath/vmath.h>
    5.10 +#include <drawtext.h>
    5.11 +
    5.12 +bool init();
    5.13 +void display();
    5.14 +void draw_grid();
    5.15 +void draw_label(const Vector2 &pos, const char *fmt, ...);
    5.16 +void reshape(int x, int y);
    5.17 +void keyb(unsigned char key, int x, int y);
    5.18 +void keyb_up(unsigned char key, int x, int y);
    5.19 +void mouse(int bn, int st, int x, int y);
    5.20 +void motion(int x, int y);
    5.21 +Vector2 screen_to_world(int x, int y);
    5.22 +
    5.23 +int win_xsz, win_ysz;
    5.24 +float aspect;
    5.25 +
    5.26 +Matrix4x4 proj;
    5.27 +Vector2 cur_point;
    5.28 +bool cur_point_valid;
    5.29 +
    5.30 +bool keystate[256];
    5.31 +dtx_font *font;
    5.32 +float pan[2], zoom = 1.0;
    5.33 +
    5.34 +int main(int argc, char **argv)
    5.35 +{
    5.36 +	glutInit(&argc, argv);
    5.37 +	glutInitWindowSize(1024, 768);
    5.38 +	glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_MULTISAMPLE);
    5.39 +	glutCreateWindow("Interactive projection diagram");
    5.40 +
    5.41 +	glutDisplayFunc(display);
    5.42 +	glutReshapeFunc(reshape);
    5.43 +	glutKeyboardFunc(keyb);
    5.44 +	glutKeyboardUpFunc(keyb_up);
    5.45 +	glutMouseFunc(mouse);
    5.46 +	glutMotionFunc(motion);
    5.47 +
    5.48 +	if(!init()) {
    5.49 +		return 1;
    5.50 +	}
    5.51 +
    5.52 +	glutMainLoop();
    5.53 +	return 0;
    5.54 +}
    5.55 +
    5.56 +bool init()
    5.57 +{
    5.58 +	if(!(font = dtx_open_font("data/font.ttf", 16))) {
    5.59 +		fprintf(stderr, "failed to open font\n");
    5.60 +		return false;
    5.61 +	}
    5.62 +
    5.63 +	glEnable(GL_MULTISAMPLE);
    5.64 +	proj.set_perspective(DEG_TO_RAD(60), 1, 0.5, 500.0);
    5.65 +	return true;
    5.66 +}
    5.67 +
    5.68 +void display()
    5.69 +{
    5.70 +	glClear(GL_COLOR_BUFFER_BIT);
    5.71 +
    5.72 +	glMatrixMode(GL_MODELVIEW);
    5.73 +	glLoadIdentity();
    5.74 +	glTranslatef(-pan[0], -pan[1], 0);
    5.75 +	glScalef(zoom, zoom, zoom);
    5.76 +
    5.77 +	draw_grid();
    5.78 +
    5.79 +	if(cur_point_valid) {
    5.80 +		glPointSize(7.0);
    5.81 +		glBegin(GL_POINTS);
    5.82 +		glColor3f(0.2, 1, 0.2);
    5.83 +		glVertex2f(cur_point.x, cur_point.y);
    5.84 +		glEnd();
    5.85 +
    5.86 +		glColor3f(0.15, 0.5, 0.15);
    5.87 +		draw_label(cur_point, "(%.2f, %.2f)", cur_point.x, cur_point.y);
    5.88 +	}
    5.89 +
    5.90 +	glutSwapBuffers();
    5.91 +	assert(glGetError() == GL_NO_ERROR);
    5.92 +}
    5.93 +
    5.94 +#define LINE(x0, y0, x1, y1)	(glVertex2f(x0, y0), glVertex2f(x1, y1))
    5.95 +
    5.96 +void draw_grid()
    5.97 +{
    5.98 +	float ymin = -1;
    5.99 +	float ymax = 1;
   5.100 +	float xmin = -1;
   5.101 +	float xmax = 1;
   5.102 +	float ticksz = 0.015;
   5.103 +
   5.104 +	glBegin(GL_LINES);
   5.105 +	glColor3f(1, 1, 1);
   5.106 +	LINE(0, -1, 0, 1);
   5.107 +	LINE(-1, 0, 1, 0);
   5.108 +
   5.109 +	for(int i=1; i<11; i++) {
   5.110 +		for(int j=0; j<2; j++) {
   5.111 +			float x = (float)i / 10.0 * (j ? -1.0 : 1.0);
   5.112 +
   5.113 +			glColor3f(0.15, 0.15, 0.15);
   5.114 +			LINE(x, ymin, x, ymax);
   5.115 +			LINE(xmin, x, xmax, x);
   5.116 +
   5.117 +			glColor3f(0.4, 0.4, 0.4);
   5.118 +			LINE(x, -ticksz, x, ticksz);
   5.119 +			LINE(-ticksz, x, ticksz, x);
   5.120 +		}
   5.121 +	}
   5.122 +	glEnd();
   5.123 +}
   5.124 +
   5.125 +void draw_label(const Vector2 &pos, const char *fmt, ...)
   5.126 +{
   5.127 +	static char buf[512];
   5.128 +	va_list ap;
   5.129 +
   5.130 +	va_start(ap, fmt);
   5.131 +	vsnprintf(buf, sizeof buf - 1, fmt, ap);
   5.132 +	va_end(ap);
   5.133 +
   5.134 +	glPushMatrix();
   5.135 +	glTranslatef(pos.x + 0.01, pos.y + 0.01, 0);
   5.136 +	float s = 2.0 / (win_ysz * zoom);
   5.137 +	glScalef(s, s, s);
   5.138 +
   5.139 +	dtx_string(buf);
   5.140 +
   5.141 +	glPopMatrix();
   5.142 +}
   5.143 +
   5.144 +void reshape(int x, int y)
   5.145 +{
   5.146 +	win_xsz = x;
   5.147 +	win_ysz = y;
   5.148 +	aspect = (float)x / (float)y;
   5.149 +
   5.150 +	glViewport(0, 0, x, y);
   5.151 +
   5.152 +	glMatrixMode(GL_PROJECTION);
   5.153 +	glLoadIdentity();
   5.154 +	glScalef(1.0 / aspect, 1.0, 1.0);
   5.155 +}
   5.156 +
   5.157 +void keyb(unsigned char key, int x, int y)
   5.158 +{
   5.159 +	keystate[key] = 1;
   5.160 +
   5.161 +	switch(key) {
   5.162 +	case 27:
   5.163 +		exit(0);
   5.164 +	}
   5.165 +}
   5.166 +
   5.167 +void keyb_up(unsigned char key, int x, int y)
   5.168 +{
   5.169 +	keystate[key] = 0;
   5.170 +}
   5.171 +
   5.172 +bool bnstate[16];
   5.173 +int prev_x, prev_y;
   5.174 +
   5.175 +void mouse(int bn, int st, int x, int y)
   5.176 +{
   5.177 +	bnstate[bn - GLUT_LEFT_BUTTON] = st == GLUT_DOWN;
   5.178 +	prev_x = x;
   5.179 +	prev_y = y;
   5.180 +
   5.181 +	if(bn == GLUT_LEFT_BUTTON && st == GLUT_DOWN) {
   5.182 +		cur_point = screen_to_world(x, y);
   5.183 +		cur_point_valid = true;
   5.184 +		glutPostRedisplay();
   5.185 +	}
   5.186 +}
   5.187 +
   5.188 +void motion(int x, int y)
   5.189 +{
   5.190 +	float dx = 2.0 * aspect * (x - prev_x) / (float)win_xsz;
   5.191 +	float dy = 2.0 * (y - prev_y) / (float)win_ysz;
   5.192 +	prev_x = x;
   5.193 +	prev_y = y;
   5.194 +
   5.195 +	if(bnstate[0]) {
   5.196 +		cur_point = screen_to_world(x, y);
   5.197 +		glutPostRedisplay();
   5.198 +	}
   5.199 +	if(bnstate[1]) {
   5.200 +		pan[0] -= dx;
   5.201 +		pan[1] += dy;
   5.202 +
   5.203 +		glutPostRedisplay();
   5.204 +	}
   5.205 +	if(bnstate[2]) {
   5.206 +		zoom += dy;
   5.207 +
   5.208 +		if(zoom < 1e-4) zoom = 1e-4;
   5.209 +		glutPostRedisplay();
   5.210 +	}
   5.211 +}
   5.212 +
   5.213 +Vector2 screen_to_world(int px, int py)
   5.214 +{
   5.215 +	float sx = 2.0 * aspect * (1.0 / zoom) / (float)win_xsz;
   5.216 +	float sy = 2.0 * (1.0 / zoom) / (float)win_ysz;
   5.217 +
   5.218 +	float x = (float)px * sx - (aspect + pan[0]) / zoom;
   5.219 +	float y = (float)(win_ysz - py) * sy - (1.0 + pan[1]) / zoom;
   5.220 +
   5.221 +	return Vector2(x, y);
   5.222 +}