1.1 --- a/main.cc	Sat Jan 24 17:49:35 2015 +0200
     1.2 +++ b/main.cc	Sun Jan 25 01:59:28 2015 +0200
     1.3 @@ -19,20 +19,27 @@
     1.4  Vector2 screen_to_world(int x, int y);
     1.5  Vector2 project(const Vector2 &v);
     1.6  Vector2 unproject(const Vector2 &v);
     1.7 +float calc_proj_dist(float fov);
     1.8  
     1.9  int win_xsz, win_ysz;
    1.10  float aspect;
    1.11  
    1.12  Matrix4x4 proj;
    1.13 +float proj_offset;
    1.14  Vector2 cur_point;
    1.15  bool cur_point_valid;
    1.16  
    1.17  float proj_near = 0.5, proj_far = 50.0;
    1.18 -float proj_vfov = 50.0;
    1.19 +float proj_vfov = 60.0;
    1.20  
    1.21  bool keystate[256];
    1.22 +bool bnstate[16];
    1.23 +int prev_x, prev_y;
    1.24 +unsigned int modkeys;
    1.25 +
    1.26  dtx_font *font;
    1.27 -float pan[2] = {0, 0.85}, zoom = 0.4;
    1.28 +float pan[2] = {0, 0.85}, zoom = 0.3;
    1.29 +float snap_dist = 0.25;
    1.30  
    1.31  int main(int argc, char **argv)
    1.32  {
    1.33 @@ -65,6 +72,7 @@
    1.34  
    1.35  	glEnable(GL_MULTISAMPLE);
    1.36  	proj.set_perspective(DEG_TO_RAD(proj_vfov), 1, 1.0, 50.0);
    1.37 +	proj.translate(Vector3(proj_offset, 0, 0));
    1.38  	return true;
    1.39  }
    1.40  
    1.41 @@ -103,9 +111,9 @@
    1.42  		glEnd();
    1.43  		glDisable(GL_LINE_STIPPLE);
    1.44  
    1.45 -		glColor3f(0.15, 0.5, 0.15);
    1.46 +		glColor3f(0.2, 0.5, 0.2);
    1.47  		draw_label(cur_point, "(%.2f, %.2f)", cur_point.x, cur_point.y);
    1.48 -		glColor3f(0.4, 0.1, 0.1);
    1.49 +		glColor3f(0.5, 0.2, 0.2);
    1.50  		draw_label(ppt, "(%.2f, %.2f)", ppt.x, ppt.y);
    1.51  	}
    1.52  
    1.53 @@ -146,22 +154,36 @@
    1.54  
    1.55  void draw_frustum()
    1.56  {
    1.57 -	Vector2 v0, v1;
    1.58 +	Vector2 left[2], right[2];
    1.59  
    1.60  	glBegin(GL_LINES);
    1.61  	glColor3f(0.2, 0.4, 0.8);
    1.62  
    1.63 -	v0 = unproject(Vector2(1, 0));
    1.64 -	v1 = unproject(Vector2(1, 1));
    1.65 -	LINE(v0.x, v0.y, v1.x, v1.y);
    1.66 +	right[0] = unproject(Vector2(1, 0));
    1.67 +	right[1] = unproject(Vector2(1, 1));
    1.68 +	LINE(right[0].x, right[0].y, right[1].x, right[1].y);
    1.69  
    1.70 -	v0 = unproject(Vector2(-1, 0));
    1.71 -	v1 = unproject(Vector2(-1, 1));
    1.72 -	LINE(v0.x, v0.y, v1.x, v1.y);
    1.73 +	left[0] = unproject(Vector2(-1, 0));
    1.74 +	left[1] = unproject(Vector2(-1, 1));
    1.75 +	LINE(left[0].x, left[0].y, left[1].x, left[1].y);
    1.76  
    1.77 -	LINE(-0.5, proj_near, 0.5, proj_near);
    1.78 +	float dist = calc_proj_dist(proj_vfov);
    1.79 +	LINE(-1, dist, 1, dist);
    1.80 +	glEnd();
    1.81  
    1.82 +	/* find the points where the frustum lines hit zero */
    1.83 +	glEnable(GL_LINE_STIPPLE);
    1.84 +	glLineStipple(3, 0x0101);
    1.85 +
    1.86 +	glBegin(GL_LINES);
    1.87 +	for(int i=0; i<2; i++) {
    1.88 +		Vector2 *v = i ? left : right;
    1.89 +		float t = -v[1].y / (v[0].y - v[1].y);
    1.90 +		float x = v[1].x + (v[0].x - v[1].x) * t;
    1.91 +		LINE(v[0].x, v[0].y, x, 0);
    1.92 +	}
    1.93  	glEnd();
    1.94 +	glDisable(GL_LINE_STIPPLE);
    1.95  }
    1.96  
    1.97  void draw_label(const Vector2 &pos, const char *fmt, ...)
    1.98 @@ -199,6 +221,7 @@
    1.99  void keyb(unsigned char key, int x, int y)
   1.100  {
   1.101  	keystate[key] = 1;
   1.102 +	modkeys = glutGetModifiers();
   1.103  
   1.104  	switch(key) {
   1.105  	case 27:
   1.106 @@ -209,16 +232,15 @@
   1.107  void keyb_up(unsigned char key, int x, int y)
   1.108  {
   1.109  	keystate[key] = 0;
   1.110 +	modkeys = glutGetModifiers();
   1.111  }
   1.112  
   1.113 -bool bnstate[16];
   1.114 -int prev_x, prev_y;
   1.115 -
   1.116  void mouse(int bn, int st, int x, int y)
   1.117  {
   1.118  	bnstate[bn - GLUT_LEFT_BUTTON] = st == GLUT_DOWN;
   1.119  	prev_x = x;
   1.120  	prev_y = y;
   1.121 +	modkeys = glutGetModifiers();
   1.122  
   1.123  	if(bn == GLUT_LEFT_BUTTON && st == GLUT_DOWN) {
   1.124  		cur_point = screen_to_world(x, y);
   1.125 @@ -236,6 +258,10 @@
   1.126  
   1.127  	if(bnstate[0]) {
   1.128  		cur_point = screen_to_world(x, y);
   1.129 +		if(keystate['s'] || keystate['S']) {
   1.130 +			cur_point.x = round(cur_point.x / snap_dist) * snap_dist;
   1.131 +			cur_point.y = round(cur_point.y / snap_dist) * snap_dist;
   1.132 +		}
   1.133  		glutPostRedisplay();
   1.134  	}
   1.135  	if(bnstate[1]) {
   1.136 @@ -268,7 +294,7 @@
   1.137  Vector2 project(const Vector2 &v)
   1.138  {
   1.139  	Vector4 ppt = Vector4(v.x, 0, -v.y, 1).transformed(proj);
   1.140 -	return Vector2(ppt.x / ppt.w, ppt.z / ppt.w);
   1.141 +	return Vector2(ppt.x / ppt.w, calc_proj_dist(proj_vfov));
   1.142  }
   1.143  
   1.144  Vector2 unproject(const Vector2 &v)
   1.145 @@ -279,3 +305,8 @@
   1.146  	Vector4 res4 = v4.transformed(inv_proj);
   1.147  	return Vector2(res4.x / res4.w, -res4.z / res4.w);
   1.148  }
   1.149 +
   1.150 +float calc_proj_dist(float fov)
   1.151 +{
   1.152 +	return 1.0 / tan(DEG_TO_RAD(fov) / 2.0);
   1.153 +}