# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1422143968 -7200
# Node ID e6ed6acee42f8f39c4ac90645562c604af3f544d
# Parent  64483c640a3849c429248ecf845476007955faf3
more foo

diff -r 64483c640a38 -r e6ed6acee42f main.cc
--- a/main.cc	Sat Jan 24 17:49:35 2015 +0200
+++ b/main.cc	Sun Jan 25 01:59:28 2015 +0200
@@ -19,20 +19,27 @@
 Vector2 screen_to_world(int x, int y);
 Vector2 project(const Vector2 &v);
 Vector2 unproject(const Vector2 &v);
+float calc_proj_dist(float fov);
 
 int win_xsz, win_ysz;
 float aspect;
 
 Matrix4x4 proj;
+float proj_offset;
 Vector2 cur_point;
 bool cur_point_valid;
 
 float proj_near = 0.5, proj_far = 50.0;
-float proj_vfov = 50.0;
+float proj_vfov = 60.0;
 
 bool keystate[256];
+bool bnstate[16];
+int prev_x, prev_y;
+unsigned int modkeys;
+
 dtx_font *font;
-float pan[2] = {0, 0.85}, zoom = 0.4;
+float pan[2] = {0, 0.85}, zoom = 0.3;
+float snap_dist = 0.25;
 
 int main(int argc, char **argv)
 {
@@ -65,6 +72,7 @@
 
 	glEnable(GL_MULTISAMPLE);
 	proj.set_perspective(DEG_TO_RAD(proj_vfov), 1, 1.0, 50.0);
+	proj.translate(Vector3(proj_offset, 0, 0));
 	return true;
 }
 
@@ -103,9 +111,9 @@
 		glEnd();
 		glDisable(GL_LINE_STIPPLE);
 
-		glColor3f(0.15, 0.5, 0.15);
+		glColor3f(0.2, 0.5, 0.2);
 		draw_label(cur_point, "(%.2f, %.2f)", cur_point.x, cur_point.y);
-		glColor3f(0.4, 0.1, 0.1);
+		glColor3f(0.5, 0.2, 0.2);
 		draw_label(ppt, "(%.2f, %.2f)", ppt.x, ppt.y);
 	}
 
@@ -146,22 +154,36 @@
 
 void draw_frustum()
 {
-	Vector2 v0, v1;
+	Vector2 left[2], right[2];
 
 	glBegin(GL_LINES);
 	glColor3f(0.2, 0.4, 0.8);
 
-	v0 = unproject(Vector2(1, 0));
-	v1 = unproject(Vector2(1, 1));
-	LINE(v0.x, v0.y, v1.x, v1.y);
+	right[0] = unproject(Vector2(1, 0));
+	right[1] = unproject(Vector2(1, 1));
+	LINE(right[0].x, right[0].y, right[1].x, right[1].y);
 
-	v0 = unproject(Vector2(-1, 0));
-	v1 = unproject(Vector2(-1, 1));
-	LINE(v0.x, v0.y, v1.x, v1.y);
+	left[0] = unproject(Vector2(-1, 0));
+	left[1] = unproject(Vector2(-1, 1));
+	LINE(left[0].x, left[0].y, left[1].x, left[1].y);
 
-	LINE(-0.5, proj_near, 0.5, proj_near);
+	float dist = calc_proj_dist(proj_vfov);
+	LINE(-1, dist, 1, dist);
+	glEnd();
 
+	/* find the points where the frustum lines hit zero */
+	glEnable(GL_LINE_STIPPLE);
+	glLineStipple(3, 0x0101);
+
+	glBegin(GL_LINES);
+	for(int i=0; i<2; i++) {
+		Vector2 *v = i ? left : right;
+		float t = -v[1].y / (v[0].y - v[1].y);
+		float x = v[1].x + (v[0].x - v[1].x) * t;
+		LINE(v[0].x, v[0].y, x, 0);
+	}
 	glEnd();
+	glDisable(GL_LINE_STIPPLE);
 }
 
 void draw_label(const Vector2 &pos, const char *fmt, ...)
@@ -199,6 +221,7 @@
 void keyb(unsigned char key, int x, int y)
 {
 	keystate[key] = 1;
+	modkeys = glutGetModifiers();
 
 	switch(key) {
 	case 27:
@@ -209,16 +232,15 @@
 void keyb_up(unsigned char key, int x, int y)
 {
 	keystate[key] = 0;
+	modkeys = glutGetModifiers();
 }
 
-bool bnstate[16];
-int prev_x, prev_y;
-
 void mouse(int bn, int st, int x, int y)
 {
 	bnstate[bn - GLUT_LEFT_BUTTON] = st == GLUT_DOWN;
 	prev_x = x;
 	prev_y = y;
+	modkeys = glutGetModifiers();
 
 	if(bn == GLUT_LEFT_BUTTON && st == GLUT_DOWN) {
 		cur_point = screen_to_world(x, y);
@@ -236,6 +258,10 @@
 
 	if(bnstate[0]) {
 		cur_point = screen_to_world(x, y);
+		if(keystate['s'] || keystate['S']) {
+			cur_point.x = round(cur_point.x / snap_dist) * snap_dist;
+			cur_point.y = round(cur_point.y / snap_dist) * snap_dist;
+		}
 		glutPostRedisplay();
 	}
 	if(bnstate[1]) {
@@ -268,7 +294,7 @@
 Vector2 project(const Vector2 &v)
 {
 	Vector4 ppt = Vector4(v.x, 0, -v.y, 1).transformed(proj);
-	return Vector2(ppt.x / ppt.w, ppt.z / ppt.w);
+	return Vector2(ppt.x / ppt.w, calc_proj_dist(proj_vfov));
 }
 
 Vector2 unproject(const Vector2 &v)
@@ -279,3 +305,8 @@
 	Vector4 res4 = v4.transformed(inv_proj);
 	return Vector2(res4.x / res4.w, -res4.z / res4.w);
 }
+
+float calc_proj_dist(float fov)
+{
+	return 1.0 / tan(DEG_TO_RAD(fov) / 2.0);
+}