Merge pull request #4475 from Goober5000/fix_erroneous_angle_modification

fix erroneous position/angle modification

Author: Goober5000

fred2/orienteditor.cpp

@@ -21,7 +21,8 @@
 static char THIS_FILE[] = __FILE__;
 #endif
 
-const float input_threshold = 0.01f;		// smallest increment of input box
+constexpr auto INPUT_THRESHOLD = 0.01f;		// smallest increment of input box
+constexpr auto INPUT_FORMAT = "%.01f";
 
 /////////////////////////////////////////////////////////////////////////////
 // orient_editor dialog
@@ -45,15 +46,15 @@ orient_editor::orient_editor(CWnd* pParent /*=NULL*/)
 
 	Assert(query_valid_object());
 	auto pos = &Objects[cur_object_index].pos;
-	m_position_x.Format("%.01f", pos->xyz.x);
-	m_position_y.Format("%.01f", pos->xyz.y);
-	m_position_z.Format("%.01f", pos->xyz.z);
+	m_position_x.Format(INPUT_FORMAT, pos->xyz.x);
+	m_position_y.Format(INPUT_FORMAT, pos->xyz.y);
+	m_position_z.Format(INPUT_FORMAT, pos->xyz.z);
 
 	angles ang;
 	vm_extract_angles_matrix(&ang, &Objects[cur_object_index].orient);
-	m_orientation_p.Format("%.01f", to_degrees(ang.p));
-	m_orientation_b.Format("%.01f", to_degrees(ang.b));
-	m_orientation_h.Format("%.01f", to_degrees(ang.h));
+	m_orientation_p.Format(INPUT_FORMAT, to_degrees(ang.p));
+	m_orientation_b.Format(INPUT_FORMAT, to_degrees(ang.b));
+	m_orientation_h.Format(INPUT_FORMAT, to_degrees(ang.h));
 }
 
 void orient_editor::DoDataExchange(CDataExchange* pDX)
@@ -182,29 +183,47 @@ BOOL orient_editor::OnInitDialog()
 	return TRUE;
 }
 
-bool orient_editor::close(float val, const CString &str)
+/**
+ * Checks whether the position value is close enough to the input string value that we can assume the input has not changed.
+ */
+bool orient_editor::is_close(float val, const CString &input_str) const
 {
-	float diff = val - convert(str);
-	return diff > -input_threshold && diff < input_threshold;
+	val = perform_input_rounding(val);
+	float input_val = convert(input_str);
+
+	float diff = val - input_val;
+	return abs(diff) < INPUT_THRESHOLD;
+}
+
+/**
+ * Checks whether the angle value is close enough to the input string value that we can assume the input has not changed.
+ */
+bool orient_editor::is_angle_close(float rad, const CString &input_str) const
+{
+	float deg = perform_input_rounding(to_degrees(rad));
+	float input_deg = normalize_degrees(convert(input_str));
+
+	float diff = deg - input_deg;
+	return abs(diff) < INPUT_THRESHOLD;
 }
 
 bool orient_editor::query_modified()
 {
-	if (!close(Objects[cur_object_index].pos.xyz.x, m_position_x))
+	if (!is_close(Objects[cur_object_index].pos.xyz.x, m_position_x))
 		return true;
-	if (!close(Objects[cur_object_index].pos.xyz.y, m_position_y))
+	if (!is_close(Objects[cur_object_index].pos.xyz.y, m_position_y))
 		return true;
-	if (!close(Objects[cur_object_index].pos.xyz.z, m_position_z))
+	if (!is_close(Objects[cur_object_index].pos.xyz.z, m_position_z))
 		return true;
 
 	angles ang;
 	vm_extract_angles_matrix(&ang, &Objects[cur_object_index].orient);
 
-	if (!close(to_degrees(ang.p), m_orientation_p))
+	if (!is_angle_close(ang.p, m_orientation_p))
 		return true;
-	if (!close(to_degrees(ang.b), m_orientation_b))
+	if (!is_angle_close(ang.b, m_orientation_b))
 		return true;
-	if (!close(to_degrees(ang.h), m_orientation_h))
+	if (!is_angle_close(ang.h, m_orientation_h))
 		return true;
 
 	if (((CButton *) GetDlgItem(IDC_POINT_TO_CHECKBOX))->GetCheck() == TRUE)
@@ -224,7 +243,7 @@ void orient_editor::OnOK()
 
 	// there's enough difference in our position that we're changing it
 	cur_pos = &Objects[cur_object_index].pos;
-	if (!close(cur_pos->xyz.x, m_position_x) || !close(cur_pos->xyz.y, m_position_y) || !close(cur_pos->xyz.z, m_position_z))
+	if (!is_close(cur_pos->xyz.x, m_position_x) || !is_close(cur_pos->xyz.y, m_position_y) || !is_close(cur_pos->xyz.z, m_position_z))
 	{
 		vec3d pos;
 		pos.xyz.x = convert(m_position_x);
@@ -237,7 +256,7 @@ void orient_editor::OnOK()
 
 	// there's enough difference in our orientation that we're changing it
 	vm_extract_angles_matrix(&ang, &Objects[cur_object_index].orient);
-	if (!close(to_degrees(ang.p), m_orientation_p) || !close(to_degrees(ang.b), m_orientation_b) || !close(to_degrees(ang.h), m_orientation_h))
+	if (!is_angle_close(ang.p, m_orientation_p) || !is_angle_close(ang.b, m_orientation_b) || !is_angle_close(ang.h, m_orientation_h))
 	{
 		ang.p = fl_radians(convert(m_orientation_p));
 		ang.b = fl_radians(convert(m_orientation_b));
@@ -354,6 +373,11 @@ void orient_editor::actually_point_object(object *ptr)
 float orient_editor::to_degrees(float rad)
 {
 	float deg = fl_degrees(rad);
+	return normalize_degrees(deg);
+}
+
+float orient_editor::normalize_degrees(float deg)
+{
 	while (deg < -180.0f)
 		deg += 180.0f;
 	while (deg > 180.0f)
@@ -364,7 +388,10 @@ float orient_editor::to_degrees(float rad)
 	return deg;
 }
 
-float orient_editor::convert(const CString &str)
+/**
+ * Extract a float from the CString, being mindful of any comma separators.
+ */
+float orient_editor::convert(const CString &str) const
 {
 	char buf[256];
 	size_t i, j, len;
@@ -379,6 +406,18 @@ float orient_editor::convert(const CString &str)
 	return (float) atof(buf);
 }
 
+/**
+ * Perform rounding of the float value by loading it into the input box format string and parsing it again.
+ * This accounts for not only decimal rounding to the precision of the input box, but also floating point rounding due to inexact fractions such as 1/10.
+ * See also GitHub PR #4475.
+ */
+float orient_editor::perform_input_rounding(float val) const
+{
+	CString str;
+	str.Format(INPUT_FORMAT, val);
+	return convert(str);
+}
+
 void orient_editor::OnPointTo()
 {
 	UpdateData(TRUE);

fred2/orienteditor.h

@@ -24,6 +24,7 @@ class orient_editor : public CDialog
 	orient_editor(CWnd* pParent = NULL);   // standard constructor
 
 	static float to_degrees(float radians);
+	static float normalize_degrees(float degrees);
 
 // Dialog Data
 	//{{AFX_DATA(orient_editor)
@@ -69,8 +70,12 @@ class orient_editor : public CDialog
 	DECLARE_MESSAGE_MAP()
 
 private:
-	float convert(const CString &str);
-	bool close(float val, const CString &str);
+	float convert(const CString &str) const;
+	float perform_input_rounding(float val) const;
+
+	bool is_close(float val, const CString &input_str) const;
+	bool is_angle_close(float rad, const CString &input_str) const;
+
 	int total;
 	int index[MAX_OBJECTS];
 	void actually_point_object(object *ptr);