Index: draw.html
==================================================================
--- draw.html
+++ draw.html
@@ -1,20 +1,22 @@
 <html>
 <script src='matrix_vector_lib.js' ></script>
 
 <script>
 
-
+//  TODO rotate selected points
 //  TODO control with zoom rotate or pan means that action is only applied to the camera not the selected points.
 
 
 //  TODO clicking and dragging on a line allows you to place a point somewhere on that line.  Perhaps with the modifier key it would break up the existing line into line segments.
 
 //  TODO when lines are deleted, readd the solo points to the solo_points list
 //  
 
 //  TODO z for undo shift + z for redo.
+//
+//  TODO 
 //
 
 //  TODO drop down minimalist menu in top right of canvas.
 
 
@@ -24,18 +26,88 @@
 var canvas;
 var origin = [0, 0, 0];
 var frame_rate = 20;
 var saveTimeout = 10*1000;
 
-var no_rotate_area = 0.80;
-            
-            
+var forward_axis_size = 0.1;
+var vertical_axis_size = 0.05;      
+
+
+
+
+// to prevent camera from rotating beyond straight vertical
+var vertical_camera_rotation = 0;
+var zoom_dist = 1;
+var zoom_factor = 0.83;
+var zoom_scale = 2.667;  // scalar zoom property.
+var last_zoom_dist = 1;
+
+
+// camera animation
+var max_move_delta = 0.01;
+var max_angle_delta = Math.PI;
+
+var delta_horizontal_angle = 0;
+var delta_vertical_angle = 0;
+var delta_position = [0,0,0];
+
+
+//  Use to rotate selected points about a vector line
+var selection_rotation_vector = null;
+var rotation_center = origin.slice(0);
+
+
+
+
+
+var points = []; //global
+var solo_points = {};
+var lines = [];
+
+var point_projections = [];
+var line_midpoint_projections = [];
+
+var highlight_object = null;
+var mouse_dragging = false;
+var last_mouse_down = null;
+var mouse_loc = null;
+var MIN_DRAG_DIST = 10;
+var POINT_HIGHLIGHT_DIST = 10;
+var LINE_HIGHLIGHT_DIST = 15;
+
+var selected_points = [];
+var selected_lines = [];
+
+var msg = //"3D drawing tool\n\n" +
+          "Select     Left Click\n" +
+		  "Rotate     Right Click\n" +
+		  "Move       wasd, qe\n" +
+		  "Copy       Space\n" +
+		  "Delete     x\n" +
+		  "\n" +
+		  "Click the red dot to create a point\n" +
+	      "Spam a motion key to increase speed\n";		  
+	
+	
+
+
+var view_transform =
+    [[1, 0, 0],
+     [0, 1, 0],
+     [0, 0, 1]];
+    
+
+
+
+
+
+
 
             
 
 var key_state = {};
-var key_state_augmentation_delay = 150; // the permissible time in milliseconds since the last key event to still allow the key state to augment instead of clearing.
+var key_state_augmentation_timeout = 150; // the permissible time in milliseconds since the last key event to still allow the key state to augment instead of clearing.
 
 function addKeyListener(keycode, func){
     if(!key_state[keycode]) key_state[keycode] = {};
     
     var key_obj = key_state[keycode];
@@ -62,11 +134,11 @@
     
     state = 0;
     
     var latest = key_obj.latest;
 
-    if(latest && time - latest < key_state_augmentation_delay)
+    if(latest && time - latest < key_state_augmentation_timeout)
         state = key_obj.state = key_obj.lastState + 1;
     else
         state = key_obj.state = 1;
         
     key_obj.latest = time;
@@ -148,13 +220,12 @@
     var velocityChange = [0, 0, 0];
     velocityChange[direction] = delta;
     vector_add(delta_position, velocityChange, delta_position); }
     
 
-//
-//  This 
-//
+	
+
     
 function leftPress(e, s, lasts){
     changeVelocity(0, false, s, lasts); }
     
 function rightPress(e, s, lasts){
@@ -320,60 +391,23 @@
 				 && miny < _y && _y < maxy){
 				   selected_points.push(i); }}}                
         }});
 
 
-
-
-
-// to prevent camera from rotating beyond straight vertical
-var vertical_camera_rotation = 0;
-var NAVIGATION_ZOOM_DIST = 0.01;
-var zoom_dist = 1;
-var zoom_factor = 0.83;
-var zoom_scale = 2.667;  // scalar zoom property.
-var last_zoom_dist = 1;
-
-
-// camera animation
-var max_move_delta = 0.01;
-var max_angle_delta = Math.PI / 2;
-
-var delta_horizontal_angle = 0;
-var delta_vertical_angle = 0;
-var delta_position = [0,0,0];
-
-
-
-
-
-var points = []; //global
-var solo_points = {};
-var lines = [];
-
-var point_projections = [];
-var line_midpoint_projections = [];
-
-var highlight_object = null;
-var mouse_dragging = false;
-var last_mouse_down = null;
-var mouse_loc = null;
-var MIN_DRAG_DIST = 10;
-var POINT_HIGHLIGHT_DIST = 10;
-var LINE_HIGHLIGHT_DIST = 15;
-
-var selected_points = [];
-var selected_lines = [];
-
-var msg = "3D drawing tool";
-
-
-var view_transform =
-    [[1, 0, 0],
-     [0, 1, 0],
-     [0, 0, 1]];
-    
+// right click
+addKeyListener(1002, function(e, s, lasts){
+	if(s == 0){
+		delta_horizontal_angle = 0;
+		delta_vertical_angle = 0; }});
+
+
+function writeMsg(canvas, msg){
+	var lines = msg.split("\n");
+	var ctx = canvas.getContext("2d");
+	ctx.font = "9pt sans-serif"
+	for(var i = 0; i < lines.length; ++i){
+		ctx.fillText(lines[i], 5, 10 + 15 *  i); }}
 
     
 //  camera functions
 
 function rotateView(norm, theta, cameracentric){
@@ -543,31 +577,47 @@
         
         ctx.moveTo(x0, y0);
         ctx.lineTo(x1, y1); }
     
     ctx.clearRect(0, 0, w, h);
-    var hoffset = h * (1 - no_rotate_area)/ 2;
-    var woffset = w * (1 - no_rotate_area)/ 2;
-    
-    ctx.fillStyle = "rgba(128, 128, 128, 0.05)";
-    ctx.fillRect(0, 0, w, hoffset);
-    ctx.fillRect(0, hoffset, woffset, h - 2 * hoffset);
-    ctx.fillRect(w - woffset, hoffset, woffset, h - 2 * hoffset);
-    ctx.fillRect(0, h - hoffset, w, hoffset);
-    
-    ctx.fillStyle = "rgb(0, 0, 128)";
+	
+    
+	ctx.strokeStyle = "rgba(0, 0, 0, 0.9)";
     ctx.stroke();
     
+	ctx.fillStyle = "rgba(0, 0, 0, 0.9)";
     for(var k in solo_points){
        var pt = point_projections[k];
        if(pt) ctx.fillRect(pt[0] - 2, pt[1] - 2, 4, 4); }
         
     
-    
-    
+
+	// axis lines and dots
+	ctx.beginPath();
+    var faxis_pt = project(canvas, vector_add(origin, [0, 0, forward_axis_size, 0, 0]), view_transform, origin);
+	var vaxis_pt = project(canvas, vector_add(origin, [0, -vertical_axis_size, 0]), view_transform, origin);
+	
+	ctx.fillStyle = "rgba(0,0,0,0.9)";
+	
+	if(faxis_pt){
+		ctx.moveTo(w/2, h/2);
+		ctx.lineTo(faxis_pt[0], faxis_pt[1]);
+		ctx.fillRect(faxis_pt[0] - 2, faxis_pt[1] - 2, 4, 4); }
+		
+	if(vaxis_pt){
+		ctx.moveTo(w/2, h/2);
+		ctx.lineTo(vaxis_pt[0], vaxis_pt[1]);
+		ctx.fillRect(vaxis_pt[0] - 2, vaxis_pt[1] - 2, 4, 4); }
+		
+	ctx.stroke();	
+	
+	
+
+    // red center dot.
 	ctx.fillStyle = "rgba(250, 0, 0, 0.9)";
 	ctx.fillRect(w/2 - 2, h/2 - 2, 4, 4);
+		
 	
 	for(var i = 0; i < selected_points.length; ++i){
 		var pt;
 		
 		if(selected_points[i] == -1)
@@ -616,31 +666,33 @@
 		document.body.style.cursor = "crosshair"; }
 	
 	if(mouse_dragging){
 	
 		if(selected_points.length && (!key_state[16] || !key_state[16].state)){  // if shift is held, we are selecting more points.
-			if(mouse_loc){
+			if(mouse_loc && key_state[1000] && key_state[1000].state){
 				ctx.beginPath();
-				for(var i = 0; i < selected_points.length; ++i){
-					var pt = point_projections[selected_points[i]];
-					if(pt){
-						ctx.moveTo(mouse_loc[0], mouse_loc[1]);
-						ctx.lineTo(pt[0], pt[1]); }}
+				var pt = point_projections[selected_points[0]];
+				if(pt){
+					ctx.moveTo(mouse_loc[0], mouse_loc[1]);
+					ctx.lineTo(pt[0], pt[1]); }
 				ctx.stroke(); }}
-		
-		else if(mouse_loc && last_mouse_down){  // select points inside square            
-			var minx = Math.min(mouse_loc[0], last_mouse_down[0]);
-			var maxx = Math.max(mouse_loc[0], last_mouse_down[0]);
-			var miny = Math.min(mouse_loc[1], last_mouse_down[1]);
-			var maxy = Math.max(mouse_loc[1], last_mouse_down[1]);
-			ctx.beginPath();
-			ctx.rect(minx, miny, maxx-minx, maxy-miny);
-			ctx.stroke(); }
+				
+		else if(mouse_loc && last_mouse_down){  
+		
+		
+		    if(key_state[1000] && key_state[1000].state){     // select points inside square
+				var minx = Math.min(mouse_loc[0], last_mouse_down[0]);
+				var maxx = Math.max(mouse_loc[0], last_mouse_down[0]);
+				var miny = Math.min(mouse_loc[1], last_mouse_down[1]);
+				var maxy = Math.max(mouse_loc[1], last_mouse_down[1]);
+				ctx.beginPath();
+				ctx.rect(minx, miny, maxx - minx, maxy - miny);
+				ctx.stroke(); }}
 	}
     
     ctx.fillStyle = "rgb(0,0,0)";
-    ctx.fillText(msg, 5, 20); }
+	writeMsg(canvas, msg); }
 
     
     
 window.onload = function(){
 
@@ -662,13 +714,12 @@
 
     
     
     function getRotationAngle(x, size, max, center_size){
 
-        if(!center_size) center_size = 0.25;  // the proportional size of the area in which no rotation is effected by the mouse movement
+        if(!center_size) center_size = 0.05;  // the proportional size of the area in which no rotation is effected by the mouse movement
         if(!max) max = Math.PI/128;
-        x -= size/2;
         
         //  center does nothing
         if(Math.abs(x) < size * center_size/2) x = 0;
         else if(x < 0) x += size * center_size/2;
         else           x -= size * center_size/2;
@@ -697,13 +748,15 @@
             if(dist2 > MIN_DRAG_DIST * MIN_DRAG_DIST){
                 mouse_dragging = true; }}
                 
 
 				
-		delta_horizontal_angle = getRotationAngle(x, w, max_angle_delta/frame_rate, no_rotate_area);
-		delta_vertical_angle = -getRotationAngle(y, h, max_angle_delta/frame_rate, no_rotate_area);
-		
+	    if(key_state[1002] && key_state[1002].state && last_mouse_down){
+			delta_horizontal_angle = getRotationAngle(x - last_mouse_down[0], w, max_angle_delta/frame_rate, 0);
+			delta_vertical_angle = -getRotationAngle(y - last_mouse_down[1], h, max_angle_delta/frame_rate, 0); }
+			
+			
 		var min_point_dist2 = LINE_HIGHLIGHT_DIST * LINE_HIGHLIGHT_DIST;
 		highlight_object = null;
 		
 		var _x = canvas.width/2 - x;
 		var _y = canvas.height/2 - y;

Index: matrix_vector_lib.js
==================================================================
--- matrix_vector_lib.js
+++ matrix_vector_lib.js
@@ -4,10 +4,12 @@
 //
 //
 
 function vector_add(a, b, result){
     if(!result) result = [];
+	if(!a) throw "first argument to vector_add missing";
+	if(!b) throw "second argument to vector_add missing";
 
     if(a.length > b.lemgth){
         var tmp = a;
         a = b; b = tmp; }
 
@@ -19,18 +21,21 @@
 
     return result; }
 
     
 function vector_cpy(result, a){
+	if(!a) throw "first argument to vector_cpy missing";
     for(var i = 0; i < a.length; ++i){
         result[i] = a[i]; }
 }
 
 
 
 function vector_minus(a, b, result){
     if(!result) result = [];
+	if(!a) throw "first argument to vector_minus missing";
+	if(!b) throw "second argument to vector_minus missing";
 
     var lim = Math.max(a.length, b.length);
     
     for(var i = 0; i < lim; ++i){
 		var aValue, bValue;
@@ -51,25 +56,31 @@
    
 
 
 function vector_dot(a, b){
     var lim = Math.min(a.length, b.length);
+	if(!a) throw "first argument to vector_dot missing";
+	if(!b) throw "second argument to vector_dot missing";
+	
     var result = 0;
 
     for(var i = 0; i < lim; ++i){
         result += a[i] * b[i]; }
 
     return result; }
     
     
 function vector_norm(a){
+	if(!a) throw "argument to vector_norm missing";
     return Math.sqrt(vector_dot(a,a)); }
 
     
     
     
 function vector_scale(a, s, result){
+	if(!a) throw "first argument to vector_scale missing";
+	if(s === undefined || s === null) throw "scalar argument to vector_scale missing";
 
     if(!result) result = [];
     
     for(var i = 0; i < a.length; ++i){
         result[i] = s * a[i]; }
@@ -78,10 +89,12 @@
 
 
 
 // returns true iff the zero tail padded vectors match
 function vector_cmp(a, b){
+	if(!a) throw "first argument to vector_cmp missing";
+	if(!b) throw "second argument to vector_cmp missing";
 
     if(a.length > b.length){
          var tmp = a;
          a = b; b = tmp; }
 
@@ -95,11 +108,13 @@
             
     return true; }
     
     
     
-function midpoint(a, b, result){
+function vector_midpoint(a, b, result){
+	if(!a) throw "first argument to vector_midpoint missing";
+	if(!b) throw "second argument to vector_midpoint missing";
 
     if(b.length > a.length){
         var tmp = a;
         a = b; b = tmp; }
         
@@ -117,10 +132,11 @@
 
 
 
 //this function may not care, but the expected matrix format in this project is a list of column vectors.
 function matrix_transpose(matrix){
+	if(!matrix) throw "argument to matrix_transpose missing";
 
     var result = [];
     var dim0 = matrix.length;
     if(!dim0) 
 		return result;
@@ -141,10 +157,12 @@
 
     
     
 
 function matrix_mult(a, b){
+	if(!a) throw "first argument to matrix_mult missing";
+	if(!b) throw "second argument to matrix_mult missing";
 
     var result = [];
     var a = matrix_transpose(a);
     var dim0 = a.length;
     var dim1 = b.length;
@@ -162,10 +180,11 @@
     
 // finds the inverse of a 3 by 3 matrix, returns false if matrix has determinant zero.
 //
 
 function matrix33inv(m){
+    if(!m) throw "argument to matrix33inv missing";
 
     // the matrix format is a list of column vectors.
     var a = m[0][0];
 	var b = m[1][0];
 	var c = m[2][0];
@@ -205,12 +224,16 @@
 		          [di*D, di*E, di*F],
 		          [di*G, di*H, di*K]];
 
 	return result;  }
 
-    
+	
+// does not check if function is differentiable.
+
 function compute_gradient(func, point, error){
+	if(!func) throw "function argument to compute_gradient missing";
+	if(!point) throw "point argument to compute_gradient missing";
 
     if(!error) error = 0.00001;
 
     // find gradient
     var otherpoint = point.slice(0);
@@ -234,11 +257,13 @@
 // equation at:
 // http://inside.mines.edu/~gmurray/ArbitraryAxisRotation/ArbitraryAxisRotation.html
 // creates a rotation matrix about the given vector.
 //
 function vector_rotation(vector, s){
-
+	if(!vector) throw "vector argument to vector_rotation missing";
+	if(!s) throw "angle argument to vector_rotation missing";
+	
     var len = Math.sqrt(vector[0]*vector[0]
                         + vector[1]*vector[1]
                         + vector[2]*vector[2]);
 
     var u = vector[0]/len;

