From 3dbfebc42caada8bb969a936cfb7a9f8ad730ca6 Mon Sep 17 00:00:00 2001
From: Antony Riakiotakis <kalast@gmail.com>
Date: Fri, 30 Jan 2015 19:47:58 +0100
Subject: First version of constrained line strokes - there's some flickering
 still, will look into it later.

---
 source/blender/editors/sculpt_paint/paint_stroke.c | 64 ++++++++++++++++++----
 1 file changed, 54 insertions(+), 10 deletions(-)

(limited to 'source/blender/editors/sculpt_paint/paint_stroke.c')

diff --git a/source/blender/editors/sculpt_paint/paint_stroke.c b/source/blender/editors/sculpt_paint/paint_stroke.c
index bb875d2ef00..79bf8c893df 100644
--- a/source/blender/editors/sculpt_paint/paint_stroke.c
+++ b/source/blender/editors/sculpt_paint/paint_stroke.c
@@ -122,6 +122,8 @@ typedef struct PaintStroke {
 
 	float zoom_2d;
 	int pen_flip;
+	
+	bool constrain_line;
 
 	StrokeGetLocation get_location;
 	StrokeTestStart test_start;
@@ -654,10 +656,11 @@ PaintStroke *paint_stroke_new(bContext *C,
 	get_imapaint_zoom(C, &zoomx, &zoomy);
 	stroke->zoom_2d = max_ff(zoomx, zoomy);
 
-	if ((br->flag & BRUSH_CURVE) &&
-	    RNA_struct_property_is_set(op->ptr, "mode"))
+	if (stroke->stroke_mode == BRUSH_STROKE_INVERT)
 	{
-		RNA_enum_set(op->ptr, "mode", BRUSH_STROKE_NORMAL);
+		if (br->flag & (BRUSH_CURVE | BRUSH_LINE)) {
+			RNA_enum_set(op->ptr, "mode", BRUSH_STROKE_NORMAL);
+		}
 	}
 	/* initialize here */
 	ups->overlap_factor = 1.0;
@@ -996,6 +999,36 @@ static bool paint_stroke_curve_end(bContext *C, wmOperator *op, PaintStroke *str
 	return false;
 }
 
+static void paint_stroke_line_constrain (bContext *C, PaintStroke *stroke, float mouse[2]) {
+	if (stroke->constrain_line) {
+		wmWindow *win = CTX_wm_window(C);
+		ARegion *ar = CTX_wm_region(C);
+		float line[2];
+		float angle, len, res;
+		
+		sub_v2_v2v2(line, mouse, stroke->last_mouse_position);
+		angle = atan2(line[1], line[0]);
+		len = len_v2(line);
+		
+		/* divide angle by PI/8 */
+		angle = 4.0 * angle / M_PI;
+		
+		/* now take residue, if less than */
+		res = angle - floor(angle);
+		
+		if (res <= 0.5) {
+			angle = floor(angle) * M_PI / 4.0;
+		}
+		else {
+			angle = (floor(angle) + 1.0) * M_PI / 4.0;
+		}
+		
+		line[0] = len * cos(angle) + stroke->last_mouse_position[0] + ar->winrct.xmin;
+		line[1] = len * sin(angle) + stroke->last_mouse_position[1] + ar->winrct.ymin;
+		
+		WM_cursor_warp(win, line[0], line[1]);
+	}
+}
 
 int paint_stroke_modal(bContext *C, wmOperator *op, const wmEvent *event)
 {
@@ -1069,7 +1102,9 @@ int paint_stroke_modal(bContext *C, wmOperator *op, const wmEvent *event)
 
 	if (event->type == stroke->event_type && !first_modal) {
 		if (event->val == KM_RELEASE) {
-			paint_stroke_line_end (C, op, stroke, sample_average.mouse);
+			copy_v2_fl2(mouse, event->mval[0], event->mval[1]);
+			paint_stroke_line_constrain(C, stroke, mouse);
+			paint_stroke_line_end (C, op, stroke, mouse);
 			stroke_done(C, op);
 			return OPERATOR_FINISHED;
 		}
@@ -1079,13 +1114,22 @@ int paint_stroke_modal(bContext *C, wmOperator *op, const wmEvent *event)
 		stroke_done(C, op);
 		return OPERATOR_FINISHED;
 	}
-	else if ((br->flag & BRUSH_LINE) && stroke->stroke_started &&
-	         (first_modal || (ELEM(event->type, MOUSEMOVE, INBETWEEN_MOUSEMOVE))))
-	{
-		if ((br->mtex.brush_angle_mode & MTEX_ANGLE_RAKE) || (br->mtex.brush_angle_mode & MTEX_ANGLE_RAKE)) {
-			copy_v2_v2(stroke->ups->last_rake, stroke->last_mouse_position);
+	else if (br->flag & BRUSH_LINE) {
+		if (event->ctrl)
+			stroke->constrain_line = true;
+		else 
+			stroke->constrain_line = false;
+
+		copy_v2_fl2(mouse, event->mval[0], event->mval[1]);
+		paint_stroke_line_constrain(C, stroke, mouse);
+		
+		if (stroke->stroke_started && (first_modal || (ELEM(event->type, MOUSEMOVE, INBETWEEN_MOUSEMOVE))))
+		{
+			if ((br->mtex.brush_angle_mode & MTEX_ANGLE_RAKE) || (br->mtex.brush_angle_mode & MTEX_ANGLE_RAKE)) {
+				copy_v2_v2(stroke->ups->last_rake, stroke->last_mouse_position);
+			}
+			paint_calculate_rake_rotation(stroke->ups, br, mouse);
 		}
-		paint_calculate_rake_rotation(stroke->ups, br, sample_average.mouse);
 	}
 	else if (first_modal ||
 	         /* regular dabs */
-- 
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