Correct assert failure in debug mode with lasso select

Just do early output and don't bother with any GLSL program bind when
there is not enough points of lasso to draw.

This could have happened at the very beginning of the stroke.

1 files changed, 11 insertions, 6 deletions

diff --git a/source/blender/windowmanager/intern/wm_gesture.c b/source/blender/windowmanager/intern/wm_gesture.c
index 74dd9914c30..da490f793bb 100644
--- a/source/blender/windowmanager/intern/wm_gesture.c
+++ b/source/blender/windowmanager/intern/wm_gesture.c
@@ -400,6 +400,16 @@ static void wm_gesture_draw_lasso(wmWindow *win, wmGesture *gt, bool filled)
 		draw_filled_lasso(win, gt);
 	}
 
+	numverts = gt->points;
+	if (gt->type == WM_GESTURE_LASSO) {
+		numverts++;
+	}
+
+	/* Nothing to drawe, do early output. */
+	if(numverts < 2) {
+		return;
+	}
+
 	VertexFormat* format = immVertexFormat();
 	unsigned pos = add_attrib(format, "pos", COMP_F32, 2, KEEP_FLOAT);
 	unsigned line_origin = add_attrib(format, "line_origin", COMP_F32, 2, KEEP_FLOAT);
@@ -415,11 +425,6 @@ static void wm_gesture_draw_lasso(wmWindow *win, wmGesture *gt, bool filled)
 	immUniform1f("dash_width", 2.0f);
 	immUniform1f("dash_width_on", 1.0f);
 
-	numverts = gt->points;
-	if (gt->type == WM_GESTURE_LASSO) {
-		numverts++;
-	}
-
 	immBegin(PRIM_LINE_STRIP, numverts);
 
 	for (i = 0; i < gt->points; i++, lasso += 2) {
@@ -441,7 +446,7 @@ static void wm_gesture_draw_lasso(wmWindow *win, wmGesture *gt, bool filled)
 	}
 
 	immEnd();
-	
+
 	immUnbindProgram();
 }