1 files changed, 51 insertions, 0 deletions

diff --git a/source/blender/windowmanager/intern/wm_gesture.c b/source/blender/windowmanager/intern/wm_gesture.c
index b245bbe054d..6d36000abb4 100644
--- a/source/blender/windowmanager/intern/wm_gesture.c
+++ b/source/blender/windowmanager/intern/wm_gesture.c
@@ -199,10 +199,61 @@ int wm_gesture_evaluate(wmGesture *gesture, const wmEvent *event)
 
 /* ******************* gesture draw ******************* */
 
+static void wm_gesture_draw_line_active_side(rcti *rect)
+{
+  GPUVertFormat *format = immVertexFormat();
+  uint shdr_pos = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
+  uint shdr_col = GPU_vertformat_attr_add(format, "color", GPU_COMP_F32, 4, GPU_FETCH_FLOAT);
+
+  GPU_blend(GPU_BLEND_ALPHA);
+  immBindBuiltinProgram(GPU_SHADER_2D_SMOOTH_COLOR);
+
+  const float gradient_length = 150.0f * U.pixelsize;
+  float line_dir[2];
+  float gradient_dir[2];
+  float gradient_point[2][2];
+
+  const float line_start[2] = {rect->xmin, rect->ymin};
+  const float line_end[2] = {rect->xmax, rect->ymax};
+  const float color_line_gradient_start[4] = {0.2f, 0.2f, 0.2f, 0.4f};
+  const float color_line_gradient_end[4] = {0.0f, 0.0f, 0.0f, 0.0f};
+
+  sub_v2_v2v2(line_dir, line_end, line_start);
+  normalize_v2(line_dir);
+  ortho_v2_v2(gradient_dir, line_dir);
+  mul_v2_fl(gradient_dir, -1.0f);
+  mul_v2_fl(gradient_dir, gradient_length);
+  add_v2_v2v2(gradient_point[0], line_start, gradient_dir);
+  add_v2_v2v2(gradient_point[1], line_end, gradient_dir);
+
+  immBegin(GPU_PRIM_TRIS, 6);
+  immAttr4f(shdr_col, UNPACK4(color_line_gradient_start));
+  immVertex2f(shdr_pos, line_start[0], line_start[1]);
+  immAttr4f(shdr_col, UNPACK4(color_line_gradient_start));
+  immVertex2f(shdr_pos, line_end[0], line_end[1]);
+  immAttr4f(shdr_col, UNPACK4(color_line_gradient_end));
+  immVertex2f(shdr_pos, gradient_point[1][0], gradient_point[1][1]);
+
+  immAttr4f(shdr_col, UNPACK4(color_line_gradient_start));
+  immVertex2f(shdr_pos, line_start[0], line_start[1]);
+  immAttr4f(shdr_col, UNPACK4(color_line_gradient_end));
+  immVertex2f(shdr_pos, gradient_point[1][0], gradient_point[1][1]);
+  immAttr4f(shdr_col, UNPACK4(color_line_gradient_end));
+  immVertex2f(shdr_pos, gradient_point[0][0], gradient_point[0][1]);
+  immEnd();
+
+  immUnbindProgram();
+  GPU_blend(GPU_BLEND_NONE);
+}
+
 static void wm_gesture_draw_line(wmGesture *gt)
 {
   rcti *rect = (rcti *)gt->customdata;
 
+  if (gt->draw_active_side) {
+    wm_gesture_draw_line_active_side(rect);
+  }
+
   uint shdr_pos = GPU_vertformat_attr_add(
       immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);