Assets: Snapping with visual feedback while dragging

The drag and drop feature of objects in 3D View has been modified to include:
- Snap the object being dragged.
- Visual feedback through a box and the placement tool grid.

Maniphest Tasks: T90198

Differential Revision: https://developer.blender.org/D12912

2 files changed, 31 insertions, 0 deletions

diff --git a/source/blender/gpu/GPU_immediate_util.h b/source/blender/gpu/GPU_immediate_util.h
index 3ea809d59a7..793348ad8d2 100644
--- a/source/blender/gpu/GPU_immediate_util.h
+++ b/source/blender/gpu/GPU_immediate_util.h
@@ -80,6 +80,10 @@ void imm_draw_box_checker_2d(float x1, float y1, float x2, float y2);
 
 void imm_draw_cube_fill_3d(uint pos, const float co[3], const float aspect[3]);
 void imm_draw_cube_wire_3d(uint pos, const float co[3], const float aspect[3]);
+void imm_draw_cube_corners_3d(uint pos,
+                              const float co[3],
+                              const float aspect[3],
+                              const float factor);
 
 void imm_draw_cylinder_fill_normal_3d(
     uint pos, uint nor, float base, float top, float height, int slices, int stacks);
diff --git a/source/blender/gpu/intern/gpu_immediate_util.c b/source/blender/gpu/intern/gpu_immediate_util.c
index d18dc862ce7..d848ea09a2a 100644
--- a/source/blender/gpu/intern/gpu_immediate_util.c
+++ b/source/blender/gpu/intern/gpu_immediate_util.c
@@ -428,6 +428,33 @@ void imm_draw_cube_wire_3d(uint pos, const float co[3], const float aspect[3])
   immEnd();
 }
 
+void imm_draw_cube_corners_3d(uint pos,
+                              const float co[3],
+                              const float aspect[3],
+                              const float factor)
+{
+  float coords[ARRAY_SIZE(cube_coords)][3];
+
+  for (int i = 0; i < ARRAY_SIZE(cube_coords); i++) {
+    madd_v3_v3v3v3(coords[i], co, cube_coords[i], aspect);
+  }
+
+  immBegin(GPU_PRIM_LINES, ARRAY_SIZE(cube_line_index) * 4);
+  for (int i = 0; i < ARRAY_SIZE(cube_line_index); i++) {
+    float vec[3], co[3];
+    sub_v3_v3v3(vec, coords[cube_line_index[i][1]], coords[cube_line_index[i][0]]);
+    mul_v3_fl(vec, factor);
+
+    immVertex3fv(pos, coords[cube_line_index[i][0]]);
+    add_v3_v3v3(co, coords[cube_line_index[i][0]], vec);
+    immVertex3fv(pos, co);
+    sub_v3_v3v3(co, coords[cube_line_index[i][1]], vec);
+    immVertex3fv(pos, co);
+    immVertex3fv(pos, coords[cube_line_index[i][1]]);
+  }
+  immEnd();
+}
+
 /**
  * Draw a cylinder. Replacement for gluCylinder.
  * _warning_ : Slow, better use it only if you no other choices.