Fix T70399: Grease Pencil Canvas Grid Overlay Broken after DRW refactor

Now the grid matrix is calculated when the shading group is created.

Also, the grid pass is only created when needed and reduce memory usage when the scene is not using grease pencil objects.

Reviewed By: fclem

Differential Revision: https://developer.blender.org/D5966

1 files changed, 34 insertions, 33 deletions

diff --git a/source/blender/draw/engines/gpencil/gpencil_engine.c b/source/blender/draw/engines/gpencil/gpencil_engine.c
index 10e9a79d143..aaadf680955 100644
--- a/source/blender/draw/engines/gpencil/gpencil_engine.c
+++ b/source/blender/draw/engines/gpencil/gpencil_engine.c
@@ -315,6 +315,7 @@ void GPENCIL_cache_init(void *vedata)
   ToolSettings *ts = scene->toolsettings;
   View3D *v3d = draw_ctx->v3d;
   Brush *brush = BKE_paint_brush(&ts->gp_paint->paint);
+  const View3DCursor *cursor = &scene->cursor;
 
   /* Special handling for when active object is GP object (e.g. for draw mode) */
   Object *obact = draw_ctx->obact;
@@ -540,11 +541,42 @@ void GPENCIL_cache_init(void *vedata)
     }
 
     /* grid pass */
-    if (v3d) {
+    if ((v3d) && (obact) && (obact->type == OB_GPENCIL)) {
       psl->grid_pass = DRW_pass_create("GPencil Grid Pass",
                                        DRW_STATE_WRITE_COLOR | DRW_STATE_BLEND_ALPHA |
                                            DRW_STATE_WRITE_DEPTH | DRW_STATE_DEPTH_ALWAYS);
       stl->g_data->shgrps_grid = DRW_shgroup_create(e_data.gpencil_line_sh, psl->grid_pass);
+
+      /* define grid orientation */
+      switch (ts->gp_sculpt.lock_axis) {
+        case GP_LOCKAXIS_VIEW: {
+          /* align always to view */
+          invert_m4_m4(stl->storage->grid_matrix, draw_ctx->rv3d->viewmat);
+          /* copy ob location */
+          copy_v3_v3(stl->storage->grid_matrix[3], obact->obmat[3]);
+          break;
+        }
+        case GP_LOCKAXIS_CURSOR: {
+          float scale[3] = {1.0f, 1.0f, 1.0f};
+          loc_eul_size_to_mat4(
+              stl->storage->grid_matrix, cursor->location, cursor->rotation_euler, scale);
+          break;
+        }
+        default: {
+          copy_m4_m4(stl->storage->grid_matrix, obact->obmat);
+          break;
+        }
+      }
+
+      /* Move the origin to Object or Cursor */
+      if (ts->gpencil_v3d_align & GP_PROJECT_CURSOR) {
+        copy_v3_v3(stl->storage->grid_matrix[3], cursor->location);
+      }
+      else {
+        copy_v3_v3(stl->storage->grid_matrix[3], obact->obmat[3]);
+      }
+      DRW_shgroup_uniform_mat4(
+          stl->g_data->shgrps_grid, "gpModelMatrix", stl->storage->grid_matrix);
     }
 
     /* blend layers pass */
@@ -615,8 +647,6 @@ void GPENCIL_cache_populate(void *vedata, Object *ob)
   Scene *scene = draw_ctx->scene;
   ToolSettings *ts = scene->toolsettings;
   View3D *v3d = draw_ctx->v3d;
-  const View3DCursor *cursor = &scene->cursor;
-  float grid_matrix[4][4];
 
   if (ob->type == OB_GPENCIL && ob->data) {
     bGPdata *gpd = (bGPdata *)ob->data;
@@ -677,36 +707,7 @@ void GPENCIL_cache_populate(void *vedata, Object *ob)
         ((ts->gpencil_v3d_align & GP_PROJECT_DEPTH_STROKE) == 0)) {
 
       stl->g_data->batch_grid = gpencil_get_grid(ob);
-
-      /* define grid orientation */
-      switch (ts->gp_sculpt.lock_axis) {
-        case GP_LOCKAXIS_VIEW: {
-          /* align always to view */
-          invert_m4_m4(grid_matrix, draw_ctx->rv3d->viewmat);
-          /* copy ob location */
-          copy_v3_v3(grid_matrix[3], ob->obmat[3]);
-          break;
-        }
-        case GP_LOCKAXIS_CURSOR: {
-          float scale[3] = {1.0f, 1.0f, 1.0f};
-          loc_eul_size_to_mat4(grid_matrix, cursor->location, cursor->rotation_euler, scale);
-          break;
-        }
-        default: {
-          copy_m4_m4(grid_matrix, ob->obmat);
-          break;
-        }
-      }
-
-      /* Move the origin to Object or Cursor */
-      if (ts->gpencil_v3d_align & GP_PROJECT_CURSOR) {
-        copy_v3_v3(grid_matrix[3], cursor->location);
-      }
-      else {
-        copy_v3_v3(grid_matrix[3], ob->obmat[3]);
-      }
-
-      DRW_shgroup_call_obmat(stl->g_data->shgrps_grid, stl->g_data->batch_grid, grid_matrix);
+      DRW_shgroup_call(stl->g_data->shgrps_grid, stl->g_data->batch_grid, NULL);
     }
   }
 }