[Scummvm-tracker] [ScummVM :: Bugs] #14574: GOB: Excessive blitting drags performance down

[ScummVM :: Bugs]

#14574: GOB: Excessive blitting drags performance down
-----------------------------------+--------------------------
Reporter:  mikrosk                 |       Owner:  sdelamarre
    Type:  defect                  |      Status:  new
Priority:  normal                  |   Component:  Engine: Gob
 Version:                          |  Resolution:
Keywords:  gobliiins, performance  |        Game:  Gobliiins
-----------------------------------+--------------------------
Comment (by mikrosk):

 I might have found both the culprit and fix at the same time.

 {{{
 void Goblin::drawObjects() {
         Util::ListNode *ptr;
         Util::ListNode *ptr2;

         Gob_Object *objDesc;
         Gob_Object *gobDesc2;
         int16 layer;

         ptr = _objList->pHead;
         for (ptr = _objList->pHead; ptr != nullptr; ptr = ptr->pNext) {
                 objDesc = (Gob_Object *)ptr->pData;

                 if (objDesc->type == 3)
                         objDesc->toRedraw = 1;
                 else if (objDesc->type == 1)
                         objDesc->toRedraw = 0;
         }

         for (ptr = _objList->pHead; ptr != nullptr; ptr = ptr->pNext) {
                 objDesc = (Gob_Object *)ptr->pData;
                 if (objDesc->toRedraw == 0)
                         continue;

                 _vm->_draw->_backSurface->blit(*_vm->_mult->_animSurf,
                     objDesc->left, objDesc->top, objDesc->right,
                     objDesc->bottom, objDesc->left, objDesc->top);

                 _vm->_draw->invalidateRect(objDesc->left, objDesc->top,
                     objDesc->right, objDesc->bottom);

                 if (objDesc->type != 0)
                         continue;

                 layer =
 objDesc->stateMach[objDesc->state][objDesc->stateColumn]->
                     layer;
                 _vm->_scenery->updateAnim(layer, objDesc->curFrame,
 objDesc->animation,
                     0, objDesc->xPos, objDesc->yPos, 0);

                 if (_vm->_scenery->_toRedrawLeft == -12345) {
                         objDesc->dirtyLeft = objDesc->left;
                         objDesc->dirtyRight = objDesc->right;
                         objDesc->dirtyTop = objDesc->top;
                         objDesc->dirtyBottom = objDesc->bottom;
                 } else {
                         objDesc->dirtyLeft =
                             MIN(objDesc->left,
 _vm->_scenery->_toRedrawLeft);
                         objDesc->dirtyRight =
                             MAX(objDesc->right,
 _vm->_scenery->_toRedrawRight);
                         objDesc->dirtyTop =
                             MIN(objDesc->top,
 _vm->_scenery->_toRedrawTop);
                         objDesc->dirtyBottom =
                             MAX(objDesc->bottom,
 _vm->_scenery->_toRedrawBottom);
                 }

                 objDesc->dirtyLeft = 0;
                 objDesc->dirtyRight = 319;
                 objDesc->dirtyTop = 0;
                 objDesc->dirtyBottom = 199;
         }
 }}}

 Note how for every object we carefully calculate its dirty rect only to
 overwrite it with a fullscreen update!

 This was there since its 2005 inception and I believe that it is some kind
 of debug leftover. When I remove that override, number of blits is
 decreased from 3700 to 10. :) And visually I couldn't notice any
 difference.
-- 
Ticket URL: <https://bugs.scummvm.org/ticket/14574#comment:8>
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