fixed all gocognit lint errors (#848)

* reduced ItemFactory.NewItem complexity

* d2compression/wav.go: suppressing gocognit lint error, suppressing gocyclo lint error

* d2maprenderer/renderer.go: reducing complexity of rnderPass2 and renderPass3

d2common/d2data/d2compression/wav.go

@@ -6,7 +6,7 @@ import (
 
 // WavDecompress decompresses wav files
 //nolint:gomnd // binary decode magic
-func WavDecompress(data []byte, channelCount int) []byte { //nolint:funlen // can't reduce
+func WavDecompress(data []byte, channelCount int) []byte { //nolint:funlen,gocognit,gocyclo // can't reduce
 	Array1 := []int{0x2c, 0x2c}
 	Array2 := make([]int, channelCount)
 

d2core/d2item/diablo2item/item_factory.go

@@ -82,11 +82,9 @@ func (f *ItemFactory) SetSeed(seed int64) {
 
 // NewItem creates a new item instance from the given codes
 func (f *ItemFactory) NewItem(codes ...string) (*Item, error) {
-	var item *Item
-
 	var common, set, unique string
 
-	var prefixes, suffixes []string
+	prefixes, suffixes := make([]string, 0), make([]string, 0)
 
 	for _, code := range codes {
 		if found := f.asset.Records.Item.All[code]; found != nil {
@@ -105,28 +103,24 @@ func (f *ItemFactory) NewItem(codes ...string) (*Item, error) {
 		}
 
 		if found := f.asset.Records.Item.Magic.Prefix[code]; found != nil {
-			if prefixes == nil {
-				prefixes = make([]string, 0)
-			}
-
 			prefixes = append(prefixes, code)
-
 			continue
 		}
 
 		if found := f.asset.Records.Item.Magic.Suffix[code]; found != nil {
-			if suffixes == nil {
-				suffixes = make([]string, 0)
-			}
-
 			suffixes = append(suffixes, code)
-
 			continue
 		}
 	}
 
-	if common != "" { // we will at least have a regular item
+	if common == "" {
-		item = &Item{CommonCode: common}
+		return nil, errors.New("cannot create item")
+	}
+
+	item := &Item{
+		factory:    f,
+		CommonCode: common,
+	}
 
 	if set != "" { // it's a set item
 		item.SetItemCode = set
@@ -138,24 +132,15 @@ func (f *ItemFactory) NewItem(codes ...string) (*Item, error) {
 		return item.init(), nil
 	}
 
-		if prefixes != nil {
+	if len(prefixes) > 0 {
-			if len(prefixes) > 0 { // it's a magic or rare item
 		item.PrefixCodes = prefixes
 	}
-		}
 
-		if suffixes != nil {
+	if len(suffixes) > 0 {
-			if len(suffixes) > 0 { // it's a magic or rare item
 		item.SuffixCodes = suffixes
 	}
-		}
-
-		item.factory = f
 
 	return item.init(), nil
-	}
-
-	return nil, errors.New("cannot create item")
 }
 
 // NewProperty creates a property

d2core/d2map/d2maprenderer/renderer.go

@@ -206,25 +206,7 @@ func (mr *MapRenderer) renderPass2(target d2interface.Surface, startX, startY, e
 		for tileX := startX; tileX < endX; tileX++ {
 			mr.viewport.PushTranslationWorld(float64(tileX), float64(tileY))
 
-			tileEnt := make([]d2interface.MapEntity, 0)
+			tileEnt := mr.getEntitiesBelowWalls(tileX, tileY)
-
-			// need to add render culling
-			// https://github.com/OpenDiablo2/OpenDiablo2/issues/821
-			for _, mapEntity := range mr.mapEngine.Entities() {
-				pos := mapEntity.GetPosition()
-				vec := pos.World()
-				entityX, entityY := vec.X(), vec.Y()
-
-				if mapEntity.GetLayer() != 1 {
-					continue
-				}
-
-				if (int(entityX) != tileX) || (int(entityY) != tileY) {
-					continue
-				}
-
-				tileEnt = append(tileEnt, mapEntity)
-			}
 
 			for subY := 0; subY < 5; subY++ {
 				for subX := 0; subX < 5; subX++ {
@@ -246,15 +228,8 @@ func (mr *MapRenderer) renderPass2(target d2interface.Surface, startX, startY, e
 	}
 }
 
-// Upper wall tiles and entities above walls.
+func (mr *MapRenderer) getEntitiesBelowWalls(tileX, tileY int) []d2interface.MapEntity {
-func (mr *MapRenderer) renderPass3(target d2interface.Surface, startX, startY, endX, endY int) {
+	entities := make([]d2interface.MapEntity, 0)
-	for tileY := startY; tileY < endY; tileY++ {
-		for tileX := startX; tileX < endX; tileX++ {
-			tile := mr.mapEngine.TileAt(tileX, tileY)
-			mr.viewport.PushTranslationWorld(float64(tileX), float64(tileY))
-			mr.renderTilePass2(tile, target)
-
-			tileEnt := make([]d2interface.MapEntity, 0)
 
 	// need to add render culling
 	// https://github.com/OpenDiablo2/OpenDiablo2/issues/821
@@ -263,7 +238,7 @@ func (mr *MapRenderer) renderPass3(target d2interface.Surface, startX, startY, e
 		vec := pos.World()
 		entityX, entityY := vec.X(), vec.Y()
 
-				if mapEntity.GetLayer() == 1 {
+		if mapEntity.GetLayer() != 1 {
 			continue
 		}
 
@@ -271,19 +246,32 @@ func (mr *MapRenderer) renderPass3(target d2interface.Surface, startX, startY, e
 			continue
 		}
 
-				tileEnt = append(tileEnt, mapEntity)
+		entities = append(entities, mapEntity)
 	}
 
+	return entities
+}
+
+// Upper wall tiles and entities above walls.
+func (mr *MapRenderer) renderPass3(target d2interface.Surface, startX, startY, endX, endY int) {
+	for tileY := startY; tileY < endY; tileY++ {
+		for tileX := startX; tileX < endX; tileX++ {
+			tile := mr.mapEngine.TileAt(tileX, tileY)
+			mr.viewport.PushTranslationWorld(float64(tileX), float64(tileY))
+			mr.renderTilePass2(tile, target)
+
+			entities := mr.getEntitiesAboveWalls(tileX, tileY)
+
 			for subY := 0; subY < 5; subY++ {
 				for subX := 0; subX < 5; subX++ {
-					for _, mapEntity := range tileEnt {
+					for _, entity := range entities {
-						pos := mapEntity.GetPosition()
+						pos := entity.GetPosition()
 						if (int(pos.SubTileOffset().X()) != subX) || (int(pos.SubTileOffset().Y()) != subY) {
 							continue
 						}
 
 						target.PushTranslation(mr.viewport.GetTranslationScreen())
-						mapEntity.Render(target)
+						entity.Render(target)
 						target.Pop()
 					}
 				}
@@ -294,6 +282,30 @@ func (mr *MapRenderer) renderPass3(target d2interface.Surface, startX, startY, e
 	}
 }
 
+func (mr *MapRenderer) getEntitiesAboveWalls(tileX, tileY int) []d2interface.MapEntity {
+	entities := make([]d2interface.MapEntity, 0)
+
+	// need to add render culling
+	// https://github.com/OpenDiablo2/OpenDiablo2/issues/821
+	for _, mapEntity := range mr.mapEngine.Entities() {
+		pos := mapEntity.GetPosition()
+		vec := pos.World()
+		entityX, entityY := vec.X(), vec.Y()
+
+		if mapEntity.GetLayer() != 1 {
+			continue
+		}
+
+		if (int(entityX) != tileX) || (int(entityY) != tileY) {
+			continue
+		}
+
+		entities = append(entities, mapEntity)
+	}
+
+	return entities
+}
+
 // Roof tiles.
 func (mr *MapRenderer) renderPass4(target d2interface.Surface, startX, startY, endX, endY int) {
 	for tileY := startY; tileY < endY; tileY++ {