Have we achieved torus?

conway/conway_test.go

@@ -60,7 +60,7 @@ func TestLiveCellWithTwoOrThreeLiveNeighborsLivesOn(t *testing.T) {
 
 	game.EvaluateGeneration()
 
-	cell := game.State.Get(0, 0)
+	cell := game.State.Get(0, 2)
 	if cell.Value != 1 {
 		t.Errorf("%v != 1", cell.Value)
 		return
@@ -262,8 +262,8 @@ func TestGenerationScoreCardCalculateResultsInCorrectNeighborCounts(t *testing.T
 	genScore.Calculate(state)
 
 	cell := genScore.Get(0, 0)
-	if cell.Value != 3 {
-		t.Errorf("[0, 0] value %v != 3", cell.Value)
+	if cell.Value != 4 {
+		t.Errorf("[0, 0] value %v != 4", cell.Value)
 		return
 	}
 

conway/game_state.go

@@ -59,6 +59,10 @@ func (state *GameState) Width() int {
 func (state *GameState) GetRow(y int) *GameStateRow {
 	lenRows := len(state.Rows)
 
+	if y < 0 {
+		return state.GetRow(lenRows + y)
+	}
+
 	if y+1 > lenRows {
 		return state.GetRow(y % lenRows)
 	}
@@ -75,6 +79,10 @@ func (state *GameState) Get(x, y int) *GameStateCell {
 	row := state.GetRow(y)
 	lenCells := len(row.Cells)
 
+	if x < 0 {
+		return state.Get(lenCells+x, row.Y)
+	}
+
 	if x+1 > lenCells {
 		return state.Get(x%lenCells, row.Y)
 	}

conway/generation_score_card.go

@@ -39,7 +39,6 @@ func NewGenerationScoreCard(height, width int) *GenerationScoreCard {
 }
 
 func (genScore *GenerationScoreCard) Calculate(state *GameState) error {
-	stateWidth := state.Width()
 	stateCells, err := state.Cells()
 	if err != nil {
 		return err
@@ -54,14 +53,6 @@ func (genScore *GenerationScoreCard) Calculate(state *GameState) error {
 			xTarget := stateCell.X + neighbor.X
 			yTarget := stateCell.Y + neighbor.Y
 
-			if xTarget < 0 || yTarget < 0 {
-				continue
-			}
-
-			if xTarget+1 > stateWidth || yTarget+1 > stateWidth {
-				continue
-			}
-
 			cell := genScore.Get(xTarget, yTarget)
 			genScore.Set(xTarget, yTarget, cell.Value+1)
 		}