VerticalMirroringRenderManager.java 文件源码

private void drawNametable(GGVm ggvm, SpriteBatch spriteBatch, int startingNametableAddress, int scrollX, int scrollY, float splitYStart, float splitYEnd) {
    int patternTable = ggvm.getBackgroundPatternTableAddress() == 0 ? 0 : 1;

    int coarseScrollX = scrollX >> 3;
    int coarseScrollY = scrollY >> 3;
    int fineScrollX = scrollX & 7;
    int fineScrollY = scrollY & 7;

    int nameTableX = coarseScrollX;
    int nameTableY = coarseScrollY;
    int actualNameTableX;
    int actualNameTableY;
    int screenX = 0;
    int screenY = 0;
    int nameTableRowCount = fineScrollY == 0 ? 30 : 31;
    int nameTableColumnCount;
    int nameTable;

    while (nameTableRowCount > 0) {
        screenX = 0;
        nameTableColumnCount = fineScrollX == 0 ? 32 : 33;
        nameTableX = coarseScrollX;
        nameTable = (startingNametableAddress == Ppu.NAME_TABLE_0_BASE_ADDRESS || startingNametableAddress == Ppu.NAME_TABLE_2_BASE_ADDRESS) ? 0 : 1;
        while (nameTableColumnCount > 0) {
            actualNameTableX = nameTableX % 32;
            actualNameTableY = nameTableY % 30;
            int whichNameTable = nameTable ^ ((nameTableX >> 5) & 1);

            int nameTableAddress = whichNameTable == 1 ? Ppu.NAME_TABLE_1_BASE_ADDRESS : Ppu.NAME_TABLE_0_BASE_ADDRESS;
            int attributeTableAddress = whichNameTable == 1 ? Ppu.ATTRIBUTE_TABLE_1_BASE_ADDRESS : Ppu.ATTRIBUTE_TABLE_0_BASE_ADDRESS;

            int index = ggvm.getNametableTile(nameTableAddress, actualNameTableX, actualNameTableY);
            int attribute = ggvm.getAttributeForNametableTile(attributeTableAddress, actualNameTableX, actualNameTableY);

            int indexRow = index >> 4;
            int indexColumn = index & 0x0f;
            Sprite sprite = patternTableManager.getSprite(patternTable, indexRow, indexColumn);//patternTableSprites[patternTableOffset * 16 + indexRow][indexColumn];
            sprite.setColor(0, attributes[attribute], 0, 0);
            if (!GGVmRegisterStatusBar.isSprite0HitStatusBarEnabled() || (screenY >= splitYStart && screenY < splitYEnd)) {
                sprite.setPosition(screenX - fineScrollX, 232 - screenY + fineScrollY);
                sprite.draw(spriteBatch);
            }
            screenX += 8;
            nameTableX++;
            nameTableColumnCount--;
        }
        screenY += 8;
        nameTableY++;
        nameTableRowCount--;
    }
}