I am trying to add textures to my blocks, but they don't load. I don't get missing texture errors in the log.

You're using the wrong version (or the wrong technique for the version you have).

I am using MC 1.7.10.

 

This is the base block class:

package XFactHD.thermalreactors.common.blocks;

import XFactHD.thermalreactors.ThermalReactors;
import XFactHD.thermalreactors.common.util.Reference;

import cofh.api.block.IDismantleable;
import cpw.mods.fml.common.registry.GameRegistry;
import net.minecraft.block.BlockContainer;
import net.minecraft.block.material.Material;
import net.minecraft.client.renderer.texture.IIconRegister;
import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.entity.EnumCreatureType;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.util.IIcon;
import net.minecraft.world.IBlockAccess;
import net.minecraft.world.World;

import java.util.ArrayList;
import java.util.List;

public abstract class BlockBaseTR extends BlockContainer implements IDismantleable
{
    public String name;
    public String[] subNames;
    public final IIcon[][] icons;

    public BlockBaseTR(String name, Material mat, int iconDimensions, Class<? extends ItemBlockBaseTR> itemblock, String... subNames)
    {
        super(mat);
        this.subNames = subNames;
        this.name = name;
        this.icons = new IIcon[subNames.length][iconDimensions];
        this.setBlockName(Reference.MOD_ID + ":" + name);
        GameRegistry.registerBlock(this, itemblock, name);
        this.setCreativeTab(ThermalReactors.creativeTab);
    }

    @Override
    public int damageDropped(int meta)
    {
        return meta;
    }
    @Override
    public void getSubBlocks(Item item, CreativeTabs tab, List list)
    {
        for(int i=0; i<subNames.length; i++)
        {
            list.add(new ItemStack(item, 1, i));
        }
    }

    @Override
    public void registerBlockIcons(IIconRegister iconRegister)
    {
        for(int i=0;i<subNames.length;i++)
            icons[i][0] = iconRegister.registerIcon(Reference.MOD_ID + ":" + name + "_" + subNames[i]);
    }

    @Override
    public boolean canCreatureSpawn(EnumCreatureType type, IBlockAccess world, int x, int y, int z)
    {
        return false;
    }

    @Override
    public boolean canDismantle(EntityPlayer entityPlayer, World world, int i, int i1, int i2)
    {
        return false;
    }

    @Override
    public ArrayList<ItemStack> dismantleBlock(EntityPlayer entityPlayer, World world, int x, int y, int z, boolean b)
    {
        return null;
    }
}

This is one of the extending block classes:

package XFactHD.thermalreactors.common.blocks.stone;

import XFactHD.thermalreactors.common.blocks.BlockSimpleTR;
import XFactHD.thermalreactors.common.blocks.ItemBlockBaseTR;

import net.minecraft.block.material.Material;

public class BlockOre extends BlockSimpleTR
{
    public BlockOre()
    {
        super("ore", Material.rock, ItemBlockBaseTR.class, "Uranium", "Zirconium");
        setHardness(0.5F);
    }
}

But I am using the registerBlockIcons() method:

    @Override
    public void registerBlockIcons(IIconRegister iconRegister)
    {
        for(int i=0;i<subNames.length;i++)
            icons[i][0] = iconRegister.registerIcon(Reference.MOD_ID + ":" + name + "_" + subNames[i]);
    }

Or is that what you mean by "filling the array"?

OK, I am going to try that out and report back afterwards.

You're using the wrong version (or the wrong technique for the version you have).

How can you know? There is no information provided at all.

Exactly, which I took as license to use my imagination. I imagined that the author had watched the wrong tutorial for the Forge version he had.

 

Instead, it looks like he just missed a step. I think that each simple block in 1.7 needs to call setBlockTextureName. However, a block with subtypes has needs to override getIcon instead:

 

  @Override
  @SideOnly(Side.CLIENT)
  public IIcon getIcon(int side, int meta) {...}

I got it working now. Thank you for your help.