I'm trying to make a little addon to forestry that changes the letter and stamp recipes. How would I go about doing that?

 

I have forge set up with a "base mod" and forestry api included in workspace, just no idea where to go form here.

Depends upon what you are trying to do, if you're trying create additional recipes for stamps it's pretty simple, you make like a normal recipe, pulling the stamp id from somewhere

If you're trying to change what Forestry's recipe produce, it's likely not possible

If you want to overwrite a crafting you just need to set the output to ItemStack(0,0)

I have now figured out how to add recipes of my own for the mod items. Is it possible to remove the old ones somehow?

 

If you want to overwrite a crafting you just need to set the output to ItemStack(0,0)

Does this get rid of a recipe? How do I do this?

Well technically no but yes it does and it sets the most recent mod to control it and that is what you wwould do

Do it in your post init method

How do I remove existing recipes exactly? I have this in postinit now, and it only adds a recipe, the removal bit doesn't seem to work.

 

A code snipped showing how to do it would be appreciated.

 

ItemStack letter = new ItemStack(13373,1,0);

RemoveRecipe(letter);

GameRegistry.addShapelessRecipe(letter, paper);
}

private static void RemoveRecipe(ItemStack resultItem) //Code by yope_fried inspired by pigalot
        {
            ItemStack recipeResult = null;
            ArrayList recipes = (ArrayList) CraftingManager.getInstance().getRecipeList();

            for (int i = 0; i < recipes.size(); i++)
            {
                IRecipe tmpRecipe = (IRecipe) recipes.get(i);
                if (tmpRecipe instanceof ShapedRecipes)
                {
                    ShapedRecipes recipe = (ShapedRecipes)tmpRecipe;
                    recipeResult = recipe.getRecipeOutput();
                }

                if (tmpRecipe instanceof ShapelessRecipes)
                {
                    ShapelessRecipes recipe = (ShapelessRecipes)tmpRecipe;
                    recipeResult = recipe.getRecipeOutput();
                }

                if (ItemStack.areItemStacksEqual(resultItem, recipeResult))
                {
                    System.out.println("[YOUR_MOD_NAME] Removed Recipe: " + recipes.get(i) + " -> " + recipeResult);
                    recipes.remove(i);
                }
            }
        }

Ask some mod devs that remove recipes like GregsTech for example

Just go to their website/forum and go to author contact or so and then ask them about it, I know that GregsTech removes the recipe for the MassFabricator in IC2

I shall try, thanks for the answers.