ModifyConstant

Danger

ModifyConstant should not be used as they cause hard conflicts with any other mods trying to change the same constant. They can always be replaced with a ModifyExpressionValue.

This type of injection should never be used unless you want your mod to be incompatible with other mods. ModifyConstant allows easy editing of a constant anywhere in a method.

Say we had the following code:

public void foo() {
    int x = this.getWidth() + 5;
    int y = this.getHeight() + 10;
    drawTexture(x, y);
    drawTexture2(x - 20, y - 20);
}

If we wanted to translate both the textures along the y, we could simply do so by modifying the constant from the + 5:

@ModifyConstant(method = "foo", constant = @Constant(intValue = 5))
private int changeConstant(int original) {
    return 15;
}

To result in:

public void foo() {
    int x = this.getWidth() + 15;
    int y = this.getHeight() + 10;
    drawTexture(x, y);
    drawTexture2(x - 20, y - 20);
}

This example could obviously be solved in many different ways as well, but ModifyConstant also allows us to modify numbers that would usually be difficult to target.

Say we had a for loop as so:

for (int i = 0; i < 10; i++) {
    ...
}

We could use a ModifyConstant here to target the intValue 10 to change it to whatever we wanted.