Alpha mapping

Alpha mapping is like painting on paper with different colors and using a stencil to control where you put the colors. Imagine you have a picture of a tree and you want to color in the leaves with green, but you don't want to color the trunk. You can use a stencil, which is like a piece of paper with a hole cut out in the shape of the leaves. You place the stencil over the tree and color in the leaves only, not the trunk. Alpha mapping works in a similar way, but instead of using a physical stencil, you use a special type of image called an alpha map. This image has different levels of transparency which tell the computer where to apply a certain effect or color. So, just like the stencil, the alpha map controls where the effect or color is applied. It's like having a magical paintbrush that only colors specific parts of a picture.