blend

Combining a newly drawn pixel with the color already on screen, as for transparency.

Blending mixes a fragment's color with the existing framebuffer color according to a formula, which is how effects like transparency, glow, and anti-aliased edges are achieved. Parameters such as blend constants (set via vkCmdSetBlendConstants in Vulkan) tune the mix. Without blending, each drawn pixel would simply overwrite whatever was underneath.