glColor4f

glColor4f is a function in the OpenGL graphics library used to set the current color with red, green, blue, and alpha components. The 'f' at the end of glColor4f indicates that the color components are specified as floating-point numbers. Each component ranges from 0.0 to 1.0, where 0.0 represents no intensity and 1.0 represents full intensity. For example, glColor4f(1.0f, 0.0f, 0.0f, 1.0f) would set the current color to opaque red. glColor4f(0.0f, 1.0f, 0.0f, 0.5f) would set the current color to semi-transparent green.

This function affects all subsequent drawing operations until it is called again. It influences the color of vertices, pixels, and other graphical primitives. The alpha component controls the opacity of the color, with 1.0 being fully opaque and 0.0 being fully transparent. When alpha is less than 1.0, the color will blend with the background according to the current blending mode.

glColor4f is part of the OpenGL API and is available across various platforms and programming languages that interface with OpenGL. It is fundamental for defining the visual appearance of objects rendered in a 3D scene or 2D graphics. The function is typically used before specifying vertex coordinates or issuing drawing commands.