glGetBooleanvGLenum

glGetBooleanv is a function in the OpenGL API used to query the current values of various OpenGL boolean state variables. It takes two arguments: a parameter enum and a pointer to a boolean array. The parameter enum specifies which state variable to query, and the pointer will be filled with the current value of that state variable.

Commonly queried parameters include GL_ALPHA_TEST, GL_BLEND, GL_CULL_FACE, GL_DEPTH_TEST, GL_LIGHTING, GL_LOGIC_OP, GL_SCISSOR_TEST, and GL_STENCIL_TEST. These parameters indicate whether certain rendering features are currently enabled or disabled. For example, querying GL_DEPTH_TEST with glGetBooleanv will return GL_TRUE if depth testing is enabled and GL_FALSE if it is disabled.

The boolean values returned are either GL_TRUE or GL_FALSE. The size of the boolean array required depends on the queried parameter. Some parameters, like GL_ALPHA_TEST, return a single boolean value, requiring an array of size 1. Others, like GL_VIEWPORT, might return multiple values, although glGetBooleanv is specifically for boolean states. If a parameter can return multiple values, it will usually be represented as an array of booleans.

The glGetBooleanv function is crucial for debugging and for dynamically adjusting rendering behavior based on the current OpenGL state. It allows applications to check the status of various OpenGL features and modify their rendering pipeline accordingly without needing to manually track these states themselves.