glUniform

glUniform is a function in OpenGL that is used to set the value of a uniform variable in a shader program. Uniform variables are special variables in shaders that are shared across all vertices of a vertex shader or all fragments of a fragment shader. They are typically used to pass data from the application to the shader, such as transformation matrices, lighting parameters, or texture samplers.

The glUniform function comes in various forms, differentiated by the type of data they set and the number of components the data has. For example, glUniform1i sets a single integer uniform, glUniform2f sets a uniform with two float components, and glUniformMatrix4fv sets a 4x4 matrix of floats. The first argument to glUniform is always the location of the uniform variable, which is obtained using glGetUniformLocation. The subsequent arguments depend on the specific glUniform function being called and represent the value(s) to be assigned to the uniform. It is crucial to ensure that the data type and number of components passed to glUniform match the declaration of the uniform variable in the shader program. Incorrect usage can lead to undefined behavior or rendering artifacts. Using glUniform is a fundamental part of sending per-frame or per-draw data to shaders for rendering.