void (GLAPIENTRY *qglReadPixels)(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, GLvoid *pixels);
void (GLAPIENTRY *qglSampleCoverage)(GLclampf value, GLboolean invert);
void (GLAPIENTRY *qglScissor)(GLint x, GLint y, GLsizei width, GLsizei height);
void (GLAPIENTRY *qglReadPixels)(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, GLvoid *pixels);
void (GLAPIENTRY *qglSampleCoverage)(GLclampf value, GLboolean invert);
void (GLAPIENTRY *qglScissor)(GLint x, GLint y, GLsizei width, GLsizei height);