extern void (GLAPIENTRY *qglVertexAttrib4usv)(GLuint index, const GLushort *v);
extern void (GLAPIENTRY *qglVertexAttribPointer)(GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride, const GLvoid *pointer);
extern void (GLAPIENTRY *qglViewport)(GLint x, GLint y, GLsizei width, GLsizei height);
extern void (GLAPIENTRY *qglVertexAttrib4usv)(GLuint index, const GLushort *v);
extern void (GLAPIENTRY *qglVertexAttribPointer)(GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride, const GLvoid *pointer);
extern void (GLAPIENTRY *qglViewport)(GLint x, GLint y, GLsizei width, GLsizei height);