void gl_texgen(GLcontext *ctx, GLint n, GLfloat obj[][4], GLfloat eye[][4], GLfloat normal[][3], GLfloat texcoord[][4])
void gl_texture_pixels(GLcontext *ctx, GLuint n, const GLfloat s[], const GLfloat t[], const GLfloat r[], const GLfloat lambda[], GLubyte red[], GLubyte green[], GLubyte blue[], GLubyte alpha[])
void gl_set_texture_sampler(struct gl_texture_object *t)