Base XScreensaver hack or screensaver

README.md

Installation

• Copy base.xml to /usr/share/xscreensaver/config
• Copy the compiled base.c (named "base") to /usr/libexec/xscreensaver
• Add "GL: base -root\n" to programs in .xscreensaver in your home directory.

base.c

/*Compile with:
gcc -pedantic -Wall -Wstrict-prototypes -Wnested-externs -Wmissing-prototypes -Wno-overlength-strings -Wdeclaration-after-statement -std=c89 -U__STRICT_ANSI__ -I../../utils -I../ -I../../ -DSTANDALONE -DUSE_GL -DHAVE_CONFIG_H -g base.c ../fps.c fps-gl.c ../../utils/resources.c ../../utils/visual.c ../../utils/visual-gl.c ../../utils/usleep.c ../../utils/yarandom.c ../../utils/hsv.c ../../utils/colors.c ../../utils/async_netdb.c ../../utils/aligned_malloc.c ../../utils/thread_util.c ../../utils/utf8wc.c ../screenhack.c ../xlockmore.c xlock-gl-utils.c texfont.c -o base -lGL -lGLU -lXxf86vm -lpthread -lSM -lICE -lXft -lXt -lX11 -lXmu -lXext -lm `freetype-config --libs --cflags`

Assuming the current working directory is <xscreensaver directory>/hacks/glx and base.c is stored there.*/

#define DEFAULTS "*delay:        30000\n"\
                 "*showFPS:      False\n"

#include "xlockmore.h"

#ifdef USE_GL
typedef struct {
  GLXContext *glx_context;
} base_configuration;

static base_configuration *confs = NULL;
/*static XrmOptionDescRec opts[] = {};*/
/*static argtype vars[] = {};*/

ENTRYPOINT ModeSpecOpt base_opts = {/*sizeof(opts)/sizeof(XrmOptionDescRec), opts,*/
                                    /*sizeof(vars)/sizeof(argtype), vars,*/
                                    0, NULL,
                                    0, NULL,
                                    NULL};

ENTRYPOINT void reshape_base(ModeInfo *mi, int width, int height) {
    base_configuration* conf = confs + MI_SCREEN(mi);
}

ENTRYPOINT void refresh_base(ModeInfo *mi) {
    base_configuration* conf = confs + MI_SCREEN(mi);
}

ENTRYPOINT void release_base(ModeInfo *mi) {
    base_configuration* conf = confs + MI_SCREEN(mi);
}

ENTRYPOINT Bool base_handle_event(ModeInfo *mi, XEvent *event) {
    base_configuration* conf = confs + MI_SCREEN(mi);
    return False; /*The event was not handled*/
}

ENTRYPOINT void init_base(ModeInfo *mi) {
    base_configuration* conf;
    
    if (!confs)
        confs = malloc(MI_NUM_SCREENS(mi)*sizeof(base_configuration));
    
    if (!confs) {
        fprintf(stderr, "%s: out of memory\n", progname);
        exit(1);
    }
    
    conf = confs + MI_SCREEN(mi);
    
    conf->glx_context = init_GL(mi);
    
    reshape_base(mi, MI_WIDTH(mi), MI_HEIGHT(mi));
}

ENTRYPOINT void draw_base(ModeInfo *mi) {
    base_configuration* conf = confs + MI_SCREEN(mi);
    Display* dpy = MI_DISPLAY(mi);
    Window window = MI_WINDOW(mi);
    
    if (!conf->glx_context)
        return;
    
    glXMakeCurrent(MI_DISPLAY(mi), MI_WINDOW(mi), *(conf->glx_context));
    
    glClearColor(1.0f, 0.5f, 0.5f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);
    
    if (mi->fps_p)
        do_fps(mi);
    
    glFinish();
    glXSwapBuffers(dpy, window);
}

XSCREENSAVER_MODULE("Base", base)
#endif

base.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
<screensaver name="base" _label="Base" gl="yes">
    <command arg="-root"/>
    <number id="delay" type="slider" arg="-delay %"
            _label="Frame rate" _low-label="Low"
            _high-label="High" low="0" high="100000"
            default="30000" convert="invert"/>
    <boolean id="showfps" _label="Show frame rate" arg-set="-fps"/>
    <xscreensaver-updater/>
    <_description>A very basic OpenGL screensaver.</_description>
</screensaver>