xscreensaver 6.00v28r1openslx

13 files changed, 484 insertions, 189 deletions

diff --git a/jwxyz/Makefile.in b/jwxyz/Makefile.in
index 0ba48a6..1f6d6ae 100644
--- a/jwxyz/Makefile.in
+++ b/jwxyz/Makefile.in
@@ -1,4 +1,4 @@
-# utils/Makefile.in --- xscreensaver, Copyright (c) 1997-2010 Jamie Zawinski.
+# utils/Makefile.in --- xscreensaver, Copyright © 1997-2021 Jamie Zawinski.
 # the `../configure' script generates `jwxyz/Makefile' from this file.
 
 # JWXYZ Is Not Xlib.
@@ -97,8 +97,8 @@ TAGS: tags
 tags:
 	find $(srcdir) -name '*.[chly]' -print | xargs etags -a
 
-echo_tarfiles:
-	@echo $(TARFILES)
+list_tarfiles:
+	@find $(TARFILES) -type f -print | sort
 
 
 # How we build object files in this directory.
@@ -106,30 +106,6 @@ echo_tarfiles:
 	$(CC) -c $(INCLUDES) $(DEFS) $(CPPFLAGS) $(CFLAGS) $(X_CFLAGS) $<
 
 
-# Rules for generating the VMS makefiles on Unix, so that it doesn't have to
-# be done by hand...
-#
-VMS_AXP_COMPILE=$$ CC/DECC/PREFIX=ALL/DEFINE=(VMS,HAVE_CONFIG_H)/INCL=([],[-])
-
-compile_axp.com: Makefile.in
-	@echo generating $@ from $<...  ;				    \
-	( ( for c in $(SRCS) vms-*.c ; do				    \
-	      c=`echo $$c | tr a-z A-Z` ;				    \
-	      echo "$(VMS_AXP_COMPILE) $$c" ;				    \
-            done ;							    \
-	  ) | sort -d ;							    \
-          echo '$$ lib/cre utils.olb_axp' ; 				    \
-	  echo '$$ lib utils.olb_axp *.obj' ; 				    \
-	  echo '$$! delete/noconf *.obj;' ; 				    \
-        ) > $@
-
-compile_decc.com: compile_axp.com
-	@echo generating $@ from $<...  ;				    \
-	sed 's/axp/decc/g' < $< > $@
-
-distdepend:: compile_axp.com compile_decc.com
-
-
 ##############################################################################
 #
 # DO NOT DELETE: updated by make distdepend
diff --git a/jwxyz/jwxyz-android.c b/jwxyz/jwxyz-android.c
index 85ce924..c84028b 100644
--- a/jwxyz/jwxyz-android.c
+++ b/jwxyz/jwxyz-android.c
@@ -1,4 +1,4 @@
-/* xscreensaver, Copyright (c) 2016-2018 Jamie Zawinski <jwz@jwz.org>
+/* xscreensaver, Copyright © 2016-2021 Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -7,13 +7,19 @@
  * documentation.  No representations are made about the suitability of this
  * software for any purpose.  It is provided "as is" without express or 
  * implied warranty.
- *
- * This file is three related things:
- *
- *   - It is the Android-specific C companion to jwxyz-gl.c;
- *   - It is how C calls into Java to do things that OpenGL does not
- *     have access to without Java-based APIs;
- *   - It is how the jwxyz.java class calls into C to run the hacks.
+ */
+
+/* JWXYZ Is Not Xlib.
+
+   See the comment at the top of jwxyz-common.c for an explanation of
+   the division of labor between these various modules.
+
+   This file is three related things:
+  
+     - It is the Android-specific companion to jwxyz-gl.c or jwxyz-image.c;
+     - It is how C calls into Java to do things that OpenGL does not have
+       access to without Java-based APIs;
+     - It is how the jwxyz.java class calls into C to run the hacks.
  */
 
 #ifdef HAVE_ANDROID /* whole file */
@@ -25,8 +31,13 @@
 #include <math.h>
 #include <setjmp.h>
 
+#define GL_GLEXT_PROTOTYPES
+
 #include <GLES/gl.h>
 #include <GLES/glext.h>
+#ifdef HAVE_GLES3
+# include <GLES3/gl3.h>
+#endif
 #include <jni.h>
 #include <android/bitmap.h>
 #include <android/log.h>
@@ -228,6 +239,202 @@ prepare_context (struct running_hack *rh)
 }
 
 
+static void
+get_egl_config_android(Window window, EGLDisplay *egl_display,
+                       EGLConfig *egl_config)
+{
+# define R EGL_RED_SIZE
+# define G EGL_GREEN_SIZE
+# define B EGL_BLUE_SIZE
+# define A EGL_ALPHA_SIZE
+# define D EGL_DEPTH_SIZE
+# define I EGL_BUFFER_SIZE
+# define ST EGL_STENCIL_SIZE
+  EGLint templates[][40] = {
+    { R,8, G,8, B,8, A,8, D,8, ST,1, EGL_NONE }, /* rgba stencil */
+    { R,8, G,8, B,8,      D,8, ST,1, EGL_NONE }, /* rgb  stencil */
+    { R,4, G,4, B,4,      D,4, ST,1, EGL_NONE },
+    { R,2, G,2, B,2,      D,2, ST,1, EGL_NONE },
+    { R,8, G,8, B,8, A,8, D,8,       EGL_NONE }, /* rgba */
+    { R,8, G,8, B,8,      D,8,       EGL_NONE }, /* rgb  */
+    { R,4, G,4, B,4,      D,4,       EGL_NONE },
+    { R,2, G,2, B,2,      D,2,       EGL_NONE },
+    { R,1, G,1, B,1,      D,1,       EGL_NONE }  /* monochrome */
+  };
+  EGLint attrs[40];
+  EGLint nconfig;
+  int i, j, k, iter, pass;
+
+  char *glsls = get_string_resource_window (window, "prefersGLSL");
+  Bool glslp = (glsls && !strcasecmp(glsls, "true"));
+  iter = (glslp ? 2 : 1);
+
+  *egl_config = 0;
+  for (pass = 0; pass < iter; pass++)
+    {
+      for (i = 0; i < countof(templates); i++)
+        {
+          for (j = 0, k = 0; templates[i][j] != EGL_NONE; j += 2)
+            {
+              attrs[k++] = templates[i][j];
+              attrs[k++] = templates[i][j+1];
+            }
+
+          attrs[k++] = EGL_RENDERABLE_TYPE;
+# ifdef HAVE_GLES3
+          if (glslp && pass == 0)
+            attrs[k++] = EGL_OPENGL_ES3_BIT;
+          else
+            attrs[k++] = EGL_OPENGL_ES_BIT;
+# else
+          attrs[k++] = EGL_OPENGL_ES_BIT;
+# endif
+
+          attrs[k++] = EGL_NONE;
+
+          nconfig = -1;
+          if (eglChooseConfig (egl_display, attrs, egl_config, 1, &nconfig)
+              && nconfig == 1)
+            break;
+        }
+      if (i < countof(templates))
+        break;
+    }
+  Assert (*egl_config != 0, "no EGL config chosen");
+#if 1
+  {
+    int i;
+    const struct { int hexp; EGLint i; const char *s; } fields[] = {
+      { 1, EGL_CONFIG_ID,		"config ID:"	 },
+      { 1, EGL_CONFIG_CAVEAT,		"caveat:"	 },
+      { 1, EGL_CONFORMANT,		"conformant:"	 },
+      { 0, EGL_COLOR_BUFFER_TYPE,	"buffer type:"	 },
+      { 0, EGL_RED_SIZE,		"color size:"	 },
+      { 0, EGL_TRANSPARENT_RED_VALUE,	"transparency:"	 },
+      { 0, EGL_BUFFER_SIZE,		"buffer size:"	 },
+      { 0, EGL_DEPTH_SIZE,		"depth size:"	 },
+      { 0, EGL_LUMINANCE_SIZE,	"lum size:"	 },
+      { 0, EGL_STENCIL_SIZE,		"stencil size:"	 },
+      { 0, EGL_ALPHA_MASK_SIZE,	"alpha mask:"	 },
+      { 0, EGL_LEVEL,			"level:"	 },
+      { 0, EGL_SAMPLES,		"samples:"	 },
+      { 0, EGL_SAMPLE_BUFFERS,	"sample bufs:"	 },
+      { 0, EGL_NATIVE_RENDERABLE,	"native render:" },
+      { 1, EGL_NATIVE_VISUAL_TYPE,	"native type:"	 },
+      { 1, EGL_RENDERABLE_TYPE,	"render type:"	 },
+      { 0, EGL_SURFACE_TYPE,		"surface type:"	 },
+      { 0, EGL_BIND_TO_TEXTURE_RGB,	"bind RGB:"	 },
+      { 0, EGL_BIND_TO_TEXTURE_RGBA,	"bind RGBA:"	 },
+      { 0, EGL_MAX_PBUFFER_WIDTH,	"buffer width:"	 },
+      { 0, EGL_MAX_PBUFFER_HEIGHT,	"buffer height:" },
+      { 0, EGL_MAX_PBUFFER_PIXELS,	"buffer pixels:" },
+      { 0, EGL_MAX_SWAP_INTERVAL,	"max swap:"	 },
+      { 0, EGL_MIN_SWAP_INTERVAL,	"min swap:"	 },
+    };
+    EGLint r=0, g=0, b=0, a=0, tt=0, tr=0, tg=0, tb=0;
+    eglGetConfigAttrib (egl_display, *egl_config, EGL_RED_SIZE,   &r);
+    eglGetConfigAttrib (egl_display, *egl_config, EGL_GREEN_SIZE, &g);
+    eglGetConfigAttrib (egl_display, *egl_config, EGL_BLUE_SIZE,  &b);
+    eglGetConfigAttrib (egl_display, *egl_config, EGL_ALPHA_SIZE, &a);
+    eglGetConfigAttrib (egl_display, *egl_config,
+                        EGL_TRANSPARENT_TYPE, &tt);
+    eglGetConfigAttrib (egl_display, *egl_config,
+                        EGL_TRANSPARENT_RED_VALUE,  &tr);
+    eglGetConfigAttrib (egl_display, *egl_config,
+                        EGL_TRANSPARENT_GREEN_VALUE,&tg);
+    eglGetConfigAttrib (egl_display, *egl_config,
+                        EGL_TRANSPARENT_BLUE_VALUE, &tb);
+    for (i = 0; i < countof(fields); i++)
+      {
+        EGLint v = 0;
+        char s[100];
+        eglGetConfigAttrib (egl_display, *egl_config, fields[i].i, &v);
+        if (fields[i].i == EGL_RED_SIZE)
+          sprintf (s, "%d, %d, %d, %d", r, g, b, a);
+        else if (fields[i].i == EGL_TRANSPARENT_RED_VALUE && tt != EGL_NONE)
+          sprintf (s, "%d, %d, %d", tr, tg, tb);
+        else if (fields[i].i == EGL_CONFIG_CAVEAT)
+          strcpy (s, (v == EGL_NONE ? "none" :
+                      v == EGL_SLOW_CONFIG ? "slow" :
+# ifdef EGL_NON_CONFORMANT
+                      v == EGL_NON_CONFORMANT ? "non-conformant" :
+# endif
+                      "???"));
+        else if (fields[i].i == EGL_COLOR_BUFFER_TYPE)
+          strcpy (s, (v == EGL_RGB_BUFFER ? "RGB" :
+                      v == EGL_LUMINANCE_BUFFER ? "luminance" :
+                      "???"));
+        else if (fields[i].i == EGL_CONFORMANT ||
+                 fields[i].i == EGL_RENDERABLE_TYPE)
+          {
+            sprintf (s, "0x%02x", v);
+            if (v & EGL_OPENGL_BIT)     strcat (s, " OpenGL");
+            if (v & EGL_OPENGL_ES_BIT)  strcat (s, " GLES-1.x");
+            if (v & EGL_OPENGL_ES2_BIT) strcat (s, " GLES-2.0");
+# ifdef EGL_OPENGL_ES3_BIT
+            if (v & EGL_OPENGL_ES3_BIT) strcat (s, " GLES-3.0");
+# endif
+            if (v & EGL_OPENVG_BIT)     strcat (s, " OpenVG");
+          }
+        else if (fields[i].hexp)
+          sprintf (s, "0x%02x", v);
+        else if (v)
+          sprintf (s, "%d", v);
+        else
+          *s = 0;
+
+        if (*s) Log ("init:    EGL %-14s %s\n", fields[i].s, s);
+      }
+  }
+#endif
+}
+
+
+static void
+get_egl_context_android(Window window, EGLDisplay *egl_display,
+                        EGLConfig *egl_config, EGLContext *egl_context)
+{
+  EGLint context_attribs[][3] = {
+    { EGL_CONTEXT_CLIENT_VERSION, 1, EGL_NONE },
+    { EGL_CONTEXT_CLIENT_VERSION, 3, EGL_NONE }
+  };
+  EGLint *attrs;
+  Bool glslp;
+  int pass, iter;
+
+# ifdef EGL_OPENGL_ES3_BIT
+  char *glsls = get_string_resource_window (window, "prefersGLSL");
+  glslp = (glsls && !strcasecmp(glsls, "true"));
+  if (glslp)
+    {
+      EGLint renderable_type;
+      eglGetConfigAttrib (egl_display, egl_config, EGL_RENDERABLE_TYPE,
+                          &renderable_type);
+      Bool gles3p = (renderable_type & EGL_OPENGL_ES3_BIT) != 0;
+      glslp = glslp && gles3p;
+    }
+# else
+  glslp = False;
+# endif
+  iter = (glslp ? 2 : 1);
+
+  *egl_context = EGL_NO_CONTEXT;
+  for (pass = 0; pass < iter; pass++)
+    {
+      if (glslp && pass == 0)
+        attrs = context_attribs[1];
+      else
+        attrs = context_attribs[0];
+      *egl_context = eglCreateContext (egl_display, egl_config,
+                                       EGL_NO_CONTEXT, attrs);
+      if (*egl_context != EGL_NO_CONTEXT)
+        break;
+    }
+
+  Assert (*egl_context != EGL_NO_CONTEXT, "init: EGL_NO_CONTEXT");
+}
+
+
 // Initialized OpenGL and runs the screenhack's init function.
 //
 static void
@@ -344,7 +551,24 @@ doinit (jobject jwxyz_obj, struct running_hack *rh, JNIEnv *env,
 
   /* Note: https://source.android.com/devices/graphics/arch-egl-opengl */
 
-  /* ####: This is lame, use a resource. */
+  /* jwxyz_gl_p controls which implementation of Pixmaps we are using.
+
+     - jwxyz-image.c implements them in CPU RAM, and is used for Android GL
+       hacks, and for kumppa, petri and slip, which are too slow otherwise.
+
+     - jwxyz-gl.c implements them in terms of OpenGL textures, and is used
+       for all other Android X11 hacks.
+
+     Why two implemementations of Pixmaps for Android?
+
+     - GL hacks don't tend to need much in the way of Xlib, and having a
+       GL context to render Xlib alongside a GL context for rendering GL
+       seemed like trouble.
+
+     - X11 hacks render to a GL context because hardware acceleration tends
+       to work well with Xlib geometric stuff.  Better framerates, lower
+       power.
+   */
   rh->jwxyz_gl_p =
     rh->xsft->visual == DEFAULT_VISUAL &&
     strcmp (progname, "kumppa") &&
@@ -357,48 +581,27 @@ doinit (jobject jwxyz_obj, struct running_hack *rh, JNIEnv *env,
 
   rh->egl_p = rh->jwxyz_gl_p || rh->xsft->visual == GL_VISUAL;
 
+  int egl_major = -1, egl_minor = -1;
+
   if (rh->egl_p) {
   // GL init. Must come after resource processing.
 
     rh->egl_display = eglGetDisplay (EGL_DEFAULT_DISPLAY);
     Assert (rh->egl_display != EGL_NO_DISPLAY, "init: EGL_NO_DISPLAY");
 
-    int egl_major, egl_minor;
     Assert (eglInitialize (rh->egl_display, &egl_major, &egl_minor),
             "eglInitialize failed");
 
-    // TODO: Skip depth and (probably) alpha for Xlib.
-    // TODO: Could ask for EGL_SWAP_BEHAVIOR_PRESERVED_BIT here...maybe?
-    // TODO: Probably should try to ask for EGL_PBUFFER_BIT.
-    // TODO: Do like visual-gl.c and work from a list of configs.
-    /* Probably don't need EGL_FRAMEBUFFER_TARGET_ANDROID here if GLSurfaceView
-       doesn't use it.
-     */
-    EGLint config_attribs[] = {
-       EGL_RED_SIZE, 8,
-       EGL_GREEN_SIZE, 8,
-       EGL_BLUE_SIZE, 8,
-       EGL_ALPHA_SIZE, 8,
-       EGL_DEPTH_SIZE, 16,
-       EGL_NONE
-    };
-
-    EGLint num_config;
-    Assert (eglChooseConfig (rh->egl_display, config_attribs,
-                             &rh->egl_config, 1, &num_config),
-            "eglChooseConfig failed");
-    Assert (num_config == 1, "no EGL config chosen");
+    get_egl_config_android (rh->window, rh->egl_display, &rh->egl_config);
 
-    EGLint no_attribs[] = {EGL_NONE};
-    rh->egl_ctx = eglCreateContext (rh->egl_display, rh->egl_config,
-                                    EGL_NO_CONTEXT, no_attribs);
-    Assert (rh->egl_ctx != EGL_NO_CONTEXT, "init: EGL_NO_CONTEXT");
+    get_egl_context_android(rh->window, rh->egl_display, rh->egl_config,
+                            &rh->egl_ctx);
 
     ANativeWindow *native_window =
       ANativeWindow_fromSurface (env, jni_surface);
 
     rh->egl_surface = eglCreateWindowSurface (rh->egl_display, rh->egl_config,
-                                              native_window, no_attribs);
+                                              native_window, NULL);
     Assert (rh->egl_surface != EGL_NO_SURFACE, "init: EGL_NO_SURFACE");
 
     ANativeWindow_release (native_window);
@@ -423,10 +626,12 @@ doinit (jobject jwxyz_obj, struct running_hack *rh, JNIEnv *env,
   prepare_context (rh);
 
   if (rh->egl_p) {
-    Log ("init %s / %s / %s",
+    // GL_SHADING_LANGUAGE_VERSION undefined
+    Log ("init %s / %s / %s / EGL %d.%d",
          glGetString (GL_VENDOR),
          glGetString (GL_RENDERER),
-         glGetString (GL_VERSION));
+         glGetString (GL_VERSION),
+         egl_major, egl_minor);
   }
 
   if (rh->jwxyz_gl_p) {
@@ -487,10 +692,7 @@ doinit (jobject jwxyz_obj, struct running_hack *rh, JNIEnv *env,
 
   } else {
 
-    if (rh->xsft->visual == DEFAULT_VISUAL)
-      create_pixmap (wnd, wnd);
-    else
-      wnd->image_data = NULL;
+    create_pixmap (wnd, wnd);
 
     static const unsigned char rgba_bytes[] = {0, 1, 2, 3};
     rh->dpy = jwxyz_image_make_display(wnd, rgba_bytes);
@@ -597,7 +799,6 @@ drawXScreenSaver (JNIEnv *env, struct running_hack *rh)
       if (! rh->xsft->fps_cb) rh->xsft->fps_cb = screenhack_do_fps;
     } else {
       rh->fpst = NULL;
-      rh->xsft->fps_cb = 0;
     }
 
     if ((*env)->ExceptionOccurred(env)) abort();
@@ -834,7 +1035,7 @@ Java_org_jwz_xscreensaver_jwxyz_nativeResize (JNIEnv *env, jobject thiz,
     }
 
     jwxyz_window_resized (rh->dpy);
-  } else if (rh->xsft->visual == DEFAULT_VISUAL) {
+  } else {
     free_pixmap (rh, wnd);
     create_pixmap (wnd, wnd);
     XClearWindow (rh->dpy, wnd); // TODO: This is lame. Copy the bits.
@@ -877,6 +1078,8 @@ Java_org_jwz_xscreensaver_jwxyz_nativeDone (JNIEnv *env, jobject thiz)
 
   prepare_context (rh);
 
+  if (rh->fpst)
+    rh->xsft->fps_free (rh->fpst);
   if (rh->initted_p)
     rh->xsft->free_cb (rh->dpy, rh->window, rh->closure);
   if (rh->jwxyz_gl_p)
@@ -897,8 +1100,7 @@ Java_org_jwz_xscreensaver_jwxyz_nativeDone (JNIEnv *env, jobject thiz)
     eglDestroyContext (rh->egl_display, rh->egl_ctx);
     eglTerminate (rh->egl_display);
   } else {
-    if (rh->xsft->visual == DEFAULT_VISUAL)
-      free_pixmap (rh, rh->window);
+    free_pixmap (rh, rh->window);
     if (rh->native_window)
       ANativeWindow_release (rh->native_window);
   }
@@ -1375,6 +1577,12 @@ jwxyz_scale (Window main_window)
   return 2;
 }
 
+float
+jwxyz_font_scale (Window main_window)
+{
+  return jwxyz_scale (main_window);
+}
+
 
 const char *
 jwxyz_default_font_family (int require)
diff --git a/jwxyz/jwxyz-cocoa.h b/jwxyz/jwxyz-cocoa.h
index 5f2f61c..28f08b7 100644
--- a/jwxyz/jwxyz-cocoa.h
+++ b/jwxyz/jwxyz-cocoa.h
@@ -14,7 +14,7 @@
 
 #import "XScreenSaverView.h"
 
-#ifdef USE_IPHONE
+#ifdef HAVE_IPHONE
 # import <UIKit/UIKit.h>
 # define NSView           UIView
 # define NSOpenGLContext  EAGLContext
@@ -55,10 +55,10 @@ struct jwxyz_Drawable {
            get leaked if a Pixmap CFRetains this.
    */
   NSOpenGLContext *ogl_ctx;      // OpenGL rendering context (OS X)
-# ifdef USE_IPHONE
+# ifdef HAVE_IPHONE
   // TODO: Also on OS X as extensions.
   GLuint gl_framebuffer, gl_renderbuffer;
-# endif // USE_IPHONE
+# endif // HAVE_IPHONE
   CGImageRef cgi;
   XRectangle frame;
   union {
@@ -66,16 +66,16 @@ struct jwxyz_Drawable {
       XScreenSaverView *view;
       int last_mouse_x, last_mouse_y;
       struct jwxyz_Drawable *current_drawable;
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
       NSOpenGLPixelFormat *pixfmt;
       GLint virtual_screen;
-# else // USE_IPHONE
+# else // HAVE_IPHONE
       NSOpenGLContext *ogl_ctx_pixmap;
 # endif
     } window;
     struct {
       int depth;
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
       NSOpenGLPixelBuffer *gl_pbuffer;
       // GLuint blit_texture; // TODO: For blitting from Pbuffers
 # endif
@@ -87,11 +87,11 @@ struct jwxyz_Drawable {
 
 extern NSString *nsstring_from(const char *str, size_t len, int utf8_p);
 
-#ifdef USE_IPHONE
+#ifdef HAVE_IPHONE
 extern void create_framebuffer (GLuint *gl_framebuffer,
                                 GLuint *gl_renderbuffer);
 extern void check_framebuffer_status (void);
-#endif // USE_IPHONE
+#endif // HAVE_IPHONE
 
 #define jwxyz_window_view(w) ((w)->window.view)
 
diff --git a/jwxyz/jwxyz-cocoa.m b/jwxyz/jwxyz-cocoa.m
index 13666e7..f5bc551 100644
--- a/jwxyz/jwxyz-cocoa.m
+++ b/jwxyz/jwxyz-cocoa.m
@@ -1,4 +1,4 @@
-/* xscreensaver, Copyright (c) 1991-2019 Jamie Zawinski <jwz@jwz.org>
+/* xscreensaver, Copyright © 1991-2021 Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -11,11 +11,10 @@
 
 /* JWXYZ Is Not Xlib.
 
-   But it's a bunch of function definitions that bear some resemblance to
-   Xlib and that do Cocoa-ish or OpenGL-ish things that bear some resemblance
-   to the things that Xlib might have done.
+   Cocoa glue for macOS and iOS: fonts and such.
 
-   This code is used by both the original jwxyz.m and the new jwxyz-gl.c.
+   See the comment at the top of jwxyz-common.c for an explanation of
+   the division of labor between these various modules.
  */
 
 #import "jwxyzI.h"
@@ -24,7 +23,7 @@
 
 #include <stdarg.h>
 
-#ifdef USE_IPHONE
+#ifdef HAVE_IPHONE
 # import <OpenGLES/ES1/gl.h>
 # import <OpenGLES/ES1/glext.h>
 # define NSOpenGLContext EAGLContext
@@ -99,7 +98,7 @@ jwxyz_scale_1 (Window main_window, BOOL fonts_p)
 {
   float scale = 1;
 
-# ifdef USE_IPHONE
+# ifdef HAVE_IPHONE
   /* Since iOS screens are physically smaller than desktop screens, scale up
      the fonts to make them more readable.
 
@@ -112,12 +111,12 @@ jwxyz_scale_1 (Window main_window, BOOL fonts_p)
   if (scale < 1) // iPad Pro magnifies the backbuffer by 3x, which makes text
     scale = 1;   // excessively blurry in BSOD.
 
-# else  // !USE_IPHONE
+# else  // !HAVE_IPHONE
 
   /* Desktop retina displays also need fonts doubled. */
   scale = [main_window->window.view hackedContentScaleFactor:fonts_p];
 
-# endif // !USE_IPHONE
+# endif // !HAVE_IPHONE
 
   return scale;
 }
@@ -128,7 +127,7 @@ jwxyz_scale (Window main_window)
   return jwxyz_scale_1 (main_window, FALSE);
 }
 
-static float
+float
 jwxyz_font_scale (Window main_window)
 {
   return jwxyz_scale_1 (main_window, TRUE);
@@ -193,7 +192,7 @@ utf8_metrics (Display *dpy, NSFont *nsfont, NSString *nsstr, XCharStruct *cs)
     CGFloat advancement =
       CTRunGetTypographicBounds (run, r, &ascent, &descent, &leading);
 
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
     // Only necessary for when LCD smoothing is enabled, which iOS doesn't do.
     bbox.origin.x    -= 2.0/3.0;
     bbox.size.width  += 4.0/3.0;
@@ -234,7 +233,7 @@ utf8_metrics (Display *dpy, NSFont *nsfont, NSString *nsstr, XCharStruct *cs)
 static NSArray *
 font_family_members (NSString *family_name)
 {
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
   return [[NSFontManager sharedFontManager]
           availableMembersOfFontFamily:family_name];
 # else
@@ -275,7 +274,7 @@ try_font (NSFontTraitMask traits, NSFontTraitMask mask,
         traits & NSFixedPitchFontMask ? JWXYZ_STYLE_MONOSPACE : 0)]);
   }
 
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
   for (unsigned k = 0; k != family_members.count; ++k) {
 
     NSArray *member = [family_members objectAtIndex:k];
@@ -308,7 +307,7 @@ try_font (NSFontTraitMask traits, NSFontTraitMask mask,
       return f;
     }
   }
-# else // USE_IPHONE
+# else // HAVE_IPHONE
 
   // This trick needs iOS 3.1, see "Using SDK-Based Development".
   Class has_font_descriptor = [UIFontDescriptor class];
@@ -331,7 +330,7 @@ try_font (NSFontTraitMask traits, NSFontTraitMask mask,
         font_mask |= NSBoldFontMask;
       if (MATCH(@"Italic") || MATCH(@"Oblique"))
         font_mask |= NSItalicFontMask;
-      if (MATCH(@"Courier"))
+      if (MATCH(@"Courier") || MATCH(@"monospace") || MATCH(@"fixed"))
         font_mask |= NSFixedPitchFontMask;
     }
 
@@ -370,7 +369,7 @@ static NSFont *
 random_font (NSFontTraitMask traits, NSFontTraitMask mask, float size)
 {
 
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
   // Providing Unbold or Unitalic in the mask for availableFontNamesWithTraits
   // returns an empty list, at least on a system with default fonts only.
   NSArray *families = [[NSFontManager sharedFontManager]
@@ -395,7 +394,7 @@ random_font (NSFontTraitMask traits, NSFontTraitMask mask, float size)
 
     families = new_families;
   }
-# endif // USE_IPHONE
+# endif // HAVE_IPHONE
 
   long n = [families count];
   if (n <= 0) return 0;
@@ -563,7 +562,7 @@ jwxyz_render_text (Display *dpy, void *native_font,
 void
 jwxyz_get_pos (Window w, XPoint *xvpos, XPoint *xp)
 {
-# ifdef USE_IPHONE
+# ifdef HAVE_IPHONE
 
   xvpos->x = 0;
   xvpos->y = 0;
@@ -573,7 +572,7 @@ jwxyz_get_pos (Window w, XPoint *xvpos, XPoint *xp)
     xp->y = w->window.last_mouse_y;
   }
 
-# else  // !USE_IPHONE
+# else  // !HAVE_IPHONE
 
   NSWindow *nsw = [w->window.view window];
 
@@ -631,11 +630,11 @@ jwxyz_get_pos (Window w, XPoint *xvpos, XPoint *xp)
     xp->y = (int) p.y;
   }
 
-# endif // !USE_IPHONE
+# endif // !HAVE_IPHONE
 }
 
 
-#ifdef USE_IPHONE
+#ifdef HAVE_IPHONE
 
 void
 check_framebuffer_status (void)
@@ -693,7 +692,7 @@ create_framebuffer (GLuint *gl_framebuffer, GLuint *gl_renderbuffer)
   glBindRenderbufferOES (GL_RENDERBUFFER_OES, *gl_renderbuffer);
 }
 
-#endif // USE_IPHONE
+#endif // HAVE_IPHONE
 
 
 #if defined JWXYZ_QUARTZ
@@ -841,7 +840,7 @@ jwxyz_copy_area (Display *dpy, Drawable src, Drawable dst, GC gc,
   /* Strange and ugly flickering when going the glCopyTexImage2D route on
      OS X. (Early 2009 Mac mini, OS X 10.10)
    */
-# ifdef USE_IPHONE
+# ifdef HAVE_IPHONE
 
   /* TODO: This might not still work. */
   jwxyz_bind_drawable (dpy, dpy->main_window, src);
@@ -850,10 +849,10 @@ jwxyz_copy_area (Display *dpy, Drawable src, Drawable dst, GC gc,
   jwxyz_bind_drawable (dpy, dpy->main_window, dst);
   jwxyz_gl_copy_area_write_tex_image (dpy, gc, src_x, src_y,
                                       width, height, dst_x, dst_y);
-# else // !USE_IPHONE
+# else // !HAVE_IPHONE
   jwxyz_gl_copy_area_read_pixels (dpy, src, dst, gc,
                                   src_x, src_y, width, height, dst_x, dst_y);
-# endif // !USE_IPHONE
+# endif // !HAVE_IPHONE
   jwxyz_assert_gl ();
 }
 
@@ -877,7 +876,7 @@ jwxyz_assert_gl ()
 void
 jwxyz_assert_drawable (Window main_window, Drawable d)
 {
-#if !defined USE_IPHONE && !defined __OPTIMIZE__
+#if !defined HAVE_IPHONE && !defined __OPTIMIZE__
   XScreenSaverView *view = main_window->window.view;
   NSOpenGLContext *ogl_ctx = [view oglContext];
 
@@ -896,7 +895,7 @@ jwxyz_assert_drawable (Window main_window, Drawable d)
     perror([[exception reason] UTF8String]);
     jwxyz_abort();
   }
-#endif // !USE_IPHONE && !__OPTIMIZE__
+#endif // !HAVE_IPHONE && !__OPTIMIZE__
 }
 
 
@@ -925,7 +924,7 @@ jwxyz_bind_drawable (Window main_window, Drawable d)
   jwxyz_assert_gl ();
   jwxyz_assert_drawable (main_window, d);
 
-#if defined USE_IPHONE && !defined __OPTIMIZE__
+#if defined HAVE_IPHONE && !defined __OPTIMIZE__
   Drawable current_drawable = main_window->window.current_drawable;
   Assert (!current_drawable
             || current_drawable->ogl_ctx == [EAGLContext currentContext],
@@ -942,7 +941,7 @@ jwxyz_bind_drawable (Window main_window, Drawable d)
     main_window->window.current_drawable = d;
 
     /* Doing this repeatedly is probably not OK performance-wise. Probably. */
-#ifndef USE_IPHONE
+#ifndef HAVE_IPHONE
     [d->ogl_ctx makeCurrentContext];
 #else
     [EAGLContext setCurrentContext:d->ogl_ctx];
@@ -973,7 +972,7 @@ XCreatePixmap (Display *dpy, Drawable d,
   /* TODO: If Pixel buffers are not supported, do something about it. */
   Window w = XRootWindow (dpy, 0);
 
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
 
   p->ogl_ctx = [[NSOpenGLContext alloc]
                 initWithFormat:w->window.pixfmt
@@ -997,7 +996,7 @@ XCreatePixmap (Display *dpy, Drawable d,
                  mipMapLevel:0
         currentVirtualScreen:w->window.virtual_screen];
 
-# else // USE_IPHONE
+# else // HAVE_IPHONE
 
   p->ogl_ctx = w->window.ogl_ctx_pixmap;
 
@@ -1012,7 +1011,7 @@ XCreatePixmap (Display *dpy, Drawable d,
 
   glBindFramebufferOES(GL_FRAMEBUFFER_OES, p->gl_framebuffer);
 
-# endif // USE_IPHONE
+# endif // HAVE_IPHONE
 
   w->window.current_drawable = p;
   glViewport (0, 0, width, height);
@@ -1033,16 +1032,16 @@ XFreePixmap (Display *d, Pixmap p)
 
   Window w = RootWindow (d, 0);
 
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
   CFRelease (p->ogl_ctx);
   [p->ogl_ctx release];
 
   CFRelease (p->pixmap.gl_pbuffer);
   [p->pixmap.gl_pbuffer release];
-# else  // USE_IPHONE
+# else  // HAVE_IPHONE
   glDeleteRenderbuffersOES (1, &p->gl_renderbuffer);
   glDeleteFramebuffersOES (1, &p->gl_framebuffer);
-# endif // USE_IPHONE
+# endif // HAVE_IPHONE
 
   if (w->window.current_drawable == p) {
     w->window.current_drawable = NULL;
diff --git a/jwxyz/jwxyz-common.c b/jwxyz/jwxyz-common.c
index febb3b5..0b170f6 100644
--- a/jwxyz/jwxyz-common.c
+++ b/jwxyz/jwxyz-common.c
@@ -1,4 +1,4 @@
-/* xscreensaver, Copyright (c) 1991-2019 Jamie Zawinski <jwz@jwz.org>
+/* xscreensaver, Copyright (c) 1991-2020 Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -11,14 +11,48 @@
 
 /* JWXYZ Is Not Xlib.
 
-   But it's a bunch of function definitions that bear some resemblance to
-   Xlib and that do Cocoa-ish or OpenGL-ish things that bear some resemblance
-   to the things that Xlib might have done.
+   macOS and iOS:
+
+       jwxyz.m         -- Xlib in terms of Quartz / Core Graphics rendering,
+                          Renders into a CGContextRef that points to a CGImage
+                          in CPU RAM.
+       jwxyz-cocoa.m   -- Cocoa glue: fonts and such.
+
+   Android:
+
+       jwxyz-android.c -- Java / JNI glue.  Renders into an FBO texture if
+                          possible, otherwise an EGL PBuffer.
+
+       jwxyz-image.c   -- Pixmaps implemented in CPU RAM, for OpenGL hacks.
+                          Renders into an XImage, basically.
+
+       jwxyz-gl.c      -- Pixmaps implemented in terms of OpenGL textures,
+                          for X11 hacks (except kumppa, petri and slip).
+
+   Shared code:
+
+       jwxyz-common.c  -- Most of the Xlib implementation, used by all 3 OSes.
+       jwzgles.c       -- OpenGL 1.3 implemented in terms of OpenGLES 1.1.
+
+
+   Why two implemementations of Pixmaps for Android?
+
+     - GL hacks don't tend to need much in the way of Xlib, and having a
+       GL context to render Xlib alongside a GL context for rendering GL
+       seemed like trouble.
+
+     - X11 hacks render to a GL context because hardware acceleration tends
+       to work well with Xlib geometric stuff.  Better framerates, lower
+       power.
+
+   Why not eliminate jwxyz-cocoa.m and use jwxyz-gl.c on macOS and iOS
+   as well?
+
+     - Yeah, maybe.
 
-   This is the version of jwxyz for Android.  The version used by MacOS
-   and iOS is in jwxyz.m.
  */
 
+
 #ifdef HAVE_CONFIG_H
 # include "config.h"
 #endif
@@ -1134,7 +1168,7 @@ try_xlfd_font (Display *dpy, const char *name, Font fid)
     // This used to substitute Georgia for Times. Now it doesn't.
     if (CMP ("random")) {
       rand = True;
-    } else if (CMP ("fixed")) {
+    } else if (CMP ("fixed") || CMP ("monospace")) {
       require |= JWXYZ_STYLE_MONOSPACE;
       family_name = "Courier";
       family_name_size = strlen(family_name);
diff --git a/jwxyz/jwxyz-gl.c b/jwxyz/jwxyz-gl.c
index f1c13da..ed4c9c9 100644
--- a/jwxyz/jwxyz-gl.c
+++ b/jwxyz/jwxyz-gl.c
@@ -1,4 +1,4 @@
-/* xscreensaver, Copyright (c) 1991-2018 Jamie Zawinski <jwz@jwz.org>
+/* xscreensaver, Copyright (c) 1991-2020 Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -11,14 +11,14 @@
 
 /* JWXYZ Is Not Xlib.
 
-   But it's a bunch of function definitions that bear some resemblance to
-   Xlib and that do OpenGL-ish things that bear some resemblance to the
-   things that Xlib might have done.
+   Pixmaps implemented in terms of OpenGL textures, for Android X11 hacks.
+   Maybe this can someday be used on macOS and iOS as well.
 
-   This is the version of jwxyz for Android.  The version used by macOS
-   and iOS is in jwxyz.m.
+   See the comment at the top of jwxyz-common.c for an explanation of
+   the division of labor between these various modules.
  */
 
+
 /* Be advised, this is all very much a work in progress. */
 
 /* There is probably no reason to ever implement indexed-color rendering here,
@@ -77,7 +77,7 @@
 #include <wchar.h>
 
 #ifdef HAVE_COCOA
-# ifdef USE_IPHONE
+# ifdef HAVE_IPHONE
 #  import <QuartzCore/QuartzCore.h>
 #  include <OpenGLES/ES1/gl.h>
 #  include <OpenGLES/ES1/glext.h>
@@ -91,6 +91,9 @@
 # else
 #  include <GLES/gl.h>
 #  include <GLES/glext.h>
+#  ifdef HAVE_GLES3
+#   include <GLES3/gl3.h>
+#  endif
 # endif
 #endif
 
@@ -186,7 +189,7 @@ jwxyz_set_matrices (Display *dpy, unsigned width, unsigned height,
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   
-# if defined(USE_IPHONE) || defined(HAVE_ANDROID)
+# if defined(HAVE_IPHONE) || defined(HAVE_ANDROID)
 
   if (window_p && ignore_rotation_p(dpy)) {
     int o = (int) current_device_rotation();
@@ -917,7 +920,7 @@ jwxyz_gl_copy_area_read_tex_image (Display *dpy, unsigned src_height,
                                    unsigned int width, unsigned int height,
                                    int dst_x, int dst_y)
 {
-#  if defined HAVE_COCOA && !defined USE_IPHONE
+#  if defined HAVE_COCOA && !defined HAVE_IPHONE
   /* TODO: Does this help? */
   /* glFinish(); */
 #  endif
diff --git a/jwxyz/jwxyz-image.c b/jwxyz/jwxyz-image.c
index b1b3332..dc644ee 100644
--- a/jwxyz/jwxyz-image.c
+++ b/jwxyz/jwxyz-image.c
@@ -1,4 +1,4 @@
-/* xscreensaver, Copyright (c) 1991-2018 Jamie Zawinski <jwz@jwz.org>
+/* xscreensaver, Copyright (c) 1991-2020 Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -11,11 +11,11 @@
 
 /* JWXYZ Is Not Xlib.
 
-   But it's a bunch of function definitions that bear some resemblance to
-   Xlib and that do things to an XImage that bear some resemblance to the
-   things that Xlib might have done.
+   Pixmaps implemented in CPU RAM, for Android OpenGL hacks.
+   Renders into an XImage, basically.
 
-   This handles things when jwxyz-gl.c can't.
+   See the comment at the top of jwxyz-common.c for an explanation of
+   the division of labor between these various modules.
  */
 
 #ifdef HAVE_CONFIG_H
diff --git a/jwxyz/jwxyz.h b/jwxyz/jwxyz.h
index fa76571..3eac567 100644
--- a/jwxyz/jwxyz.h
+++ b/jwxyz/jwxyz.h
@@ -73,6 +73,8 @@ typedef struct jwxyz_XCharStruct	XCharStruct;
 typedef struct jwxyz_XComposeStatus	XComposeStatus;
 typedef struct jwxyz_XPixmapFormatValues XPixmapFormatValues;
 typedef struct jwxyz_XChar2b            XChar2b;
+typedef struct jwxyz_XRegion *		Region;
+typedef struct jwxyz_Box		Box;
 
 typedef union  jwxyz_XEvent		XEvent;
 typedef struct jwxyz_XAnyEvent		XAnyEvent;
@@ -286,6 +288,11 @@ typedef struct jwxyz_linked_point	linked_point;
 // #define GXnand		0xe		/* NOT src OR NOT dst */
 #define GXset			0xf		/* 1 */
 
+#define Unsorted		0
+#define YSorted			1
+#define YXSorted		2
+#define YXBanded		3
+
 #define XA_FONT                 18
 
 #define DefaultScreen(dpy) (0)
@@ -827,6 +834,17 @@ struct jwxyz_XChar2b {
   unsigned char byte2;
 };
 
+/* Xregion.h */
+struct jwxyz_Box {
+  short x1, x2, y1, y2;
+};
+
+struct jwxyz_XRegion {
+  long size;
+  long numRects;
+  Box *rects;
+  Box extents;
+};
 
 struct jwxyz_vtbl {
   Window (*root) (Display *);
diff --git a/jwxyz/jwxyz.m b/jwxyz/jwxyz.m
index c6a7af5..d25d580 100644
--- a/jwxyz/jwxyz.m
+++ b/jwxyz/jwxyz.m
@@ -1,4 +1,4 @@
-/* xscreensaver, Copyright (c) 1991-2019 Jamie Zawinski <jwz@jwz.org>
+/* xscreensaver, Copyright (c) 1991-2020 Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -11,13 +11,11 @@
 
 /* JWXYZ Is Not Xlib.
 
-   But it's a bunch of function definitions that bear some resemblance to
-   Xlib and that do Cocoa-ish things that bear some resemblance to the
-   things that Xlib might have done.
+   This file implements Xlib in terms of Quartz / Core Graphics rendering
+   for macOS and iOS.
 
-   This is the original version of jwxyz for MacOS and iOS.
-   The version used by Android is in jwxyz-gl.c and jwxyz-common.c.
-   Both versions depend on jwxyz-cocoa.m.
+   See the comment at the top of jwxyz-common.c for an explanation of
+   the division of labor between these various modules.
  */
 
 #ifdef JWXYZ_QUARTZ // entire file
@@ -26,7 +24,7 @@
 #import <stdint.h>
 #import <wchar.h>
 
-#ifdef USE_IPHONE
+#ifdef HAVE_IPHONE
 # import <UIKit/UIKit.h>
 # import <UIKit/UIScreen.h>
 # import <QuartzCore/QuartzCore.h>
@@ -66,7 +64,7 @@ struct jwxyz_Display {
   Visual visual;
   struct jwxyz_sources_data *timers_data;
 
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
   CGDirectDisplayID cgdpy;  /* ...of the one and only Window, main_window.
                                This can change if the window is dragged to
                                a different screen. */
@@ -399,7 +397,7 @@ jwxyz_window_resized (Display *dpy)
 {
   Window w = dpy->main_window;
 
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
   // Figure out which screen the window is currently on.
   {
     int wx, wy;
@@ -417,7 +415,7 @@ jwxyz_window_resized (Display *dpy)
     }
     Assert (dpy->cgdpy, "unable to find CGDisplay");
   }
-# endif // USE_IPHONE
+# endif // HAVE_IPHONE
 
 /*
   {
@@ -1394,9 +1392,9 @@ jwxyz_draw_NSImage_or_CGImage (Display *dpy, Drawable d,
                                XRectangle *geom_ret, int exif_rotation)
 {
   CGImageRef cgi;
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
   CGImageSourceRef cgsrc;
-# endif // USE_IPHONE
+# endif // HAVE_IPHONE
   NSSize imgr;
 
   CGContextRef cgc = d->cgc;
@@ -1406,7 +1404,7 @@ jwxyz_draw_NSImage_or_CGImage (Display *dpy, Drawable d,
     NSImage *nsimg = (NSImage *) img_arg;
     imgr = [nsimg size];
 
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
     // convert the NSImage to a CGImage via the toll-free-bridging 
     // of NSData and CFData...
     //
@@ -1416,9 +1414,9 @@ jwxyz_draw_NSImage_or_CGImage (Display *dpy, Drawable d,
     CFDataRef cfdata = (CFDataRef) nsdata;
     cgsrc = CGImageSourceCreateWithData (cfdata, NULL);
     cgi = CGImageSourceCreateImageAtIndex (cgsrc, 0, NULL);
-# else  // USE_IPHONE
+# else  // HAVE_IPHONE
     cgi = nsimg.CGImage;
-# endif // USE_IPHONE
+# endif // HAVE_IPHONE
 
   } else {
     cgi = (CGImageRef) img_arg;
@@ -1481,12 +1479,12 @@ jwxyz_draw_NSImage_or_CGImage (Display *dpy, Drawable d,
   CGContextDrawImage (cgc, dst2, cgi);
   CGContextRestoreGState (cgc);
 
-# ifndef USE_IPHONE
+# ifndef HAVE_IPHONE
   if (nsimg_p) {
     CFRelease (cgsrc);
     CGImageRelease (cgi);
   }
-# endif // USE_IPHONE
+# endif // HAVE_IPHONE
 
   if (geom_ret) {
     geom_ret->x = dst.origin.x;
@@ -1507,7 +1505,7 @@ jwxyz_png_to_ximage (Display *dpy, Visual *visual,
                                     [NSData dataWithBytes:png_data
                                             length:data_size]];
   if (! img) return 0;
-#ifndef USE_IPHONE
+#ifndef HAVE_IPHONE
   NSBitmapImageRep *bm = [NSBitmapImageRep
                            imageRepWithData:
                              [NSBitmapImageRep
@@ -1525,7 +1523,7 @@ jwxyz_png_to_ximage (Display *dpy, Visual *visual,
   convert_mode_t mode = (([bm bitmapFormat] & NSAlphaFirstBitmapFormat)
                          ? CONVERT_MODE_ROTATE_MASK
                          : 0);
-#else  // USE_IPHONE
+#else  // HAVE_IPHONE
   CGImageRef cgi = [img CGImage];
   if (!cgi) {
     [img release];
@@ -1547,7 +1545,7 @@ jwxyz_png_to_ximage (Display *dpy, Visual *visual,
 
   convert_mode_t mode = convert_mode_to_rgba (bitmap_info);
 
-#endif // USE_IPHONE
+#endif // HAVE_IPHONE
 
   XImage *image = XCreateImage (dpy, visual, 32, ZPixmap, 0, 0,
                                 width, height, 8, 0);
@@ -1567,7 +1565,7 @@ jwxyz_png_to_ximage (Display *dpy, Visual *visual,
 
   [img release];
 
-#ifndef USE_IPHONE
+#ifndef HAVE_IPHONE
   // [bm release];
 # else
   CGContextRelease (cgc);
diff --git a/jwxyz/jwxyzI.h b/jwxyz/jwxyzI.h
index f7560f7..6ff5d38 100644
--- a/jwxyz/jwxyzI.h
+++ b/jwxyz/jwxyzI.h
@@ -1,4 +1,4 @@
-/* xscreensaver, Copyright (c) 1991-2018 Jamie Zawinski <jwz@jwz.org>
+/* xscreensaver, Copyright © 1991-2021 Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -52,6 +52,7 @@ extern unsigned int jwxyz_drawable_depth (Drawable d);
    meaning of -[UIView contentScaleFactor] on iOS.
  */
 extern float jwxyz_scale (Window main_window);
+extern float jwxyz_font_scale (Window main_window);
 
 extern const char *jwxyz_default_font_family (int require);
 extern void *jwxyz_load_native_font (Window main_window,
@@ -130,7 +131,7 @@ extern void jwxyz_quartz_copy_area (Display *dpy, Drawable src, Drawable dst,
 
 # ifdef JWXYZ_GL
 
-#  if defined(USE_IPHONE)
+#  if defined(HAVE_IPHONE)
 #   include <OpenGLES/ES1/gl.h>
 #  elif defined(HAVE_COCOA)
 #   include <OpenGL/gl.h>
diff --git a/jwxyz/jwzgles.c b/jwxyz/jwzgles.c
index b26bc3a..26f1188 100644
--- a/jwxyz/jwzgles.c
+++ b/jwxyz/jwzgles.c
@@ -1,4 +1,4 @@
-/* xscreensaver, Copyright (c) 2012-2019 Jamie Zawinski <jwz@jwz.org>
+/* xscreensaver, Copyright © 2012-2021 Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -9,9 +9,14 @@
  * implied warranty.
  */
 
-/* A compatibility shim to allow OpenGL 1.3 source code to work in an
-   OpenGLES environment, where almost every OpenGL 1.3 function has
-   been "deprecated".
+/* JWXYZ Is Not Xlib.
+
+   See the comment at the top of jwxyz-common.c for an explanation of
+   the division of labor between these various modules.
+
+   This file is a compatibility shim to allow OpenGL 1.3 source code to
+   work in an OpenGLES environment, where almost every OpenGL 1.3 function
+   has been "deprecated".
 
    There are two major operations going on here:
 
@@ -97,9 +102,17 @@
    OpenGLES 1.0	 2003 (deprecated 80% of the language; fork of OpenGL 1.3)
    OpenGL   1.5	 2003 (added VBOs)
    OpenGLES 1.1	 2004 (fork of OpenGL 1.5)
-   OpenGL   2.0	 2004 (a political quagmire)
-   OpenGLES 2.0	 2007 (deprecated 95% of the language; fork of OpenGL 2.0)
+   OpenGL   2.0	 2004 (a political quagmire, added shader language GLSL 1.1)
+   OpenGLES 2.0	 2007 (deprecated 95% of the language; fork of OpenGL 2.0;
+                       GLSL 1.20)
    OpenGL   3.0	 2008 (added FBOs, VAOs, deprecated 60% of the language)
+   OpenGL   3.3  2010 (OpenGL 3.3 and OpenGL 4.0 released concurrently;
+                       3.3 has GLSL 3.30, but 4.0 has GLSL 4.00)
+   OpenGLES 3.0	 2012 (same as WebGL 2.0, but has GLSL 3.00)
+   OpenGL   4.3	 2012 (superset of GLES 3.0, but has GLSL 4.30)
+
+   It's like these assholes are going out of their way to make it all just
+   as incoherent and difficult to understand as possible.
 
 
    Some things that are missing:
@@ -152,6 +165,10 @@
 
 #ifdef HAVE_JWZGLES	/* whole file */
 
+#ifndef HAVE_GL
+# error HAVE_GL is undefined
+#endif
+
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
@@ -162,21 +179,30 @@
 # include <unistd.h>
 #endif /* HAVE_UNISTD_H */
 
-#if defined(USE_IPHONE)
-# include <OpenGLES/ES1/gl.h>
-# include <OpenGLES/ES1/glext.h>
+#if defined(HAVE_IPHONE)
+# ifdef HAVE_GLES3
+#  include <OpenGLES/ES3/gl.h>
+#  include <OpenGLES/ES3/glext.h>
+# else  /* !HAVE_GLES3 */
+#  include <OpenGLES/ES1/gl.h>
+#  include <OpenGLES/ES1/glext.h>
+# endif /* !HAVE_GLES3 */
 #elif defined(HAVE_COCOA)
 # include <OpenGL/gl.h>
-# include <OpenGL/glu.h>
 #elif defined(HAVE_ANDROID)
 # include <GLES/gl.h>
+# ifdef HAVE_GLES3
+#  include <GLES3/gl3.h>
+# endif
 # include <android/log.h>
 #else /* real X11 */
 # ifndef  GL_GLEXT_PROTOTYPES
 #  define GL_GLEXT_PROTOTYPES /* for glBindBuffer */
 # endif
-# include <GL/glx.h>
-# include <GL/glu.h>
+# include <GLES/gl.h>
+# ifdef HAVE_GLES3
+# include <GLES3/gl3.h>
+# endif /* HAVE_GLES3 */
 #endif
 
 #include "jwzglesI.h"
@@ -1759,8 +1785,9 @@ jwzgles_glDrawBuffer (GLenum buf)
     }
   else
     {
-/*      Assert (buf == GL_BACK, "glDrawBuffer: back buffer only"); */
-# ifndef GL_VERSION_ES_CM_1_0  /* not compiling against OpenGLES 1.x */
+      Assert (buf == GL_BACK, "glDrawBuffer: back buffer only");
+# if !defined(GL_VERSION_ES_CM_1_0)
+      /* not compiling against OpenGLES 1.x */
       if (! state->replaying_list)
         LOG1 ("direct %-12s", "glDrawBuffer");
       glDrawBuffer (buf);      /* the real one */
@@ -1770,6 +1797,29 @@ jwzgles_glDrawBuffer (GLenum buf)
 }
 
 
+void jwzgles_glDrawElements (GLenum mode, GLsizei count, GLenum type,
+                             const GLvoid *indices)
+{
+  Assert (!state->compiling_verts, "not allowed inside glBegin");
+  Assert (!state->compiling_list,  "not allowed inside glNewList");
+# if 0
+  if (state->compiling_list)
+    {
+      void_int vv[1];
+      vv[0].i = buf;
+      /* #### This won't work because indices is a pointer */
+      list_push ("glDrawElements", (list_fn_cb) &jwzgles_glDrawElements, 
+                 PROTO_IIII, vv);
+    }
+  else
+# endif /* 0 */
+    {
+      glDrawElements (mode, count, type, indices);      /* the real one */
+      CHECK("glDrawElements");
+    }
+}
+
+
 /* Given an array of sets of 4 elements of arbitrary size, convert it
    to an array of sets of 6 elements instead: ABCD becomes ABC BCD.
  */
@@ -1966,15 +2016,15 @@ jwzgles_glEnd (void)
   jwzgles_glDrawArrays (s->mode, 0, s->count);
   glBindBuffer (GL_ARRAY_BUFFER, 0);    /* Keep out of others' hands */
 
-# define RESET(VAR,FN,ARG) do { \
+# define RESET(VAR,ENFN,DISFN,ARG) do { \
          if (is_##VAR != was_##VAR) { \
-            if (was_##VAR) jwzgles_glEnable##FN (ARG); \
-            else jwzgles_glDisable##FN (ARG); \
+            if (was_##VAR) jwzgles_gl##ENFN (ARG); \
+            else jwzgles_gl##DISFN (ARG); \
          }} while(0)
-  RESET (norm,  ClientState, GL_NORMAL_ARRAY);
-  RESET (tex,   ClientState, GL_TEXTURE_COORD_ARRAY);
-  RESET (color, ClientState, GL_COLOR_ARRAY);
-  RESET (mat,   ,            GL_COLOR_MATERIAL);
+  RESET (norm,  EnableClientState, DisableClientState, GL_NORMAL_ARRAY);
+  RESET (tex,   EnableClientState, DisableClientState, GL_TEXTURE_COORD_ARRAY);
+  RESET (color, EnableClientState, DisableClientState, GL_COLOR_ARRAY);
+  RESET (mat,   Enable,            Disable,            GL_COLOR_MATERIAL);
 # undef RESET
 
   s->count  = 0;
@@ -2987,7 +3037,12 @@ jwzgles_glTexImage1D (GLenum target, GLint level,
   Assert (!state->compiling_verts, "glTexImage1D not allowed inside glBegin");
   /* technically legal, but stupid! */
   Assert (!state->compiling_list, "glTexImage1D inside glNewList");
+# ifndef HAVE_GLSL
+  /* If the underlying library is GLES2, then textures can be any size.
+     Portable code should still be using pow2 sizes, unless it's in a branch
+     that is guaranteed not to run in a GLES1 or OpenGL 1.3 context. */
   Assert (width  == to_pow2(width), "width must be a power of 2");
+# endif
 
   if (target == GL_TEXTURE_1D) target = GL_TEXTURE_2D;
   jwzgles_glTexImage2D (target, level, internalFormat, width, 1,
@@ -3010,8 +3065,13 @@ jwzgles_glTexImage2D (GLenum target,
   Assert (!state->compiling_list,  /* technically legal, but stupid! */
           "glTexImage2D not allowed inside glNewList");
 
+# ifndef HAVE_GLSL
+  /* If the underlying library is GLES2, then textures can be any size.
+     Portable code should still be using pow2 sizes, unless it's in a branch
+     that is guaranteed not to run in a GLES1 or OpenGL 1.3 context. */
   Assert (width  == to_pow2(width),   "width must be a power of 2");
   Assert (height == to_pow2(height), "height must be a power of 2");
+# endif
 
   /* OpenGLES no longer supports "4" as a synonym for "RGBA". */
   switch (internalFormat) {
@@ -4131,12 +4191,13 @@ jwzgles_gluCheckExtension (const GLubyte *ext_name, const GLubyte *ext_string)
   size_t ext_len = strlen ((const char *)ext_name);
 
   for (;;) {
+    char last_ch;
     const GLubyte *found = (const GLubyte *)strstr ((const char *)ext_string,
                                                     (const char *)ext_name);
     if (!found)
       break;
 
-    char last_ch = found[ext_len];
+    last_ch = found[ext_len];
     if ((found == ext_string || found[-1] == ' ') &&
         (last_ch == ' ' || !last_ch)) {
       return GL_TRUE;
@@ -4288,7 +4349,7 @@ void jwzgles_##NAME (ARGS_##SIG)					\
 WRAP (glActiveTexture,	I)
 WRAP (glAlphaFunc,	IF)
 WRAP (glBlendFunc,	II)
-//WRAP (glBlendColor,     FFFF);
+/*WRAP (glBlendColor,     FFFF);*/
 WRAP (glClear,		I)
 WRAP (glClearColor,	FFFF)
 WRAP (glClearStencil,	I)
@@ -4329,5 +4390,4 @@ WRAP (glTranslatef,	FFF)
 #define TYPE_IV GLuint
 WRAP (glDeleteTextures,	IIV)
 
-
 #endif /* HAVE_JWZGLES - whole file */
diff --git a/jwxyz/jwzgles.h b/jwxyz/jwzgles.h
index 9c8d1e2..10c5bd8 100644
--- a/jwxyz/jwzgles.h
+++ b/jwxyz/jwzgles.h
@@ -21,7 +21,6 @@
 # error: do not include this without HAVE_JWZGLES
 #endif
 
-
 #include "jwzglesI.h"
 
 
@@ -269,7 +268,6 @@
 #define glRasterPos4iv			jwzgles_glRasterPos4iv
 #define glRasterPos4s			jwzgles_glRasterPos4s
 #define glRasterPos4sv			jwzgles_glRasterPos4sv
-#define glReadBuffer			jwzgles_glReadBuffer
 #define glRectd				jwzgles_glRectf
 #define glRectdv			jwzgles_glRectdv
 #define glRectf				jwzgles_glRectf
diff --git a/jwxyz/jwzglesI.h b/jwxyz/jwzglesI.h
index b90bad4..975b3ee 100644
--- a/jwxyz/jwzglesI.h
+++ b/jwxyz/jwzglesI.h
@@ -1,4 +1,4 @@
-/* xscreensaver, Copyright (c) 2012-2019 Jamie Zawinski <jwz@jwz.org>
+/* xscreensaver, Copyright © 2012-2021 Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -184,6 +184,7 @@ extern void jwzgles_glDepthFunc (GLuint);
 extern void jwzgles_glDepthMask (GLuint);
 extern void jwzgles_glDisable (GLuint);
 extern void jwzgles_glDrawArrays (GLuint, GLuint, GLuint);
+extern void jwzgles_glDrawElements (GLenum, GLsizei, GLenum, const GLvoid *);
 extern GLboolean jwzgles_glIsEnabled (GLuint);
 extern void jwzgles_glEnable (GLuint);
 extern void jwzgles_glFrontFace (GLuint);
@@ -206,7 +207,6 @@ extern void jwzgles_glViewport (GLuint, GLuint, GLuint, GLuint);
 extern void jwzgles_glTranslatef (GLfloat, GLfloat, GLfloat);
 extern void jwzgles_glRotatef (GLfloat, GLfloat, GLfloat, GLfloat);
 extern void jwzgles_glRotated (GLdouble, GLdouble x, GLdouble y, GLdouble z);
-extern void jwzgles_glReadBuffer (GLuint);
 extern void jwzgles_glScalef (GLfloat, GLfloat, GLfloat);
 extern void jwzgles_glColor3f (GLfloat, GLfloat, GLfloat);
 extern void jwzgles_glColor4f (GLfloat, GLfloat, GLfloat, GLfloat);