Added dynamic symbol loading for GLX functions, closes #41

Makefile

@@ -45,7 +45,7 @@ endif
 
 ifndef DISABLE_GLX
     CFLAGS_GLX = -DGLAVA_GLX
-    LDFLAGS_GLX = -lGLX -lXrender
+    LDFLAGS_GLX = -lXrender
 endif
 
 ifeq ($(INSTALL),osx)

README.md

@@ -27,7 +27,6 @@ You can pass `BUILD=debug` to the makefile for debug builds of both glad and gla
 - glad (included as a submodule)
 - python (required to generate bindings with glad)
 - GCC (this program uses GNU C features)
-- GLX headers (optional, disable direct GLX support with `DISABLE_GLX=1`), usually the development packages for `libgl` include this on your distro
 
 **Ubuntu/Debian users:** the following command ensures you have all the needed packages and headers to compile GLava:
 ```bash

glx_wcb.c

@@ -13,22 +13,154 @@
 #include <math.h>
 #include <time.h>
 
+#include <dlfcn.h>
+
 #include <X11/Xlib.h>
 #include <X11/extensions/Xrender.h>
 #include <X11/extensions/shape.h>
 #include <X11/Xatom.h>
 
 #include <glad/glad.h>
-#include <GL/glx.h>
 
 #include "render.h"
 #include "xwin.h"
 
+typedef struct __GLXcontextRec *GLXContext;
+typedef XID GLXPixmap;
+typedef XID GLXDrawable;
+
+typedef void (*__GLXextFuncPtr)(void);
+
+/* GLX 1.3 and later */
+typedef struct __GLXFBConfigRec *GLXFBConfig;
+typedef XID GLXFBConfigID;
+typedef XID GLXContextID;
+typedef XID GLXWindow;
+typedef XID GLXPbuffer;
+
+/*
+ * Tokens for glXChooseVisual and glXGetConfig:
+ */
+#define GLX_USE_GL		1
+#define GLX_BUFFER_SIZE		2
+#define GLX_LEVEL		3
+#define GLX_RGBA		4
+#define GLX_DOUBLEBUFFER	5
+#define GLX_STEREO		6
+#define GLX_AUX_BUFFERS		7
+#define GLX_RED_SIZE		8
+#define GLX_GREEN_SIZE		9
+#define GLX_BLUE_SIZE		10
+#define GLX_ALPHA_SIZE		11
+#define GLX_DEPTH_SIZE		12
+#define GLX_STENCIL_SIZE	13
+#define GLX_ACCUM_RED_SIZE	14
+#define GLX_ACCUM_GREEN_SIZE	15
+#define GLX_ACCUM_BLUE_SIZE	16
+#define GLX_ACCUM_ALPHA_SIZE	17
+
+
+/*
+ * Error codes returned by glXGetConfig:
+ */
+#define GLX_BAD_SCREEN		1
+#define GLX_BAD_ATTRIBUTE	2
+#define GLX_NO_EXTENSION	3
+#define GLX_BAD_VISUAL		4
+#define GLX_BAD_CONTEXT		5
+#define GLX_BAD_VALUE       	6
+#define GLX_BAD_ENUM		7
+
+/*
+ * GLX 1.1 and later:
+ */
+#define GLX_VENDOR		1
+#define GLX_VERSION		2
+#define GLX_EXTENSIONS 		3
+
+
+/*
+ * GLX 1.3 and later:
+ */
+#define GLX_CONFIG_CAVEAT		0x20
+#define GLX_DONT_CARE			0xFFFFFFFF
+#define GLX_X_VISUAL_TYPE		0x22
+#define GLX_TRANSPARENT_TYPE		0x23
+#define GLX_TRANSPARENT_INDEX_VALUE	0x24
+#define GLX_TRANSPARENT_RED_VALUE	0x25
+#define GLX_TRANSPARENT_GREEN_VALUE	0x26
+#define GLX_TRANSPARENT_BLUE_VALUE	0x27
+#define GLX_TRANSPARENT_ALPHA_VALUE	0x28
+#define GLX_WINDOW_BIT			0x00000001
+#define GLX_PIXMAP_BIT			0x00000002
+#define GLX_PBUFFER_BIT			0x00000004
+#define GLX_AUX_BUFFERS_BIT		0x00000010
+#define GLX_FRONT_LEFT_BUFFER_BIT	0x00000001
+#define GLX_FRONT_RIGHT_BUFFER_BIT	0x00000002
+#define GLX_BACK_LEFT_BUFFER_BIT	0x00000004
+#define GLX_BACK_RIGHT_BUFFER_BIT	0x00000008
+#define GLX_DEPTH_BUFFER_BIT		0x00000020
+#define GLX_STENCIL_BUFFER_BIT		0x00000040
+#define GLX_ACCUM_BUFFER_BIT		0x00000080
+#define GLX_NONE			0x8000
+#define GLX_SLOW_CONFIG			0x8001
+#define GLX_TRUE_COLOR			0x8002
+#define GLX_DIRECT_COLOR		0x8003
+#define GLX_PSEUDO_COLOR		0x8004
+#define GLX_STATIC_COLOR		0x8005
+#define GLX_GRAY_SCALE			0x8006
+#define GLX_STATIC_GRAY			0x8007
+#define GLX_TRANSPARENT_RGB		0x8008
+#define GLX_TRANSPARENT_INDEX		0x8009
+#define GLX_VISUAL_ID			0x800B
+#define GLX_SCREEN			0x800C
+#define GLX_NON_CONFORMANT_CONFIG	0x800D
+#define GLX_DRAWABLE_TYPE		0x8010
+#define GLX_RENDER_TYPE			0x8011
+#define GLX_X_RENDERABLE		0x8012
+#define GLX_FBCONFIG_ID			0x8013
+#define GLX_RGBA_TYPE			0x8014
+#define GLX_COLOR_INDEX_TYPE		0x8015
+#define GLX_MAX_PBUFFER_WIDTH		0x8016
+#define GLX_MAX_PBUFFER_HEIGHT		0x8017
+#define GLX_MAX_PBUFFER_PIXELS		0x8018
+#define GLX_PRESERVED_CONTENTS		0x801B
+#define GLX_LARGEST_PBUFFER		0x801C
+#define GLX_WIDTH			0x801D
+#define GLX_HEIGHT			0x801E
+#define GLX_EVENT_MASK			0x801F
+#define GLX_DAMAGED			0x8020
+#define GLX_SAVED			0x8021
+#define GLX_WINDOW			0x8022
+#define GLX_PBUFFER			0x8023
+#define GLX_PBUFFER_HEIGHT              0x8040
+#define GLX_PBUFFER_WIDTH               0x8041
+#define GLX_RGBA_BIT			0x00000001
+#define GLX_COLOR_INDEX_BIT		0x00000002
+#define GLX_PBUFFER_CLOBBER_MASK	0x08000000
+
+/*
+ * GLX 1.4 and later:
+ */
+#define GLX_SAMPLE_BUFFERS              0x186a0 /*100000*/
+#define GLX_SAMPLES                     0x186a1 /*100001*/
+
+/* glXCreateContextAttribsARB extension definitions */
+
 #define GLX_CONTEXT_MAJOR_VERSION_ARB       0x2091
 #define GLX_CONTEXT_MINOR_VERSION_ARB       0x2092
+
 typedef GLXContext (*glXCreateContextAttribsARBProc)(Display*, GLXFBConfig, GLXContext, Bool, const int*);
 typedef void       (*glXSwapIntervalEXTProc)        (Display*, GLXDrawable, int);
 
+GLXFBConfig*    (*glXChooseFBConfig)       (Display* dpy, int screen, const int* attribList, int* nitems);
+XVisualInfo*    (*glXGetVisualFromFBConfig)(Display* dpy, GLXFBConfig config);
+int             (*glXGetFBConfigAttrib)    (Display* dpy, GLXFBConfig config, int attribute, int *value );
+Bool            (*glXMakeCurrent)          (Display* dpy, GLXDrawable drawable, GLXContext ctx);
+GLXDrawable     (*glXGetCurrentDrawable)   (void);
+__GLXextFuncPtr (*glXGetProcAddressARB)    (const GLubyte *);
+void            (*glXSwapBuffers)          (Display* dpy, GLXDrawable drawable);
+
 extern struct gl_wcb wcb_glx;
 
 static Display* display;
@@ -55,6 +187,39 @@ static void init(void) {
     focused     = false;
     maximized   = false;
     transparent = false;
+
+    void* hgl  = dlopen("libGL.so", RTLD_LAZY);
+    void* hglx = dlopen("libGLX.so", RTLD_LAZY);
+
+    if (!hgl && !hglx) {
+        fprintf(stderr, "Failed to load GLX functions (libGL and libGLX do not exist!)\n");
+        exit(EXIT_FAILURE);
+    }
+
+    /* Depending on the graphics driver, the GLX functions that we need may either be in libGL or
+       libGLX. */
+    void* resolve_f(const char* symbol) {
+        void* s = NULL;
+        if (hgl)        s = dlsym(hgl,  symbol);
+        if (!s && hglx) s = dlsym(hglx, symbol);
+        if (!s) {
+            fprintf(stderr, "Failed to resolve GLX symbol: `%s`\n", symbol);
+            exit(EXIT_FAILURE);
+        }
+        return s;
+    }
+
+    #define resolve(name) do { name = (typeof(name)) resolve_f(#name); } while (0)
+
+    resolve(glXChooseFBConfig);
+    resolve(glXGetVisualFromFBConfig);
+    resolve(glXGetFBConfigAttrib);
+    resolve(glXMakeCurrent);
+    resolve(glXGetCurrentDrawable);
+    resolve(glXGetProcAddressARB);
+    resolve(glXSwapBuffers);
+    
+    #undef resolve
 }
 
 static void apply_decorations(Window w) {