Make window rgba and set background transparent to allow window clear to work with transparency

13 files changed, 104 insertions, 73 deletions

diff --git a/README.md b/README.md
index f959d7c..8bceb2c 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@ Written in C and uses OpenGL 2.0 to support as many platforms as possible.\
 Right now mgl only supports x11.
 # Dependencies
 ## Build
-`xlib`
+`x11, xrender`
 ## Runtime
 `libglvnd (libGL.so)`
 # Notes
diff --git a/include/mgl/gl.h b/include/mgl/gl.h
index 2546a68..cf2cd47 100644
--- a/include/mgl/gl.h
+++ b/include/mgl/gl.h
@@ -9,15 +9,17 @@ typedef struct _XVisualInfo _XVisualInfo;
 typedef struct _XDisplay Display;
 typedef struct __GLXcontextRec *GLXContext;
 typedef unsigned long GLXDrawable;
+typedef struct __GLXFBConfigRec *GLXFBConfig;
 
 typedef struct {
     void *handle;
 
-    _XVisualInfo* (*glXChooseVisual)(Display *dpy, int screen, int *attribList);
-    GLXContext (*glXCreateContext)(Display *dpy, _XVisualInfo *vis, GLXContext shareList, int direct);
+    GLXContext (*glXCreateNewContext)(Display *dpy, GLXFBConfig config, int renderType, GLXContext shareList, int direct);
+    int (*glXMakeContextCurrent)(Display *dpy, GLXDrawable draw, GLXDrawable read, GLXContext ctx);
     void (*glXDestroyContext)(Display *dpy, GLXContext ctx);
-    int (*glXMakeCurrent)(Display *dpy, GLXDrawable drawable, GLXContext ctx);
     void (*glXSwapBuffers)(Display *dpy, GLXDrawable drawable);
+    GLXFBConfig* (*glXChooseFBConfig)(Display *dpy, int screen, const int *attribList, int *nitems);
+    _XVisualInfo* (*glXGetVisualFromFBConfig)(Display *dpy, GLXFBConfig config);
 
     void (*glViewport)(int x, int y, int width, int height);
     void (*glScissor)(int x, int y, int width, int height);
diff --git a/include/mgl/gl_macro.h b/include/mgl/gl_macro.h
index 043d3f9..3141f78 100644
--- a/include/mgl/gl_macro.h
+++ b/include/mgl/gl_macro.h
@@ -1,23 +1,20 @@
 #ifndef MGL_GL_MACRO_H
 #define MGL_GL_MACRO_H
 
-#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
+
+#define GLX_DRAWABLE_TYPE 0x8010
+#define GLX_RENDER_TYPE 0x8011
+#define GLX_RGBA_BIT 0x00000001
+#define GLX_WINDOW_BIT 0x00000001
+#define GLX_RGBA_TYPE 0x8014
 
 #define GL_COLOR_BUFFER_BIT 0x00004000
 #define GL_BLEND 0x0BE2
diff --git a/include/mgl/mgl.h b/include/mgl/mgl.h
index 4cbc8d5..bd0ae5b 100644
--- a/include/mgl/mgl.h
+++ b/include/mgl/mgl.h
@@ -11,6 +11,7 @@ struct mgl_context {
     mgl_connection connection;
     mgl_gl gl;
     _XVisualInfo *visual_info;
+    GLXFBConfig fbconfig;
     unsigned long wm_delete_window_atom;
     unsigned long net_wm_ping_atom;
     unsigned long net_wm_pid_atom;
diff --git a/project.conf b/project.conf
index 8b939d6..b22578c 100644
--- a/project.conf
+++ b/project.conf
@@ -8,4 +8,5 @@ platforms = ["posix"]
 expose_include_dirs = ["include"]
 
 [dependencies]
-x11 = "1"
\ No newline at end of file
+x11 = ">=0.5"
+xrender = ">=0.5"
\ No newline at end of file
diff --git a/src/gl.c b/src/gl.c
index 0745810..ead18dc 100644
--- a/src/gl.c
+++ b/src/gl.c
@@ -8,13 +8,13 @@ typedef struct {
     const char *name;
 } dlsym_assign;
 
-static void* dlsym_print_fail(void *handle, const char *name) {
+static void* dlsym_print_fail(void *handle, const char *name, int required) {
     dlerror();
     void *sym = dlsym(handle, name);
     char *err_str = dlerror();
 
     if(!sym)
-        fprintf(stderr, "dlsym(handle, \"%s\") failed, error: %s\n", name, err_str ? err_str : "(null)");
+        fprintf(stderr, "mgl %s: dlsym(handle, \"%s\") failed, error: %s\n", required ? "error" : "warning", name, err_str ? err_str : "(null)");
 
     return sym;
 }
@@ -26,16 +26,17 @@ int mgl_gl_load(mgl_gl *self) {
     const char *glx_path = "libGL.so.1";
     self->handle = dlopen(glx_path, RTLD_LAZY);
     if(!self->handle) {
-        fprintf(stderr, "dlopen(\"%s\", RTLD_LAZY) failed\n", glx_path);
+        fprintf(stderr, "mgl error:dlopen(\"%s\", RTLD_LAZY) failed\n", glx_path);
         return -1;
     }
 
     const dlsym_assign required_dlsym[] = {
-        { &self->glXChooseVisual, "glXChooseVisual" },
-        { &self->glXCreateContext, "glXCreateContext" },
+        { &self->glXCreateNewContext, "glXCreateNewContext" },
+        { &self->glXMakeContextCurrent, "glXMakeContextCurrent" },
         { &self->glXDestroyContext, "glXDestroyContext" },
-        { &self->glXMakeCurrent, "glXMakeCurrent" },
         { &self->glXSwapBuffers, "glXSwapBuffers" },
+        { &self->glXChooseFBConfig, "glXChooseFBConfig" },
+        { &self->glXGetVisualFromFBConfig, "glXGetVisualFromFBConfig" },
 
         { &self->glViewport, "glViewport" },
         { &self->glScissor, "glScissor" },
@@ -98,7 +99,7 @@ int mgl_gl_load(mgl_gl *self) {
     };
 
     for(int i = 0; required_dlsym[i].func; ++i) {
-        *required_dlsym[i].func = dlsym_print_fail(self->handle, required_dlsym[i].name);
+        *required_dlsym[i].func = dlsym_print_fail(self->handle, required_dlsym[i].name, 1);
         if(!required_dlsym[i].func) {
             mgl_gl_unload(self);
             return -1;
@@ -114,7 +115,7 @@ int mgl_gl_load(mgl_gl *self) {
     };
 
     for(int i = 0; optional_dlsym[i].func; ++i) {
-        *optional_dlsym[i].func = dlsym_print_fail(self->handle, optional_dlsym[i].name);
+        *optional_dlsym[i].func = dlsym_print_fail(self->handle, optional_dlsym[i].name, 0);
     }
 
     return 0;
diff --git a/src/graphics/font.c b/src/graphics/font.c
index 9a99f22..4fd9840 100644
--- a/src/graphics/font.c
+++ b/src/graphics/font.c
@@ -39,13 +39,13 @@ int mgl_font_load_from_file(mgl_font *self, const mgl_memory_mapped_file *mapped
 
     self->font_info = malloc(sizeof(stbtt_fontinfo));
     if(!self->font_info) {
-        fprintf(stderr, "Error: failed to load font, error: out of memory\n");
+        fprintf(stderr, "mgl error: failed to load font, error: out of memory\n");
         return -1;
     }
 
     /* TODO: Handle font offset with ttc */
     if(!stbtt_InitFont(self->font_info, mapped_file->data, stbtt_GetFontOffsetForIndex(mapped_file->data, 0))) {
-        fprintf(stderr, "Error: failed to load font, error: stbtt_InitFont failed\n");
+        fprintf(stderr, "mgl error: failed to load font, error: stbtt_InitFont failed\n");
         mgl_font_unload(self);
         return -1;
     }
@@ -137,7 +137,7 @@ static void mgl_font_handle_new_render_position(mgl_font *self, int glyph_width)
                     mgl_font_char_iterator_next(&font_char_it);
                 }
             } else {
-                fprintf(stderr, "Error: failed to resize font atlas\n");
+                fprintf(stderr, "mgl error: failed to resize font atlas\n");
             }
         } else if(self->font_atlas.render_section == MGL_ATLAS_SECTION_RIGHT && self->font_atlas.pointer_position.y + self->current_line_max_height + (int)self->character_size + GLYPH_PADDING >= self->font_atlas.prev_height) {
             self->font_atlas.right_section_height = self->font_atlas.pointer_position.y + self->current_line_max_height;
@@ -174,7 +174,7 @@ int mgl_font_get_glyph(mgl_font *self, uint32_t codepoint, mgl_font_glyph *glyph
         if(mgl_texture_load_from_memory(&self->texture, NULL, initial_atlas_size, initial_atlas_size, MGL_IMAGE_FORMAT_ALPHA, &load_options) != 0) {
             return -1;
         } else {
-            /*fprintf(stderr, "Error: failed to create font atlas texture, error: mgl_texture_load_from_memory failed\n");*/
+            /*fprintf(stderr, "mgl error: failed to create font atlas texture, error: mgl_texture_load_from_memory failed\n");*/
             self->font_atlas.width = initial_atlas_size;
             self->font_atlas.height = initial_atlas_size;
         }
diff --git a/src/graphics/image.c b/src/graphics/image.c
index eeee2ad..bb11334 100644
--- a/src/graphics/image.c
+++ b/src/graphics/image.c
@@ -46,7 +46,7 @@ int mgl_image_load_from_file(mgl_image *self, const char *filepath) {
     int format;
     self->data = stbi_load(filepath, &self->width, &self->height, &format, 0);
     if(!self->data) {
-        fprintf(stderr, "Error: failed to load image %s, error: %s\n", filepath, stbi_failure_reason());
+        fprintf(stderr, "mgl error: failed to load image %s, error: %s\n", filepath, stbi_failure_reason());
         mgl_image_unload(self);
         return -1;
     }
@@ -65,7 +65,7 @@ int mgl_image_load_from_memory(mgl_image *self, const unsigned char *data, size_
     int format;
     self->data = stbi_load_from_memory(data, size, &self->width, &self->height, &format, 0);
     if(!self->data) {
-        fprintf(stderr, "Error: failed to load image from memory, error: %s\n", stbi_failure_reason());
+        fprintf(stderr, "mgl error: failed to load image from memory, error: %s\n", stbi_failure_reason());
         mgl_image_unload(self);
         return -1;
     }
diff --git a/src/graphics/shader.c b/src/graphics/shader.c
index 8f44f0f..83c8407 100644
--- a/src/graphics/shader.c
+++ b/src/graphics/shader.c
@@ -25,7 +25,7 @@ static void print_compile_log(mgl_context *context, unsigned int shader_id, cons
     if(log_length > 0) {
         char *log_str = malloc(log_length + 1);
         if(!log_str) {
-            fprintf(stderr, "Error: failed to allocate memory for shader compile log\n");
+            fprintf(stderr, "mgl error: failed to allocate memory for shader compile log\n");
             return;
         }
 
@@ -47,7 +47,7 @@ static int mgl_shader_load_from_memory(mgl_shader *self, const unsigned char *sh
     mgl_context *context = mgl_get_context();
     self->id = context->gl.glCreateShader(mgl_shader_type_to_gl_shader_type(shader_type));
     if(self->id == 0) {
-        fprintf(stderr, "Error: failed to load shader, error: glCreateShader failed\n");
+        fprintf(stderr, "mgl error: failed to load shader, error: glCreateShader failed\n");
         return -1;
     }
 
@@ -57,12 +57,12 @@ static int mgl_shader_load_from_memory(mgl_shader *self, const unsigned char *sh
     int compiled_successfully = GL_FALSE;
     context->gl.glGetShaderiv(self->id, GL_COMPILE_STATUS, &compiled_successfully);
     if(compiled_successfully == GL_FALSE) {
-        print_compile_log(context, self->id, "Error");
+        print_compile_log(context, self->id, "mgl error");
         mgl_shader_unload(self);
         return -1;
     }
 
-    print_compile_log(context, self->id, "Warning");
+    print_compile_log(context, self->id, "mgl warning");
     return 0;
 }
 
@@ -72,12 +72,12 @@ static int mgl_shader_load_from_file(mgl_shader *self, const char *filepath, mgl
 
     mgl_filedata filedata;
     if(mgl_load_file(filepath, &filedata, NULL) != 0) {
-        fprintf(stderr, "Error: failed to load shader %s, error: mgl_load_file failed\n", filepath);
+        fprintf(stderr, "mgl error: failed to load shader %s, error: mgl_load_file failed\n", filepath);
         return -1;
     }
 
     if(filedata.size > INT32_MAX) {
-        fprintf(stderr, "Error: failed to load shader %s, error: shader size is too large\n", filepath);
+        fprintf(stderr, "mgl error: failed to load shader %s, error: shader size is too large\n", filepath);
         return -1;
     }
 
@@ -100,7 +100,7 @@ int mgl_shader_program_init(mgl_shader_program *self) {
     mgl_context *context = mgl_get_context();
     self->id = context->gl.glCreateProgram();
     if(self->id == 0) {
-        fprintf(stderr, "Error: failed to create shader program: error glCreateProgram failed\n");
+        fprintf(stderr, "mgl error: failed to create shader program: error glCreateProgram failed\n");
         return -1;
     }
 
@@ -143,7 +143,7 @@ static void print_link_log(mgl_context *context, unsigned int shader_id, const c
     if(log_length > 0) {
         char *log_str = malloc(log_length + 1);
         if(!log_str) {
-            fprintf(stderr, "Error: failed to allocate memory for shader link log\n");
+            fprintf(stderr, "mgl error: failed to allocate memory for shader link log\n");
             return;
         }
 
@@ -163,11 +163,11 @@ int mgl_shader_program_finalize(mgl_shader_program *self) {
     int is_linked = GL_TRUE;
     context->gl.glGetProgramiv(self->id, GL_LINK_STATUS, &is_linked);
     if(is_linked == GL_FALSE) {
-        print_link_log(context, self->id, "Error");
+        print_link_log(context, self->id, "mgl error");
         return -1;
     }
 
-    print_link_log(context, self->id, "Warning");
+    print_link_log(context, self->id, "mgl warning");
     return 0;
 }
 
@@ -179,7 +179,7 @@ int mgl_shader_program_set_uniform_float(mgl_shader_program *self, const char *u
     mgl_context *context = mgl_get_context();
     int uniform_location = context->gl.glGetUniformLocation(self->id, uniform_name);
     if(uniform_location == -1) {
-        fprintf(stderr, "Error: no uniform by the name %s was found in the shader\n", uniform_name);
+        fprintf(stderr, "mgl error: no uniform by the name %s was found in the shader\n", uniform_name);
         return -1;
     }
 
@@ -193,7 +193,7 @@ int mgl_shader_program_set_uniform_vec2f(mgl_shader_program *self, const char *u
     mgl_context *context = mgl_get_context();
     int uniform_location = context->gl.glGetUniformLocation(self->id, uniform_name);
     if(uniform_location == -1) {
-        fprintf(stderr, "Error: no uniform by the name %s was found in the shader\n", uniform_name);
+        fprintf(stderr, "mgl error: no uniform by the name %s was found in the shader\n", uniform_name);
         return -1;
     }
 
diff --git a/src/graphics/texture.c b/src/graphics/texture.c
index fb8c1e5..128d910 100644
--- a/src/graphics/texture.c
+++ b/src/graphics/texture.c
@@ -63,7 +63,7 @@ int mgl_texture_init(mgl_texture *self) {
     mgl_context *context = mgl_get_context();
     context->gl.glGenTextures(1, &self->id);
     if(self->id == 0) {
-        fprintf(stderr, "Error: failed to init texture (glGenTextures failed)\n");
+        fprintf(stderr, "mgl error: failed to init texture (glGenTextures failed)\n");
         return -1;
     }
 
diff --git a/src/mgl.c b/src/mgl.c
index dd5cccd..1fcbb4a 100644
--- a/src/mgl.c
+++ b/src/mgl.c
@@ -1,6 +1,7 @@
 #include "../include/mgl/mgl.h"
 #include <X11/Xutil.h>
 #include <X11/XKBlib.h>
+#include <X11/extensions/Xrender.h>
 #include <stdio.h>
 #ifndef NDEBUG
 #include <stdlib.h>
@@ -24,25 +25,47 @@ static int ignore_xioerror(Display *display) {
 
 static int glx_context_init() {
     const int attr[] = {
-        GLX_RGBA,
-        GLX_BUFFER_SIZE, 24,
-        GLX_DEPTH_SIZE, 0,
-        GLX_STENCIL_SIZE, 0,
+        GLX_RENDER_TYPE, GLX_RGBA_BIT,
+        GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT,
+        GLX_DOUBLEBUFFER, True,
         GLX_RED_SIZE, 8,
         GLX_GREEN_SIZE, 8,
         GLX_BLUE_SIZE, 8,
-        GLX_ALPHA_SIZE, 0,
-        GLX_ACCUM_RED_SIZE, 0,
-        GLX_ACCUM_GREEN_SIZE, 0,
-        GLX_ACCUM_BLUE_SIZE, 0,
-        GLX_ACCUM_ALPHA_SIZE, 0,
-        GLX_DOUBLEBUFFER, /* TODO: Add option to turn this off? */
+        GLX_ALPHA_SIZE, 8,
+        GLX_DEPTH_SIZE, 0,
         None
     };
 
-    context.visual_info = context.gl.glXChooseVisual(context.connection, DefaultScreen(context.connection), (int*)attr);
+    context.visual_info = NULL;
+    context.fbconfig = NULL;
+
+    int numfbconfigs = 0;
+    GLXFBConfig *fbconfigs = context.gl.glXChooseFBConfig(context.connection, DefaultScreen(context.connection), attr, &numfbconfigs);
+    for(int i = 0; i < numfbconfigs; i++) {
+        context.visual_info = context.gl.glXGetVisualFromFBConfig(context.connection, fbconfigs[i]);
+        if(!context.visual_info)
+            continue;
+
+        XRenderPictFormat *pict_format = XRenderFindVisualFormat(context.connection, ((XVisualInfo*)context.visual_info)->visual);
+        if(!pict_format) {
+            XFree(context.visual_info);
+            context.visual_info = NULL;
+            continue;
+        }
+
+        context.fbconfig = fbconfigs[i];
+        if(pict_format->direct.alphaMask > 0)
+            break;
+
+        XFree(context.visual_info);
+        context.visual_info = NULL;
+    }
+
+    if(fbconfigs)
+        XFree(fbconfigs);
+
     if(!context.visual_info) {
-        fprintf(stderr, "glXChooseVisual failed, no appropriate visual found\n");
+        fprintf(stderr, "mgl error: no appropriate visual found\n");
         return -1;
     }
 
@@ -61,7 +84,7 @@ int mgl_init(void) {
     if(init_count == 1) {
         context.connection = XOpenDisplay(NULL);
         if(!context.connection) {
-            fprintf(stderr, "XOpenDisplay(NULL) failed\n");
+            fprintf(stderr, "mgl error:XOpenDisplay(NULL) failed\n");
             mgl_deinit();
             return -1;
         }
@@ -120,7 +143,7 @@ void mgl_deinit(void) {
 mgl_context* mgl_get_context(void) {
 #ifndef NDEBUG
     if(init_count == 0) {
-        fprintf(stderr, "Error: mgl_get_context was called before mgl_init\n");
+        fprintf(stderr, "mgl error: mgl_get_context was called before mgl_init\n");
         abort();
     }
 #endif
diff --git a/src/window/window.c b/src/window/window.c
index 8acd428..eeb2e43 100644
--- a/src/window/window.c
+++ b/src/window/window.c
@@ -184,12 +184,12 @@ static void set_vertical_sync_enabled(Window window, int enabled) {
         static int warned = 0;
         if (!warned) {
             warned = 1;
-            fprintf(stderr, "Warning: setting vertical sync not supported\n");
+            fprintf(stderr, "mgl warning: setting vertical sync not supported\n");
         }
     }
 
     if(result != 0)
-        fprintf(stderr, "Warning: setting vertical sync failed\n");
+        fprintf(stderr, "mgl warning: setting vertical sync failed\n");
 }
 
 static void mgl_window_on_resize(mgl_window *self, int width, int height) {
@@ -223,13 +223,13 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
 
     self->context = malloc(sizeof(x11_context));
     if(!self->context) {
-        fprintf(stderr, "Failed to allocate x11 context\n");
+        fprintf(stderr, "mgl error: failed to allocate x11 context\n");
         return -1;
     }
 
     x11_context *x11_context = self->context;
     if(x11_context_init(x11_context) != 0) {
-        fprintf(stderr, "x11_context_init failed\n");
+        fprintf(stderr, "mgl error: x11_context_init failed\n");
         mgl_window_deinit(self);
         return -1;
     }
@@ -240,16 +240,16 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
     if(parent_window == 0)
         parent_window = DefaultRootWindow(context->connection);
 
-    x11_context->glx_context = context->gl.glXCreateContext(context->connection, context->visual_info, NULL, 1);
+    x11_context->glx_context = context->gl.glXCreateNewContext(context->connection, context->fbconfig, GLX_RGBA_TYPE, 0, True);
     if(!x11_context->glx_context) {
-        fprintf(stderr, "glXCreateContext failed\n");
+        fprintf(stderr, "mgl error: glXCreateContext failed\n");
         mgl_window_deinit(self);
         return -1;
     }
 
     x11_context->color_map = XCreateColormap(context->connection, DefaultRootWindow(context->connection), ((XVisualInfo*)context->visual_info)->visual, AllocNone);
     if(!x11_context->color_map) {
-        fprintf(stderr, "XCreateColormap failed\n");
+        fprintf(stderr, "mgl error: XCreateColormap failed\n");
         mgl_window_deinit(self);
         return -1;
     }
@@ -257,6 +257,8 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
     XSetWindowAttributes window_attr;
     window_attr.override_redirect = params ? params->override_redirect : false;
     window_attr.colormap = x11_context->color_map;
+    window_attr.background_pixmap = None;
+    window_attr.border_pixel = 0;
     window_attr.event_mask = 
         KeyPressMask | KeyReleaseMask |
         ButtonPressMask | ButtonReleaseMask |
@@ -266,8 +268,8 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
     const bool hide_window = params ? params->hidden : false;
 
     if(existing_window) {
-        if(!XChangeWindowAttributes(context->connection, existing_window, CWColormap | CWEventMask | CWOverrideRedirect, &window_attr)) {
-            fprintf(stderr, "XChangeWindowAttributes failed\n");
+        if(!XChangeWindowAttributes(context->connection, existing_window, CWColormap | CWEventMask | CWOverrideRedirect | CWBorderPixel | CWBackPixmap, &window_attr)) {
+            fprintf(stderr, "mgl error: XChangeWindowAttributes failed\n");
             mgl_window_deinit(self);
             return -1;
         }
@@ -279,9 +281,9 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
         self->window = XCreateWindow(context->connection, parent_window, params->position.x, params->position.y,
             window_size.x, window_size.y, 0,
             ((XVisualInfo*)context->visual_info)->depth, InputOutput, ((XVisualInfo*)context->visual_info)->visual,
-            CWColormap | CWEventMask | CWOverrideRedirect, &window_attr);
+            CWColormap | CWEventMask | CWOverrideRedirect | CWBorderPixel | CWBackPixmap, &window_attr);
         if(!self->window) {
-            fprintf(stderr, "XCreateWindow failed\n");
+            fprintf(stderr, "mgl error: XCreateWindow failed\n");
             mgl_window_deinit(self);
             return -1;
         }
@@ -310,7 +312,11 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
     XFlush(context->connection);
 
     /* TODO: Check for failure? */
-    context->gl.glXMakeCurrent(context->connection, self->window, x11_context->glx_context);
+    if(!context->gl.glXMakeContextCurrent(context->connection, self->window, self->window, x11_context->glx_context)) {
+        fprintf(stderr, "mgl error: failed to make opengl context current!\n");
+        mgl_window_deinit(self);
+        return -1;
+    }
     set_vertical_sync_enabled(self->window, 1);
     context->gl.glEnable(GL_TEXTURE_2D);
     context->gl.glEnable(GL_BLEND);
@@ -330,14 +336,14 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
 
     x11_context->xim = XOpenIM(context->connection, NULL, NULL, NULL);
     if(!x11_context->xim) {
-        fprintf(stderr, "XOpenIM failed\n");
+        fprintf(stderr, "mgl error: XOpenIM failed\n");
         mgl_window_deinit(self);
         return -1;
     }
 
     x11_context->xic = XCreateIC(x11_context->xim, XNInputStyle, XIMPreeditNothing | XIMStatusNothing, XNClientWindow, self->window, NULL);
     if(!x11_context->xic) {
-        fprintf(stderr, "XCreateIC failed\n");
+        fprintf(stderr, "mgl error: XCreateIC failed\n");
         mgl_window_deinit(self);
         return -1;
     }
@@ -893,7 +899,7 @@ void mgl_window_set_size_limits(mgl_window *self, mgl_vec2i minimum, mgl_vec2i m
         XFree(size_hints);
         XSync(context->connection, False);
     } else {
-        fprintf(stderr, "Warning: failed to set window size hints\n");
+        fprintf(stderr, "mgl warning: failed to set window size hints\n");
     }
 }
 
@@ -911,13 +917,13 @@ void mgl_window_set_clipboard(mgl_window *self, const char *str, size_t size) {
 
     /* Check if setting the selection owner was successful */
     if(XGetSelectionOwner(context->connection, x11_context->clipboard_atom) != self->window) {
-        fprintf(stderr, "Error: mgl_window_set_clipboard failed\n");
+        fprintf(stderr, "mgl error: mgl_window_set_clipboard failed\n");
         return;
     }
 
     self->clipboard_string = malloc(size + 1);
     if(!self->clipboard_string) {
-        fprintf(stderr, "Error: failed to allocate string for clipboard\n");
+        fprintf(stderr, "mgl error: failed to allocate string for clipboard\n");
         return;
     }
     memcpy(self->clipboard_string, str, size);
diff --git a/tests/main.c b/tests/main.c
index 7d94461..f1fad72 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -308,7 +308,7 @@ int main(int argc, char **argv) {
             }
         }
 
-        mgl_window_clear(&window, (mgl_color){0, 0, 0, 0});
+        mgl_window_clear(&window, (mgl_color){0, 0, 0, 255});
         draw(&window, &userdata);
         mgl_window_display(&window);
     }