fix: add debug capabilities for gl and egl

src/shaders.c

@@ -26,7 +26,7 @@
 
 static const GLuint unused_uniform = (GLuint)-1;
 
-bool check_glerror_ro(const char *context) {
+static bool check_glerror_ro(const char *context) {
   unsigned int code;
 
   code = glGetError();
@@ -39,7 +39,7 @@ bool check_glerror_ro(const char *context) {
   return false;
 }
 
-bool check_glerror(ShaderProgram *program, const char *context) {
+static bool check_glerror(ShaderProgram *program, const char *context) {
   if (check_glerror_ro(context)) {
     program->error = true;
     return true;
@@ -47,7 +47,20 @@ bool check_glerror(ShaderProgram *program, const char *context) {
   return false;
 }
 
-bool check_eglerror_ro(const char *context) {
+#ifdef GL_DEBUG
+
+static void gl_debug_callback(GLenum source, GLenum type, GLuint id,
+                              GLenum severity,
+                              __attribute__((unused)) GLsizei length,
+                              const GLchar *message,
+                              __attribute__((unused)) const void *userParam) {
+  log_debug("GL Debug: source=%x, type=%x, id=%d, severity=%x, message=%s",
+            source, type, id, severity, message ? message : "(null)");
+}
+
+#endif /* GL_DEBUG */
+
+static bool check_eglerror_ro(const char *context) {
 #ifdef VIDEO_IN
   unsigned int code;
 
@@ -61,7 +74,7 @@ bool check_eglerror_ro(const char *context) {
   return false;
 }
 
-bool check_eglerror(ShaderProgram *program, const char *context) {
+static bool check_eglerror(ShaderProgram *program, const char *context) {
   if (check_eglerror_ro(context)) {
     program->error = true;
     return true;
@@ -69,9 +82,29 @@ bool check_eglerror(ShaderProgram *program, const char *context) {
   return false;
 }
 
+#ifdef VIDEO_IN
+#ifdef EGL_DEBUG
+
+static void egl_debug_callback(EGLenum error, const char *command,
+                               EGLint messageType, EGLLabelKHR threadLabel,
+                               EGLLabelKHR objectLabel, const char *message) {
+  log_debug("EGL Debug: error=%04x, command=%s, type=%d, "
+            "thread=%p, object=%p, message=%s",
+            error, command ? command : "(null)", messageType, threadLabel,
+            objectLabel, message ? message : "(null)");
+}
+
+#endif /* EGL_DEBUG */
+#endif /* VIDEO_IN */
+
 static bool init_gl(ShaderProgram *program) {
   gladLoadGL(glfwGetProcAddress);
 
+#ifdef GL_DEBUG
+  glEnable(GL_DEBUG_OUTPUT);
+  glDebugMessageCallback(gl_debug_callback, NULL);
+#endif /* GL_DEBUG */
+
 #ifdef VIDEO_IN
   program->egl_display = glfwGetEGLDisplay();
   if (program->egl_display == EGL_NO_DISPLAY) {
@@ -81,6 +114,20 @@ static bool init_gl(ShaderProgram *program) {
   }
 
   gladLoadEGL(program->egl_display, glfwGetProcAddress);
+
+#ifdef EGL_DEBUG
+  {
+    PFNEGLDEBUGMESSAGECONTROLKHRPROC debug_ctrl =
+        (PFNEGLDEBUGMESSAGECONTROLKHRPROC)glfwGetProcAddress(
+            "eglDebugMessageControlKHR");
+    if (debug_ctrl != NULL) {
+      const EGLAttrib attrib_list[] = {EGL_NONE};
+      debug_ctrl(egl_debug_callback, attrib_list);
+    }
+  }
+
+#endif /* EGL_DEBUG */
+
 #endif /* VIDEO_IN */
 
   return !check_glerror(program, "init_gl") &&