+static void
+output_if_debug(const char *prefixString, const char *outputString,
+ GLboolean newline)
+{
+ static int debug = -1;
+
+ /* Check the MESA_DEBUG environment variable if it hasn't
+ * been checked yet. We only have to check it once...
+ */
+ if (debug == -1) {
+ char *env = _mesa_getenv("MESA_DEBUG");
+
+ /* In a debug build, we print warning messages *unless*
+ * MESA_DEBUG is 0. In a non-debug build, we don't
+ * print warning messages *unless* MESA_DEBUG is
+ * set *to any value*.
+ */
+#ifdef DEBUG
+ debug = (env != NULL && _mesa_atoi(env) == 0) ? 0 : 1;
+#else
+ debug = (env != NULL) ? 1 : 0;
+#endif
+ }
+
+ /* Now only print the string if we're required to do so. */
+ if (debug) {
+ fprintf(stderr, "%s: %s", prefixString, outputString);
+ if (newline)
+ fprintf(stderr, "\n");
+
+#if defined(_WIN32) && !defined(_WIN32_WCE)
+ /* stderr from windows applications without console is not usually
+ * visible, so communicate with the debugger instead */
+ {
+ char buf[4096];
+ _mesa_snprintf(buf, sizeof(buf), "%s: %s%s", prefixString, outputString, newline ? "\n" : "");
+ OutputDebugStringA(buf);
+ }
+#endif
+ }
+}
+
+
+/**
+ * Return string version of GL error code.
+ */
+static const char *
+error_string( GLenum error )
+{
+ switch (error) {
+ case GL_NO_ERROR:
+ return "GL_NO_ERROR";
+ case GL_INVALID_VALUE:
+ return "GL_INVALID_VALUE";
+ case GL_INVALID_ENUM:
+ return "GL_INVALID_ENUM";
+ case GL_INVALID_OPERATION:
+ return "GL_INVALID_OPERATION";
+ case GL_STACK_OVERFLOW:
+ return "GL_STACK_OVERFLOW";
+ case GL_STACK_UNDERFLOW:
+ return "GL_STACK_UNDERFLOW";
+ case GL_OUT_OF_MEMORY:
+ return "GL_OUT_OF_MEMORY";
+ case GL_TABLE_TOO_LARGE:
+ return "GL_TABLE_TOO_LARGE";
+ case GL_INVALID_FRAMEBUFFER_OPERATION_EXT:
+ return "GL_INVALID_FRAMEBUFFER_OPERATION";
+ default:
+ return "unknown";
+ }
+}
+
+
+/**
+ * When a new type of error is recorded, print a message describing
+ * previous errors which were accumulated.
+ */
+static void
+flush_delayed_errors( GLcontext *ctx )
+{
+ char s[MAXSTRING];
+
+ if (ctx->ErrorDebugCount) {
+ _mesa_snprintf(s, MAXSTRING, "%d similar %s errors",
+ ctx->ErrorDebugCount,
+ error_string(ctx->ErrorValue));
+
+ output_if_debug("Mesa", s, GL_TRUE);
+
+ ctx->ErrorDebugCount = 0;
+ }
+}
+
+