+/**
+ * Override the context's version and/or API type if the
+ * environment variable MESA_GL_VERSION_OVERRIDE is set.
+ *
+ * Example uses of MESA_GL_VERSION_OVERRIDE:
+ *
+ * 2.1: select a compatibility (non-Core) profile with GL version 2.1
+ * 3.0: select a compatibility (non-Core) profile with GL version 3.0
+ * 3.0FC: select a Core+Forward Compatible profile with GL version 3.0
+ * 3.1: select a Core profile with GL version 3.1
+ * 3.1FC: select a Core+Forward Compatible profile with GL version 3.1
+ */
+void
+_mesa_override_gl_version(struct gl_context *ctx)
+{
+ const char *env_var = "MESA_GL_VERSION_OVERRIDE";
+ const char *version;
+ int n;
+ int major, minor;
+ GLboolean fc_suffix;
+
+ version = getenv(env_var);
+ if (!version) {
+ return;
+ }
+
+ fc_suffix = check_for_ending(version, "FC");
+
+ n = sscanf(version, "%u.%u", &major, &minor);
+ if (n != 2) {
+ fprintf(stderr, "error: invalid value for %s: %s\n", env_var, version);
+ } else {
+ ctx->Version = major * 10 + minor;
+ if (ctx->Version < 30 && fc_suffix) {
+ fprintf(stderr, "error: invalid value for %s: %s\n", env_var, version);
+ } else {
+ if (ctx->Version >= 30 && fc_suffix) {
+ ctx->API = API_OPENGL_CORE;
+ ctx->Const.ContextFlags |= GL_CONTEXT_FLAG_FORWARD_COMPATIBLE_BIT;
+ } else if (ctx->Version >= 31) {
+ ctx->API = API_OPENGL_CORE;
+ } else {
+ ctx->API = API_OPENGL;
+ }
+ create_version_string(ctx, "");
+ }
+ }
+}
+