Note in the README that OpenGL 3.0 is sufficient.

diff --git a/README b/README
index 8a85fb4af61fa0daf5f00caaea89b3b86fc6fab9..81bb4c99e2f8428cca5b417c6fd7801c17a57103 100644 (file)
--- a/README
+++ b/README
@@ -21,9 +21,10 @@ OK, you need
   works fine on Linux and OS X, and Movit is not very POSIX-bound.)
 * GNU Make.
 * A GPU capable of running GLSL fragment shaders,
-  process floating-point textures, and a few other things. If your machine
-  is less than five years old _and you have the appropriate drivers_,
-  you're home free.
+  processing floating-point textures, and a few other things (all are
+  part of OpenGL 3.0 or newer, although most OpenGL 2.0 cards also
+  have what's needed through extensions). If your machine is less than five
+  years old _and you have the appropriate drivers_, you're home free.
 * The [Eigen 3] and [Google Test] libraries. (The library itself
   depends only on the former, but you probably want to run the unit tests.)
 * The [epoxy] library, for dealing with OpenGL extensions on various
@@ -53,7 +54,8 @@ all research-grade problems, and Movit is currently not there.)
 TL;DR, but I am interested in a programming example instead
 ===========================================================
 
-Assuming you have an OpenGL context already set up:
+Assuming you have an OpenGL context already set up (currently you need
+a classic OpenGL context; a GL 3.2+ core context won't do):
 
 <code>
   using namespace movit;