[Mesa-dev] [PATCH v2 3/5] mesa: simplify MESA_GL_VERSION_OVERRIDE behavior of API override

[Andres Gomez]

From: Marek Olšák <marek.olsak at amd.com>

v2:
 - Provide a correct explanation on the envvars documentation (Ian).
 - Provide a more correct explanation on the function comments (Andres).

Fixes: 2599b92eb97 ("mesa: allow forcing >=3.1 compatibility contexts
with MESA_GL_VERSION_OVERRIDE")

Cc: Jordan Justen <jordan.l.justen at intel.com>
Cc: Ian Romanick <ian.d.romanick at intel.com>
Cc: Eric Engestrom <eric.engestrom at imgtec.com>
Cc: Emil Velikov <emil.velikov at collabora.com>
Signed-off-by: Andres Gomez <agomez at igalia.com>
---
 docs/envvars.html       | 25 ++++++++++++++++++-------
 src/mesa/main/version.c | 23 +++++++++++------------
 2 files changed, 29 insertions(+), 19 deletions(-)

diff --git a/docs/envvars.html b/docs/envvars.html
index ea42a50779b..7ec91a1fd91 100644
--- a/docs/envvars.html
+++ b/docs/envvars.html
@@ -88,19 +88,30 @@ This is a work-around for that.
 <li>MESA_GL_VERSION_OVERRIDE - changes the value returned by
 glGetString(GL_VERSION) and possibly the GL API type.
 <ul>
-<li> The format should be MAJOR.MINOR[FC]
+<li> The format should be MAJOR.MINOR[FC|COMPAT]
 <li> FC is an optional suffix that indicates a forward compatible context.
 This is only valid for versions >= 3.0.
-<li> GL versions < 3.0 are set to a compatibility (non-Core) profile
-<li> GL versions = 3.0, see below
-<li> GL versions > 3.0 are set to a Core profile
-<li> Examples: 2.1, 3.0, 3.0FC, 3.1, 3.1FC
+<li> COMPAT is an optional suffix that indicates a compatibility
+context or GL_ARB_compatibility support. This is only valid for
+versions >= 3.1.
+<li> GL versions <= 3.0 are set to a compatibility (non-Core) profile
+<li> GL versions = 3.1, depending on the driver, it may or may not
+have the ARB_compatibility extension enabled.
+<li> GL versions >= 3.2 are set to a Core profile
+<li> Examples: 2.1, 3.0, 3.0FC, 3.1, 3.1FC, 3.1COMPAT, 3.2, 3.2FC, 3.2COMPAT
 <ul>
 <li> 2.1 - select a compatibility (non-Core) profile with GL version 2.1
 <li> 3.0 - select a compatibility (non-Core) profile with GL version 3.0
 <li> 3.0FC - select a Core+Forward Compatible profile with GL version 3.0
-<li> 3.1 - select a Core profile with GL version 3.1
-<li> 3.1FC - select a Core+Forward Compatible profile with GL version 3.1
+<li> 3.1 - select OpenGL 3.1. GL_ARB_compatibility will be enabled per
+the driver default.
+<li> 3.1FC - select OpenGL 3.1 with forward compatibility
+enabled. GL_ARB_compatibilty will not be enabled.
+<li> 3.1COMPAT - select OpenGL 3.1 with GL_ARB_compatibilty forced
+enabled.
+<li> 3.2 - select a Core profile with GL version 3.2
+<li> 3.2FC - select a Core+Forward Compatible profile with GL version 3.2
+<li> 3.2COMPAT - select a compatibility (non-Core) profile with GL version 3.2
 </ul>
 <li> Mesa may not really implement all the features of the given version.
 (for developers only)
diff --git a/src/mesa/main/version.c b/src/mesa/main/version.c
index a28069054d3..ac8dd9b9e43 100644
--- a/src/mesa/main/version.c
+++ b/src/mesa/main/version.c
@@ -139,11 +139,15 @@ create_version_string(struct gl_context *ctx, const char *prefix)
  *
  * 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
+ * 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 GL version 3.1 with GL_ARB_compatibility enabled per the driver default.
+ * 3.1FC: select GL version 3.1 with forward compatibility and GL_ARB_compatibility disabled.
+ * 3.1COMPAT: select GL version 3.1 with GL_ARB_compatibilty enabled.
+ * X.Y: override GL version to X.Y without changing the profile.
+ * X.YFC: select a Core+Forward Compatible profile with GL version X.Y.
+ * X.YCOMPAT: select a Compatibility profile with GL version X.Y.
  */
 bool
 _mesa_override_gl_version_contextless(struct gl_constants *consts,
@@ -157,17 +161,12 @@ _mesa_override_gl_version_contextless(struct gl_constants *consts,
    if (version > 0) {
       *versionOut = version;
 
-      /* If the API is a desktop API, adjust the context flags.  We may also
-       * need to modify the API depending on the version.  For example, Mesa
-       * does not support a GL 3.3 compatibility profile.
-       */
+      /* Modify the API and context flags as needed. */
       if (*apiOut == API_OPENGL_CORE || *apiOut == API_OPENGL_COMPAT) {
          if (version >= 30 && fwd_context) {
             *apiOut = API_OPENGL_CORE;
             consts->ContextFlags |= GL_CONTEXT_FLAG_FORWARD_COMPATIBLE_BIT;
-         } else if (version >= 31 && !compat_context) {
-            *apiOut = API_OPENGL_CORE;
-         } else {
+         } else if (compat_context) {
             *apiOut = API_OPENGL_COMPAT;
          }
       }
-- 
2.16.1