From fba4823a916b63f279955dbe6d98b6efc666f53e Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Fri, 28 Aug 2015 01:43:23 -0700 Subject: [PATCH] i965: Don't do legacy userclipping in non-compatibility contexts. According to the GLSL 1.50 specification, page 76: "The shader must also set all values in gl_ClipDistance that have been enabled via the OpenGL API, or results are undefined." With this patch, we only enable clip distance writes when the shader actually writes them. We no longer force a value to be written when clip planes are enabled in the API. This could mean the first varying slot would be used as clip distances - I believe it should be the safe kind of undefined behavior. Empirically, it doesn't seem to cause a problem. Signed-off-by: Kenneth Graunke Reviewed-by: Chris Forbes --- src/mesa/drivers/dri/i965/brw_vs.c | 1 + 1 file changed, 1 insertion(+) diff --git a/src/mesa/drivers/dri/i965/brw_vs.c b/src/mesa/drivers/dri/i965/brw_vs.c index df7e531..05457d4 100644 --- a/src/mesa/drivers/dri/i965/brw_vs.c +++ b/src/mesa/drivers/dri/i965/brw_vs.c @@ -308,6 +308,7 @@ brw_vs_populate_key(struct brw_context *brw, key->program_string_id = vp->id; if (ctx->Transform.ClipPlanesEnabled != 0 && + ctx->API == API_OPENGL_COMPAT && !vp->program.Base.UsesClipDistanceOut) { key->nr_userclip_plane_consts = _mesa_logbase2(ctx->Transform.ClipPlanesEnabled) + 1; -- 2.7.4