main: Allow for the possibility of GL 3.2 without ARB_geometry_shader4.

Previously, we assumed that the only way Mesa would expose geometry
shader support was via the ARB_geometry_shader4 extension.  But this
extension has some extra complications over GL 3.2 (interactions with
compatibility-only features, and link-time initialization of the
constant gl_VerticesIn).  So we want to allow for the possibility of
supporting GL 3.2 (with GLSL 1.50 style geometry shaders) even if
ctx->Extensions.ARB_geometry_shader4 is false.

This patch adds a new function, _mesa_has_geometry_shaders(), which
returns true if either ARB_geometry_shader4 is supported or the GL
version is at least 3.2 desktop.  Since compute_version() only enables
GL 3.2 functionality when GLSL 1.50 support is present, a sufficient
way for a back-end to advertise geometry shader support is to set
ctx->Const.GLSLVersion >= 150.

v2: Remove unnecessary ctx->Const.GeometryShaders150 constant.

Reviewed-by: Ian Romanick <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>

1 files changed, 0 insertions, 1 deletions

diff --git a/src/mesa/main/version.c b/src/mesa/main/version.c
index ab9b14c026e..55411faf8c5 100644
--- a/src/mesa/main/version.c
+++ b/src/mesa/main/version.c
@@ -262,7 +262,6 @@ compute_version(struct gl_context *ctx)
                               ctx->Extensions.ARB_depth_clamp &&
                               ctx->Extensions.ARB_draw_elements_base_vertex &&
                               ctx->Extensions.ARB_fragment_coord_conventions &&
-                              ctx->Extensions.ARB_geometry_shader4 &&
                               ctx->Extensions.EXT_provoking_vertex &&
                               ctx->Extensions.ARB_seamless_cube_map &&
                               ctx->Extensions.ARB_sync &&