[gtk+] gsk: Use the appropriate GLSL version

[Emmanuele Bassi <ebassi src gnome org>]

commit 02c615cc34e51a3b5661b79372f09749b845e864
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Tue Nov 1 15:00:31 2016 +0000

    gsk: Use the appropriate GLSL version
    
    The GLSL versions are:
    
      OpenGL 2.1: #version 110
      OpenGL 3.0: #version 130
      OpenGL 3.2: #version 150
    
      OpenGLES 2.0: #version 100
      OpenGLES 3.0: #version 300 es
    
    So we need to check the version of the GdkGLContext if we want use the
    appropriate version, especially for legacy OpenGL contexts, which can be
    both 3.x and 2.x.

 gsk/gskglrenderer.c |   14 +++++++++++---
 1 files changed, 11 insertions(+), 3 deletions(-)
---
diff --git a/gsk/gskglrenderer.c b/gsk/gskglrenderer.c
index c4eec60..0808caa 100644
--- a/gsk/gskglrenderer.c
+++ b/gsk/gskglrenderer.c
@@ -16,8 +16,9 @@
 
 #include <epoxy/gl.h>
 
-#define SHADER_VERSION_GLES             110
-#define SHADER_VERSION_GL_LEGACY        120
+#define SHADER_VERSION_GLES             100
+#define SHADER_VERSION_GL2_LEGACY       110
+#define SHADER_VERSION_GL3_LEGACY       130
 #define SHADER_VERSION_GL3              150
 
 typedef struct {
@@ -213,7 +214,14 @@ gsk_gl_renderer_create_programs (GskGLRenderer *self)
     }
   else if (gdk_gl_context_is_legacy (self->gl_context))
     {
-      gsk_shader_builder_set_version (builder, SHADER_VERSION_GL_LEGACY);
+      int maj, min;
+      gdk_gl_context_get_version (self->gl_context, &maj, &min);
+
+      if (maj == 3)
+        gsk_shader_builder_set_version (builder, SHADER_VERSION_GL3_LEGACY);
+      else
+        gsk_shader_builder_set_version (builder, SHADER_VERSION_GL2_LEGACY);
+
       gsk_shader_builder_set_vertex_preamble (builder, "gl_common.vs.glsl");
       gsk_shader_builder_set_fragment_preamble (builder, "gl_common.fs.glsl");
       gsk_shader_builder_add_define (builder, "GSK_LEGACY", "1");