[gtk/check-half-float] gsk: Check for half float support

[Matthias Clasen <matthiasc src gnome org>]

commit 97440784448e58878cf6011fe6fffb1bc4193e80
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu May 5 13:09:26 2022 -0400

    gsk: Check for half float support
    
    The GL renderer currently relies on half float support
    in vertex buffers, so check that we have it.
    
    Related: #4894

 gsk/gl/gskglrenderer.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)
---
diff --git a/gsk/gl/gskglrenderer.c b/gsk/gl/gskglrenderer.c
index d1b40d225e..4e7b18c6b2 100644
--- a/gsk/gl/gskglrenderer.c
+++ b/gsk/gl/gskglrenderer.c
@@ -24,6 +24,7 @@
 #include <gdk/gdkdisplayprivate.h>
 #include <gdk/gdkglcontextprivate.h>
 #include <gdk/gdksurfaceprivate.h>
+#include <gdk/gdkintl.h>
 #include <gsk/gskdebugprivate.h>
 #include <gsk/gskrendererprivate.h>
 #include <gsk/gskrendernodeprivate.h>
@@ -115,6 +116,20 @@ gsk_gl_renderer_realize (GskRenderer  *renderer,
   if (!context || !gdk_gl_context_realize (context, error))
     goto failure;
 
+  if (!gdk_gl_context_has_vertex_half_float (context))
+    {
+      GdkGLAPI api;
+      int major, minor;
+
+      api = gdk_gl_context_get_api (context);
+      gdk_gl_context_get_version (context, &major, &minor);
+      g_set_error (error,
+                   GDK_GL_ERROR, GDK_GL_ERROR_NOT_AVAILABLE,
+                   _("This %s %d.%d implementation does not support half-float vertex data"),
+                   api == GDK_GL_API_GL ? "GL" : "GLES", major, minor);
+      goto failure;
+    }
+
 #ifdef G_ENABLE_DEBUG
   if (GSK_RENDERER_DEBUG_CHECK (GSK_RENDERER (self), SHADERS))
     debug_shaders = TRUE;
@@ -331,7 +346,7 @@ gsk_gl_renderer_render_texture (GskRenderer           *renderer,
         {
           for (x = 0; x < width; x += max_size)
             {
-              texture = gsk_gl_renderer_render_texture (renderer, root, 
+              texture = gsk_gl_renderer_render_texture (renderer, root,
                                                         &GRAPHENE_RECT_INIT (x, y,
                                                                              MIN (max_size, 
viewport->size.width - x),
                                                                              MIN (max_size, 
viewport->size.height - y)));