renderer: Add cogl_renderer_get_n_fragment_texture_units()

Add a method on the renderer to know how many texture image units are
accessible from fragment shaders.

https://bugzilla.gnome.org/show_bug.cgi?id=657347

Reviewed-by: Robert Bragg <robert@linux.intel.com>

cogl/cogl-renderer.c

@@ -35,6 +35,7 @@
 #include "cogl-internal.h"
 #include "cogl-private.h"
 #include "cogl-object.h"
+#include "cogl-context-private.h"
 
 #include "cogl-renderer.h"
 #include "cogl-renderer-private.h"
@@ -394,3 +395,18 @@ _cogl_renderer_get_proc_address (CoglRenderer *renderer,
 
   return winsys->renderer_get_proc_address (renderer, name);
 }
+
+int
+cogl_renderer_get_n_fragment_texture_units (CoglRenderer *renderer)
+{
+  int n = 0;
+
+  _COGL_GET_CONTEXT (ctx, 0);
+
+#if defined (HAVE_COGL_GL) || defined (HAVE_COGL_GLES2)
+  if (ctx->driver == COGL_DRIVER_GL || ctx->driver == COGL_DRIVER_GLES2)
+    GE (ctx, glGetIntegerv (GL_MAX_TEXTURE_IMAGE_UNITS, &n));
+#endif
+
+  return n;
+}

cogl/cogl-renderer.h

@@ -114,6 +114,22 @@ cogl_renderer_set_winsys_id (CoglRenderer *renderer,
 CoglWinsysID
 cogl_renderer_get_winsys_id (CoglRenderer *renderer);
 
+/**
+ * cogl_renderer_get_n_fragment_texture_units:
+ * @renderer: A #CoglRenderer
+ *
+ * Queries how many texture units can be used from fragment programs
+ *
+ * Returns: the number of texture image units.
+ *
+ * Since: 1.8
+ * Stability: Unstable
+ */
+#define cogl_renderer_get_n_fragment_texture_units \
+  cogl_renderer_get_n_fragment_texture_units_EXP
+int
+cogl_renderer_get_n_fragment_texture_units (CoglRenderer *renderer);
+
 #define cogl_renderer_check_onscreen_template \
   cogl_renderer_check_onscreen_template_EXP
 gboolean

doc/reference/cogl-2.0-experimental/cogl-2.0-experimental-sections.txt

@@ -14,6 +14,7 @@ cogl_object_set_user_data
 <FILE>cogl-renderer</FILE>
 <TITLE>CoglRenderer: Connect to a backend renderer</TITLE>
 cogl_renderer_new
+cogl_renderer_get_n_fragment_texture_units
 cogl_renderer_connect
 
 <SUBSECTION>