st/wgl: add debug code to check that pixel format initialization worked

If the assertion fails, it means something is really broken.  Before,
if this happened we reverted to the GDI renderer without any warning.

Reviewed-by: Matthew McClure <mcclurem@vmware.com>

diff --git a/src/gallium/state_trackers/wgl/stw_pixelformat.c b/src/gallium/state_trackers/wgl/stw_pixelformat.c
index dc5160d..96169e2 100644 (file)
--- a/src/gallium/state_trackers/wgl/stw_pixelformat.c
+++ b/src/gallium/state_trackers/wgl/stw_pixelformat.c
@@ -214,13 +214,14 @@ stw_pixelformat_add(
 /**
  * Add the depth/stencil/accum/ms variants for a particular color format.
  */
-static void
+static unsigned
 add_color_format_variants(const struct stw_pf_color_info *color,
                           boolean extended)
 {
    struct pipe_screen *screen = stw_dev->screen;
    unsigned ms, db, ds, acc;
    unsigned bind_flags = PIPE_BIND_RENDER_TARGET;
+   unsigned num_added = 0;
 
    if (!extended) {
       bind_flags |= PIPE_BIND_DISPLAY_TARGET;
@@ -228,7 +229,7 @@ add_color_format_variants(const struct stw_pf_color_info *color,
 
    if (!screen->is_format_supported(screen, color->format,
                                     PIPE_TEXTURE_2D, 0, bind_flags)) {
-      return;
+      return 0;
    }
 
    for (ms = 0; ms < Elements(stw_pf_multisample); ms++) {
@@ -253,10 +254,13 @@ add_color_format_variants(const struct stw_pf_color_info *color,
             for (acc = 0; acc < 2; acc++) {
                stw_pixelformat_add(stw_dev, extended, color, depth,
                                    acc * 16, doublebuffer, samples);
+               num_added++;
             }
          }
       }
    }
+
+   return num_added;
 }
 
 
@@ -264,14 +268,16 @@ void
 stw_pixelformat_init( void )
 {
    unsigned i;
+   unsigned num_formats = 0;
 
    assert( !stw_dev->pixelformat_count );
    assert( !stw_dev->pixelformat_extended_count );
 
    /* normal, displayable formats */
    for (i = 0; i < Elements(stw_pf_color); i++) {
-      add_color_format_variants(&stw_pf_color[i], FALSE);
+      num_formats += add_color_format_variants(&stw_pf_color[i], FALSE);
    }
+   assert(num_formats > 0);
 
    /* extended, pbuffer-only formats */
    for (i = 0; i < Elements(stw_pf_color_extended); i++) {