gl/colorconvert: fix up alpha clobbering

Previously it would only work if the alpha value was in the last
component (RGBx, BGRx).  Now it works wherever the alpha value may
be (xRGB, xBGR, etc).

diff --git a/gst-libs/gst/gl/gstglcolorconvert.c b/gst-libs/gst/gl/gstglcolorconvert.c
index 643bbff..f9055be 100644 (file)
--- a/gst-libs/gst/gl/gstglcolorconvert.c
+++ b/gst-libs/gst/gl/gstglcolorconvert.c
@@ -133,7 +133,7 @@ static const gchar frag_REORDER[] =
       "void main(void)\n"
       "{\n"
       " vec4 t = texture2D(tex, v_texcoord * tex_scale0);\n"
-      " %s;\n" /* clobber alpha channel? */
+      " %s\n" /* clobber alpha channel? */
       " gl_FragColor = vec4(t.%c, t.%c, t.%c, t.%c);\n"
       "}";
 
@@ -674,15 +674,17 @@ _RGB_to_RGB (GstGLColorConvert * convert)
   GstVideoFormat out_format = GST_VIDEO_INFO_FORMAT (&convert->out_info);
   const gchar *out_format_str = gst_video_format_to_string (out_format);
   gchar *pixel_order = _RGB_pixel_order (in_format_str, out_format_str);
-  const gchar *alpha = "";
+  gchar *alpha = NULL;
 
   info->in_n_textures = 1;
   info->out_n_textures = 1;
   if (_is_RGBx (in_format))
-    alpha = "t.a = 1.0";
-  info->frag_prog = g_strdup_printf (frag_REORDER, alpha, pixel_order[0],
-      pixel_order[1], pixel_order[2], pixel_order[3]);
+    alpha = g_strdup_printf ("t.%c = 1.0;", pixel_order[3]);
+  info->frag_prog = g_strdup_printf (frag_REORDER, alpha ? alpha : "",
+      pixel_order[0], pixel_order[1], pixel_order[2], pixel_order[3]);
   info->shader_tex_names[0] = "tex";
+
+  g_free (alpha);
 }
 
 static void
@@ -855,23 +857,25 @@ _RGB_to_GRAY (GstGLColorConvert * convert)
   GstVideoFormat in_format = GST_VIDEO_INFO_FORMAT (&convert->in_info);
   const gchar *in_format_str = gst_video_format_to_string (in_format);
   gchar *pixel_order = _RGB_pixel_order (in_format_str, "rgba");
-  const gchar *alpha = "";
+  gchar *alpha = NULL;
 
   info->in_n_textures = 1;
   info->out_n_textures = 1;
   info->shader_tex_names[0] = "tex";
 
   if (_is_RGBx (in_format))
-    alpha = "t.a = 1.0";
+    alpha = g_strdup_printf ("t.%c = 1.0;", pixel_order[3]);
 
   switch (GST_VIDEO_INFO_FORMAT (&convert->out_info)) {
     case GST_VIDEO_FORMAT_GRAY8:
-      info->frag_prog = g_strdup_printf (frag_REORDER, alpha, pixel_order[0],
-          pixel_order[0], pixel_order[0], pixel_order[3]);
+      info->frag_prog = g_strdup_printf (frag_REORDER, alpha ? alpha : "",
+          pixel_order[0], pixel_order[0], pixel_order[0], pixel_order[3]);
       break;
     default:
       break;
   }
+
+  g_free (alpha);
 }
 
 static void