vrend: manual clear_color srgb encoding for eglimage-backed bgr* textures

Since eglimage-backed textures don't support glTextureView(), colorspace
conversion must be applied manually on the clear_color vector. Also, if
the view intended to swizzle, we need to do that manually as well.

Signed-off-by: Ryan Neph <ryanneph@google.com>
Reviewed-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/725>

src/vrend_renderer.c

@@ -3987,22 +3987,28 @@ void vrend_clear(struct vrend_context *ctx,
    float colorf[4];
    memcpy(colorf, color->f, sizeof(colorf));
 
-   if (sub_ctx->nr_cbufs && sub_ctx->surf[0] &&
+   {
-       vrend_resource_has_24bpp_internal_format(sub_ctx->surf[0]->texture) &&
+      struct vrend_surface *surf = sub_ctx->surf[0];
-       util_format_is_srgb(sub_ctx->surf[0]->format)) {
+      if (sub_ctx->nr_cbufs && surf &&
+          util_format_is_srgb(surf->format) &&
+          !vrend_resource_supports_view(surf->texture, surf->format)) {
          VREND_DEBUG(dbg_tex, ctx,
                      "manually converting glClearColor from linear->srgb colorspace for EGL-backed framebuffer color attachment"
                      " (surface format is %s; resource format is %s)\n",
-                  util_format_name(sub_ctx->surf[0]->format),
+                     util_format_name(surf->format),
-                  util_format_name(sub_ctx->surf[0]->texture->base.format));
+                     util_format_name(surf->texture->base.format));
          for (int i = 0; i < 3; ++i) // i < 3: don't convert alpha channel
             colorf[i] = vrend_color_convert_linear_to_srgb(colorf[i]);
       }
+   }
 
    if (buffers & PIPE_CLEAR_COLOR) {
       if (sub_ctx->nr_cbufs && sub_ctx->surf[0] && vrend_format_is_emulated_alpha(sub_ctx->surf[0]->format)) {
          glClearColor(colorf[3], 0.0, 0.0, 0.0);
-      } else if (sub_ctx->nr_cbufs && sub_ctx->surf[0] && vrend_resource_is_emulated_bgra(sub_ctx->surf[0]->texture)) {
+      } else if (sub_ctx->nr_cbufs && sub_ctx->surf[0] &&
+                 !vrend_resource_supports_view(sub_ctx->surf[0]->texture,
+                                               sub_ctx->surf[0]->format) &&
+                 !vrend_format_is_bgra(sub_ctx->surf[0]->format)) {
          VREND_DEBUG(dbg_bgra, ctx, "swizzling glClearColor() since rendering surface is an externally-stored BGR* resource\n");
          glClearColor(colorf[2], colorf[1], colorf[0], colorf[3]);
       } else {