[Mesa-dev] [PATCH v2 2/3] mesa/st: enable EXT_sRGB_write_control for drivers that support it

[Gert Wollny]

From: Gert Wollny <gert.wollny at collabora.com>

With this patch the extension EXT_sRGB_write_control is enabled for
gallium drivers that support sRGB formats as render targets.

Tested (and pass) on r600 (evergreen) and softpipe:

  dEQP-GLES31.functional.fbo.srgb_write_control.framebuffer_srgb_enabled*

with "MESA_GLES_VERSION_OVERRIDE=3.2" (the tests needlessly check for this), and

  dEQP-GLES31.functional.fbo.srgb_write_control.framebuffer_srgb_unsupported_enum

when extension is manually disabled via MESA_EXTENSION_OVERRIDE

v2: - always enable the extension when sRGB is supported (Ilia Mirkin).
    - Correct handling by moving extension initialization to the
      place where gallium/st actually takes care of this. This also
      fixes properly disabling the extension via MESA_EXTENSION_OVERRIDE
    - reinstate check for desktop GL and add check for the extension
      when creating the framebuffer

Signed-off-by: Gert Wollny <gert.wollny at collabora.com>
---
 src/mesa/state_tracker/st_extensions.c |  6 ++++++
 src/mesa/state_tracker/st_manager.c    | 13 ++++++-------
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index 798ee60875..401609d728 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -1169,6 +1169,12 @@ void st_init_extensions(struct pipe_screen *screen,
                                      void_formats, 32,
                                      PIPE_BIND_RENDER_TARGET);
 
+      extensions->EXT_sRGB_write_control =
+         screen->is_format_supported(screen, PIPE_FORMAT_R8G8B8A8_SRGB,
+                                     PIPE_TEXTURE_2D, 0, 0,
+                                     (PIPE_BIND_DISPLAY_TARGET |
+                                      PIPE_BIND_RENDER_TARGET));
+
       if (extensions->AMD_framebuffer_multisample_advanced) {
          /* AMD_framebuffer_multisample_advanced */
          /* This can be greater than storage samples. */
diff --git a/src/mesa/state_tracker/st_manager.c b/src/mesa/state_tracker/st_manager.c
index ceb48dd490..fa12578031 100644
--- a/src/mesa/state_tracker/st_manager.c
+++ b/src/mesa/state_tracker/st_manager.c
@@ -457,14 +457,13 @@ st_framebuffer_create(struct st_context *st,
     * format such that util_format_srgb(visual->color_format) can be supported
     * by the pipe driver.  We still need to advertise the capability here.
     *
-    * For GLES, however, sRGB framebuffer write is controlled only by the
-    * capability of the framebuffer.  There is GL_EXT_sRGB_write_control to
-    * give applications the control back, but sRGB write is still enabled by
-    * default.  To avoid unexpected results, we should not advertise the
-    * capability.  This could change when we add support for
-    * EGL_KHR_gl_colorspace.
+    * For GLES sRGB framebuffer write is initially only controlled by the 
+    * framebuffer capability, with GL_EXT_sRGB_write_control control is given 
+    * back to the applications, but sRGB write is still enabled by default.
     */
-   if (_mesa_is_desktop_gl(st->ctx)) {
+   if (_mesa_is_desktop_gl(st->ctx) ||
+       st->ctx->Extensions.EXT_sRGB_write_control)
+   {
       struct pipe_screen *screen = st->pipe->screen;
       const enum pipe_format srgb_format =
          util_format_srgb(stfbi->visual->color_format);
-- 
2.18.1