cogl: Revert swizzling for BGRA buffers

As it was originally reported on
https://bugzilla.gnome.org/show_bug.cgi?id=779234#c0, the hottest path was
convert_ubyte() in mesa. Reverting this shows no trace of those hot paths,
nor any higher than usual CPU activity.

As the improvements at the time were real, I can only conclude that pixel
conversion was happening somewhere further the pipeline, and swizzling just
helped indirectly. That got eventually fixed, so swizzling just stayed to
cause grief. And lots it caused.

Time to bin this, it seems.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/486

10 files changed, 26 insertions, 97 deletions

diff --git a/cogl/cogl/cogl-driver.h b/cogl/cogl/cogl-driver.h
index 0e2d8ca79..86682d8a7 100644
--- a/cogl/cogl/cogl-driver.h
+++ b/cogl/cogl/cogl-driver.h
@@ -55,13 +55,6 @@ struct _CoglDriverVtable
                           GLenum *out_glintformat,
                           GLenum *out_glformat,
                           GLenum *out_gltype);
-  CoglPixelFormat
-  (* pixel_format_to_gl_with_target) (CoglContext *context,
-                                      CoglPixelFormat format,
-                                      CoglPixelFormat target_format,
-                                      GLenum *out_glintformat,
-                                      GLenum *out_glformat,
-                                      GLenum *out_gltype);
 
   gboolean
   (* update_features) (CoglContext *context,
diff --git a/cogl/cogl/cogl-texture-driver.h b/cogl/cogl/cogl-texture-driver.h
index ee98c22ed..f77c54880 100644
--- a/cogl/cogl/cogl-texture-driver.h
+++ b/cogl/cogl/cogl-texture-driver.h
@@ -198,7 +198,6 @@ struct _CoglTextureDriver
   CoglPixelFormat
   (* find_best_gl_get_data_format) (CoglContext     *context,
                                     CoglPixelFormat format,
-                                    CoglPixelFormat target_format,
                                     GLenum *closest_gl_format,
                                     GLenum *closest_gl_type);
 };
diff --git a/cogl/cogl/cogl-texture.c b/cogl/cogl/cogl-texture.c
index 52165ab65..695b9bea4 100644
--- a/cogl/cogl/cogl-texture.c
+++ b/cogl/cogl/cogl-texture.c
@@ -787,7 +787,6 @@ cogl_texture_get_data (CoglTexture *texture,
 
   closest_format =
     ctx->texture_driver->find_best_gl_get_data_format (ctx,
-                                                       texture_format,
                                                        format,
                                                        &closest_gl_format,
                                                        &closest_gl_type);
diff --git a/cogl/cogl/driver/gl/cogl-framebuffer-gl.c b/cogl/cogl/driver/gl/cogl-framebuffer-gl.c
index c2bf92882..5402a7075 100644
--- a/cogl/cogl/driver/gl/cogl-framebuffer-gl.c
+++ b/cogl/cogl/driver/gl/cogl-framebuffer-gl.c
@@ -1274,15 +1274,11 @@ _cogl_framebuffer_gl_read_pixels_into_bitmap (CoglFramebuffer *framebuffer,
   if (!cogl_is_offscreen (framebuffer))
     y = framebuffer_height - y - height;
 
-  /* Use target format ANY, because GL texture_swizzle extension cannot
-   * ever apply for glReadPixels.
-   */
-  required_format = ctx->driver_vtable->pixel_format_to_gl_with_target (ctx,
-                                                                        format,
-                                                                        COGL_PIXEL_FORMAT_ANY,
-                                                                        &gl_intformat,
-                                                                        &gl_format,
-                                                                        &gl_type);
+  required_format = ctx->driver_vtable->pixel_format_to_gl (ctx,
+                                                            format,
+                                                            &gl_intformat,
+                                                            &gl_format,
+                                                            &gl_type);
 
   /* NB: All offscreen rendering is done upside down so there is no need
    * to flip in this case... */
diff --git a/cogl/cogl/driver/gl/cogl-texture-2d-gl.c b/cogl/cogl/driver/gl/cogl-texture-2d-gl.c
index 6692c9403..e36c3523e 100644
--- a/cogl/cogl/driver/gl/cogl-texture-2d-gl.c
+++ b/cogl/cogl/driver/gl/cogl-texture-2d-gl.c
@@ -781,12 +781,11 @@ _cogl_texture_2d_gl_copy_from_bitmap (CoglTexture2D *tex_2d,
 
   upload_format = cogl_bitmap_get_format (upload_bmp);
 
-  ctx->driver_vtable->pixel_format_to_gl_with_target (ctx,
-                                                      upload_format,
-                                                      _cogl_texture_get_format (tex),
-                                                      NULL, /* internal gl format */
-                                                      &gl_format,
-                                                      &gl_type);
+  ctx->driver_vtable->pixel_format_to_gl (ctx,
+                                          upload_format,
+                                          NULL, /* internal gl format */
+                                          &gl_format,
+                                          &gl_type);
 
   /* If this touches the first pixel then we'll update our copy */
   if (dst_x == 0 && dst_y == 0 &&
diff --git a/cogl/cogl/driver/gl/gl/cogl-driver-gl.c b/cogl/cogl/driver/gl/gl/cogl-driver-gl.c
index 84252e169..4d46844d5 100644
--- a/cogl/cogl/driver/gl/gl/cogl-driver-gl.c
+++ b/cogl/cogl/driver/gl/gl/cogl-driver-gl.c
@@ -94,12 +94,11 @@ _cogl_driver_pixel_format_from_gl_internal (CoglContext *context,
 }
 
 static CoglPixelFormat
-_cogl_driver_pixel_format_to_gl_with_target (CoglContext *context,
-                                             CoglPixelFormat format,
-                                             CoglPixelFormat target_format,
-                                             GLenum *out_glintformat,
-                                             GLenum *out_glformat,
-                                             GLenum *out_gltype)
+_cogl_driver_pixel_format_to_gl (CoglContext     *context,
+                                 CoglPixelFormat  format,
+                                 GLenum          *out_glintformat,
+                                 GLenum          *out_glformat,
+                                 GLenum          *out_gltype)
 {
   CoglPixelFormat required_format;
   GLenum glintformat = 0;
@@ -173,16 +172,7 @@ _cogl_driver_pixel_format_to_gl_with_target (CoglContext *context,
     case COGL_PIXEL_FORMAT_BGRA_8888:
     case COGL_PIXEL_FORMAT_BGRA_8888_PRE:
       glintformat = GL_RGBA;
-      /* If the driver has texture_swizzle, pretend internal
-       * and buffer format are the same here, the pixels
-       * will be flipped through this extension.
-       */
-      if (target_format == format &&
-          _cogl_has_private_feature
-          (context, COGL_PRIVATE_FEATURE_TEXTURE_SWIZZLE))
-        glformat = GL_RGBA;
-      else
-        glformat = GL_BGRA;
+      glformat = GL_BGRA;
       gltype = GL_UNSIGNED_BYTE;
       break;
 
@@ -297,20 +287,6 @@ _cogl_driver_pixel_format_to_gl_with_target (CoglContext *context,
   return required_format;
 }
 
-static CoglPixelFormat
-_cogl_driver_pixel_format_to_gl (CoglContext *context,
-                                 CoglPixelFormat  format,
-                                 GLenum *out_glintformat,
-                                 GLenum *out_glformat,
-                                 GLenum *out_gltype)
-{
-  return _cogl_driver_pixel_format_to_gl_with_target (context,
-                                                      format, format,
-                                                      out_glintformat,
-                                                      out_glformat,
-                                                      out_gltype);
-}
-
 static gboolean
 _cogl_get_gl_version (CoglContext *ctx,
                       int *major_out,
@@ -685,7 +661,6 @@ _cogl_driver_gl =
   {
     _cogl_driver_pixel_format_from_gl_internal,
     _cogl_driver_pixel_format_to_gl,
-    _cogl_driver_pixel_format_to_gl_with_target,
     _cogl_driver_update_features,
     _cogl_offscreen_gl_allocate,
     _cogl_offscreen_gl_free,
diff --git a/cogl/cogl/driver/gl/gl/cogl-texture-driver-gl.c b/cogl/cogl/driver/gl/gl/cogl-texture-driver-gl.c
index 96d6a6da3..fbb55def5 100644
--- a/cogl/cogl/driver/gl/gl/cogl-texture-driver-gl.c
+++ b/cogl/cogl/driver/gl/gl/cogl-texture-driver-gl.c
@@ -112,18 +112,6 @@ _cogl_texture_driver_gen (CoglContext *ctx,
                                  red_swizzle) );
     }
 
-  /* If swizzle extension is available, prefer it to flip bgra buffers to rgba */
-  if ((internal_format == COGL_PIXEL_FORMAT_BGRA_8888 ||
-       internal_format == COGL_PIXEL_FORMAT_BGRA_8888_PRE) &&
-      _cogl_has_private_feature (ctx, COGL_PRIVATE_FEATURE_TEXTURE_SWIZZLE))
-    {
-      static const GLint bgra_swizzle[] = { GL_BLUE, GL_GREEN, GL_RED, GL_ALPHA };
-
-      GE( ctx, glTexParameteriv (gl_target,
-                                 GL_TEXTURE_SWIZZLE_RGBA,
-                                 bgra_swizzle) );
-    }
-
   return tex;
 }
 
@@ -531,16 +519,14 @@ static CoglPixelFormat
 _cogl_texture_driver_find_best_gl_get_data_format
                                             (CoglContext *context,
                                              CoglPixelFormat format,
-                                             CoglPixelFormat target_format,
                                              GLenum *closest_gl_format,
                                              GLenum *closest_gl_type)
 {
-  return context->driver_vtable->pixel_format_to_gl_with_target (context,
-                                                                 format,
-                                                                 target_format,
-                                                                 NULL, /* don't need */
-                                                                 closest_gl_format,
-                                                                 closest_gl_type);
+  return context->driver_vtable->pixel_format_to_gl (context,
+                                                     format,
+                                                     NULL, /* don't need */
+                                                     closest_gl_format,
+                                                     closest_gl_type);
 }
 
 const CoglTextureDriver
diff --git a/cogl/cogl/driver/gl/gles/cogl-driver-gles.c b/cogl/cogl/driver/gl/gles/cogl-driver-gles.c
index 2e75345b1..6f2cf6e59 100644
--- a/cogl/cogl/driver/gl/gles/cogl-driver-gles.c
+++ b/cogl/cogl/driver/gl/gles/cogl-driver-gles.c
@@ -65,12 +65,11 @@ _cogl_driver_pixel_format_from_gl_internal (CoglContext *context,
 }
 
 static CoglPixelFormat
-_cogl_driver_pixel_format_to_gl_with_target (CoglContext *context,
-                                             CoglPixelFormat format,
-                                             CoglPixelFormat target_format,
-                                             GLenum *out_glintformat,
-                                             GLenum *out_glformat,
-                                             GLenum *out_gltype)
+_cogl_driver_pixel_format_to_gl (CoglContext     *context,
+                                 CoglPixelFormat  format,
+                                 GLenum          *out_glintformat,
+                                 GLenum          *out_glformat,
+                                 GLenum          *out_gltype)
 {
   CoglPixelFormat required_format;
   GLenum glintformat;
@@ -218,20 +217,6 @@ _cogl_driver_pixel_format_to_gl_with_target (CoglContext *context,
   return required_format;
 }
 
-static CoglPixelFormat
-_cogl_driver_pixel_format_to_gl (CoglContext *context,
-                                 CoglPixelFormat  format,
-                                 GLenum *out_glintformat,
-                                 GLenum *out_glformat,
-                                 GLenum *out_gltype)
-{
-  return _cogl_driver_pixel_format_to_gl_with_target (context,
-                                                      format, format,
-                                                      out_glintformat,
-                                                      out_glformat,
-                                                      out_gltype);
-}
-
 static gboolean
 _cogl_get_gl_version (CoglContext *ctx,
                       int *major_out,
@@ -449,7 +434,6 @@ _cogl_driver_gles =
   {
     _cogl_driver_pixel_format_from_gl_internal,
     _cogl_driver_pixel_format_to_gl,
-    _cogl_driver_pixel_format_to_gl_with_target,
     _cogl_driver_update_features,
     _cogl_offscreen_gl_allocate,
     _cogl_offscreen_gl_free,
diff --git a/cogl/cogl/driver/gl/gles/cogl-texture-driver-gles.c b/cogl/cogl/driver/gl/gles/cogl-texture-driver-gles.c
index 9ecfd2b4c..17f529e32 100644
--- a/cogl/cogl/driver/gl/gles/cogl-texture-driver-gles.c
+++ b/cogl/cogl/driver/gl/gles/cogl-texture-driver-gles.c
@@ -613,7 +613,6 @@ static CoglPixelFormat
 _cogl_texture_driver_find_best_gl_get_data_format
                                             (CoglContext *context,
                                              CoglPixelFormat format,
-                                             CoglPixelFormat target_format,
                                              GLenum *closest_gl_format,
                                              GLenum *closest_gl_type)
 {
diff --git a/cogl/cogl/driver/nop/cogl-driver-nop.c b/cogl/cogl/driver/nop/cogl-driver-nop.c
index bedad2b13..b41a2bcc5 100644
--- a/cogl/cogl/driver/nop/cogl-driver-nop.c
+++ b/cogl/cogl/driver/nop/cogl-driver-nop.c
@@ -59,7 +59,6 @@ _cogl_driver_nop =
   {
     NULL, /* pixel_format_from_gl_internal */
     NULL, /* pixel_format_to_gl */
-    NULL, /* pixel_format_to_gl_with_target */
     _cogl_driver_update_features,
     _cogl_offscreen_nop_allocate,
     _cogl_offscreen_nop_free,