From 6c6c6ad5412f5bb13592630d7cb3b7aed25d159b Mon Sep 17 00:00:00 2001

From: Pekka Paalanen <pekka.paalanen@collabora.com>

Date: Mon, 6 May 2019 14:09:16 +0300

Subject: [PATCH 04/12] cogl: Relax formats on glBlitFramebuffer

Depends on: "cogl: Replace ANGLE with GLES3 and NV framebuffer_blit"

As a possible ANGLE implementation is not longer limiting the pixel format

matching, lift the requirement of having the same pixel format.

We still cannot do a premult <-> non-premult conversion during a blit, so guard

against that.

This will be useful in follow-up work to copy from onscreen primary GPU

framebuffer to an offscreen secondary GPU framebuffer if the formats do not

match exactly.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/615

(cherry picked from commit 6df34eb4b7c65210f4066f7eb9bd462278b7279b)

---

 cogl/cogl/cogl-blit.c                | 10 ++++++----

 cogl/cogl/cogl-framebuffer-private.h |  8 ++++++--

 cogl/cogl/cogl-framebuffer.c         |  6 ++++--

 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/cogl/cogl/cogl-blit.c b/cogl/cogl/cogl-blit.c

index 74f404f3d..a61eb66d2 100644

--- a/cogl/cogl/cogl-blit.c

+++ b/cogl/cogl/cogl-blit.c

@@ -4,6 +4,7 @@

  * A Low Level GPU Graphics and Utilities API

  *

  * Copyright (C) 2011 Intel Corporation.

+ * Copyright (C) 2019 DisplayLink (UK) Ltd.

  *

  * Permission is hereby granted, free of charge, to any person

  * obtaining a copy of this software and associated documentation

@@ -152,10 +153,11 @@ _cogl_blit_framebuffer_begin (CoglBlitData *data)

   CoglFramebuffer *dst_fb, *src_fb;

   CoglError *ignore_error = NULL;

-  /* We can only blit between FBOs if both textures are the same

-     format and the blit framebuffer extension is supported */

-  if ((_cogl_texture_get_format (data->src_tex) & ~COGL_A_BIT) !=

-      (_cogl_texture_get_format (data->dst_tex) & ~COGL_A_BIT) ||

+  /* We can only blit between FBOs if both textures have the same

+     premult convention and the blit framebuffer extension is

+     supported. */

+  if ((_cogl_texture_get_format (data->src_tex) & COGL_PREMULT_BIT) !=

+      (_cogl_texture_get_format (data->dst_tex) & COGL_PREMULT_BIT) ||

       !_cogl_has_private_feature (ctx, COGL_PRIVATE_FEATURE_OFFSCREEN_BLIT))

     return FALSE;

diff --git a/cogl/cogl/cogl-framebuffer-private.h b/cogl/cogl/cogl-framebuffer-private.h

index 3aab852c4..b06fbaee1 100644

--- a/cogl/cogl/cogl-framebuffer-private.h

+++ b/cogl/cogl/cogl-framebuffer-private.h

@@ -381,8 +381,12 @@ _cogl_push_framebuffers (CoglFramebuffer *draw_buffer,

  * This blits a region of the color buffer of the source buffer

  * to the destination buffer. This function should only be

  * called if the COGL_PRIVATE_FEATURE_OFFSCREEN_BLIT feature is

- * advertised. The two buffers must both be offscreen and have the

- * same format.

+ * advertised. The two buffers must both be offscreen.

+ *

+ * The two buffers must have the same value types (e.g. floating-point,

+ * unsigned int, signed int, or fixed-point), but color formats do not

+ * need to match. This limitation comes from OpenGL ES 3.0 definition

+ * of glBlitFramebuffer.

  *

  * Note that this function differs a lot from the glBlitFramebuffer

  * function provided by the GL_EXT_framebuffer_blit extension. Notably

diff --git a/cogl/cogl/cogl-framebuffer.c b/cogl/cogl/cogl-framebuffer.c

index bd8a7fa42..0bc225945 100644

--- a/cogl/cogl/cogl-framebuffer.c

+++ b/cogl/cogl/cogl-framebuffer.c

@@ -4,6 +4,7 @@

  * A Low Level GPU Graphics and Utilities API

  *

  * Copyright (C) 2007,2008,2009,2012 Intel Corporation.

+ * Copyright (C) 2019 DisplayLink (UK) Ltd.

  *

  * Permission is hereby granted, free of charge, to any person

  * obtaining a copy of this software and associated documentation

@@ -1468,8 +1469,9 @@ _cogl_blit_framebuffer (CoglFramebuffer *src,

      support this */

   _COGL_RETURN_IF_FAIL (cogl_is_offscreen (src));

   _COGL_RETURN_IF_FAIL (cogl_is_offscreen (dest));

-  /* The buffers must be the same format */

-  _COGL_RETURN_IF_FAIL (src->internal_format == dest->internal_format);

+  /* The buffers must use the same premult convention */

+  _COGL_RETURN_IF_FAIL ((src->internal_format & COGL_PREMULT_BIT) ==

+                        (dest->internal_format & COGL_PREMULT_BIT));

   /* Make sure the current framebuffers are bound. We explicitly avoid

      flushing the clip state so we can bind our own empty state */

-- 

2.21.0