[Mesa-dev] [RFC PATCH 5/8] mesa/st: rework support for sRGB framebuffer attachements
Gert Wollny
gw.fossdev at gmail.com
Tue Nov 13 17:27:45 UTC 2018
From: Gert Wollny <gert.wollny at collabora.com>
For GLES sRGB framebuffer attachemnt support is provided in two steps:
sRGB attachments like described in EXT_sRGB and GLES 3.0 that enable
linear to sRGB color space transformation automatically, and sRGB write
control that brings GLES on par with EXT_framebuffer_sRGB. Set the
according flags to reflect these two parts.
As a difference between desktopm GL and GLES, on desktop GL for a sRGB
framebuffer attachment the linear-sRGB conversion is turned off by default,
and for GLES it is turned on. This needs to be taken into account when
creating framebuffer attachemnts.
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
v3: - Only create sRGB renderbuffers based on Visual.srgbCapable when
on desktop GL.
v4: - Use PIPE_FORMAT_B8G8R8A8_SRGB to check for the capability, since this
is also the format that is used top check for EGL_KHR_gl_colorspace
support. virgl on a GLES host usually doesn't provide this format but
one can make it available to signal that the host supports this
extension.
v5: - drop check for PIPE_FORMAT_B8G8R8A8_SRGB in favour of using the new
PIPE_CAP_SRGB_WRITE_CONTROL cap flag.
- enable EXT_sRGB based on the sRGB formats supported and
EXT_framebuffer_sRGB by checking for PIPE_CAP_SRGB_WRITE_CONTROL.
Signed-off-by: Gert Wollny <gert.wollny at collabora.com>
---
src/mesa/state_tracker/st_cb_fbo.c | 4 +--
src/mesa/state_tracker/st_extensions.c | 6 ++++-
src/mesa/state_tracker/st_format.c | 2 +-
src/mesa/state_tracker/st_manager.c | 37 ++++++++++++++++----------
4 files changed, 31 insertions(+), 18 deletions(-)
diff --git a/src/mesa/state_tracker/st_cb_fbo.c b/src/mesa/state_tracker/st_cb_fbo.c
index 0e535257cb..49a989f126 100644
--- a/src/mesa/state_tracker/st_cb_fbo.c
+++ b/src/mesa/state_tracker/st_cb_fbo.c
@@ -139,7 +139,7 @@ st_renderbuffer_alloc_storage(struct gl_context * ctx,
/* If an sRGB framebuffer is unsupported, sRGB formats behave like linear
* formats.
*/
- if (!ctx->Extensions.EXT_framebuffer_sRGB) {
+ if (!ctx->Extensions.EXT_sRGB) {
internalFormat = _mesa_get_linear_internalformat(internalFormat);
}
@@ -656,7 +656,7 @@ st_validate_attachment(struct gl_context *ctx,
/* If the encoding is sRGB and sRGB rendering cannot be enabled,
* check for linear format support instead.
* Later when we create a surface, we change the format to a linear one. */
- if (!ctx->Extensions.EXT_framebuffer_sRGB &&
+ if (!ctx->Extensions.EXT_sRGB &&
_mesa_get_format_color_encoding(texFormat) == GL_SRGB) {
const mesa_format linearFormat = _mesa_get_srgb_format_linear(texFormat);
format = st_mesa_format_to_pipe_format(st_context(ctx), linearFormat);
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index 16889074f6..9e63e7b74c 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -786,7 +786,7 @@ void st_init_extensions(struct pipe_screen *screen,
PIPE_FORMAT_B10G10R10A2_UINT },
GL_TRUE }, /* at least one format must be supported */
- { { o(EXT_framebuffer_sRGB) },
+ { { o(EXT_sRGB) },
{ PIPE_FORMAT_A8B8G8R8_SRGB,
PIPE_FORMAT_B8G8R8A8_SRGB,
PIPE_FORMAT_R8G8B8A8_SRGB },
@@ -1316,6 +1316,10 @@ void st_init_extensions(struct pipe_screen *screen,
extensions->ARB_texture_buffer_object_rgb32 &&
extensions->ARB_shader_image_load_store;
+ extensions->EXT_framebuffer_sRGB =
+ screen->get_param(screen, PIPE_CAP_SRGB_WRITE_CONTROL) &&
+ extensions->EXT_sRGB;
+
/* Unpacking a varying in the fragment shader costs 1 texture indirection.
* If the number of available texture indirections is very limited, then we
* prefer to disable varying packing rather than run the risk of varying
diff --git a/src/mesa/state_tracker/st_format.c b/src/mesa/state_tracker/st_format.c
index caddd76c5d..aacb878828 100644
--- a/src/mesa/state_tracker/st_format.c
+++ b/src/mesa/state_tracker/st_format.c
@@ -2457,7 +2457,7 @@ st_QuerySamplesForFormat(struct gl_context *ctx, GLenum target,
/* If an sRGB framebuffer is unsupported, sRGB formats behave like linear
* formats.
*/
- if (!ctx->Extensions.EXT_framebuffer_sRGB) {
+ if (!ctx->Extensions.EXT_sRGB) {
internalFormat = _mesa_get_linear_internalformat(internalFormat);
}
diff --git a/src/mesa/state_tracker/st_manager.c b/src/mesa/state_tracker/st_manager.c
index 076ad42646..25e2dcad4c 100644
--- a/src/mesa/state_tracker/st_manager.c
+++ b/src/mesa/state_tracker/st_manager.c
@@ -295,7 +295,7 @@ st_framebuffer_update_attachments(struct st_framebuffer *stfb)
*/
static boolean
st_framebuffer_add_renderbuffer(struct st_framebuffer *stfb,
- gl_buffer_index idx)
+ gl_buffer_index idx, bool prefer_srgb)
{
struct gl_renderbuffer *rb;
enum pipe_format format;
@@ -318,7 +318,7 @@ st_framebuffer_add_renderbuffer(struct st_framebuffer *stfb,
break;
default:
format = stfb->iface->visual->color_format;
- if (stfb->Base.Visual.sRGBCapable)
+ if (prefer_srgb)
format = util_format_srgb(format);
sw = FALSE;
break;
@@ -436,6 +436,7 @@ st_framebuffer_create(struct st_context *st,
struct st_framebuffer *stfb;
struct gl_config mode;
gl_buffer_index idx;
+ bool prefer_srgb = false;
if (!stfbi)
return NULL;
@@ -457,14 +458,15 @@ 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, however, sRGB framebuffer write is initially only controlled
+ * by the capability of the framebuffer, with GL_EXT_sRGB_write_control
+ * control is given back to the applications, but GL_FRAMEBUFFER_SRGB is
+ * still enabled by default since this is the behaviour when
+ * EXT_sRGB_write_control is not available. Since GL_EXT_sRGB_write_control
+ * brings GLES on par with desktop GLs EXT_framebuffer_sRGB, the same
+ * extension flag is used to check for the capability.
*/
- if (_mesa_is_desktop_gl(st->ctx)) {
+ if (st->ctx->Extensions.EXT_framebuffer_sRGB) {
struct pipe_screen *screen = st->pipe->screen;
const enum pipe_format srgb_format =
util_format_srgb(stfbi->visual->color_format);
@@ -475,8 +477,14 @@ st_framebuffer_create(struct st_context *st,
PIPE_TEXTURE_2D, stfbi->visual->samples,
stfbi->visual->samples,
(PIPE_BIND_DISPLAY_TARGET |
- PIPE_BIND_RENDER_TARGET)))
+ PIPE_BIND_RENDER_TARGET))) {
mode.sRGBCapable = GL_TRUE;
+ /* Since GL_FRAMEBUFFER_SRGB is enabled by default on GLES we must not
+ * create renderbuffers with an sRGB format derived from the
+ * visual->color_format, but we still want sRGB for desktop GL.
+ */
+ prefer_srgb = _mesa_is_desktop_gl(st->ctx);
+ }
}
_mesa_initialize_window_framebuffer(&stfb->Base, &mode);
@@ -487,13 +495,13 @@ st_framebuffer_create(struct st_context *st,
/* add the color buffer */
idx = stfb->Base._ColorDrawBufferIndexes[0];
- if (!st_framebuffer_add_renderbuffer(stfb, idx)) {
+ if (!st_framebuffer_add_renderbuffer(stfb, idx, prefer_srgb)) {
free(stfb);
return NULL;
}
- st_framebuffer_add_renderbuffer(stfb, BUFFER_DEPTH);
- st_framebuffer_add_renderbuffer(stfb, BUFFER_ACCUM);
+ st_framebuffer_add_renderbuffer(stfb, BUFFER_DEPTH, false);
+ st_framebuffer_add_renderbuffer(stfb, BUFFER_ACCUM, false);
stfb->stamp = 0;
st_framebuffer_update_attachments(stfb);
@@ -1183,7 +1191,8 @@ st_manager_add_color_renderbuffer(struct st_context *st,
return FALSE;
}
- if (!st_framebuffer_add_renderbuffer(stfb, idx))
+ if (!st_framebuffer_add_renderbuffer(stfb, idx,
+ stfb->Base.Visual.sRGBCapable))
return FALSE;
st_framebuffer_update_attachments(stfb);
--
2.18.1
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