Code submissions have continually suffered from formatting
inconsistencies that constantly have to be addressed. Using
clang-format simplifies this by making code formatting more consistent,
and allows automation of the code formatting so that maintainers can
focus more on the code itself instead of code formatting.
There are cases where alpha is multiplied unnecessarily. This change
attempts to use premultiplied alpha blending for composition.
To keep this change simple, The filter chain will continue to use
straight alpha. Otherwise, every source would need to modified to output
premultiplied, and every filter modified for premultiplied input.
"DrawAlphaDivide" shader techniques have been added to convert from
premultiplied alpha to straight alpha for final output. "DrawMatrix"
techniques ignore alpha, so they do not appear to need changing.
One remaining issue is that scale effects are set up here to use the
same shader logic for both scale filters (straight alpha - incorrectly),
and output composition (premultiplied alpha - correctly). A fix could be
made to add additional shaders for straight alpha, but the "real" fix
may be to eliminate the straight alpha path at some point.
For graphics, SrcBlendAlpha and DestBlendAlpha were both ONE, and could
combine together to form alpha values greater than one. This is not as
noticeable of a problem for UNORM targets because the channels are
clamped, but it will likely become a problem in more situations if FLOAT
targets are used.
This change switches DestBlendAlpha to INVSRCALPHA. The blending
behavior of stacked transparents is preserved without overflowing the
alpha channel.
obs-transitions: Use premultiplied alpha blend, and simplify shaders
because both inputs and outputs use premultiplied alpha now.
Fixes https://obsproject.com/mantis/view.php?id=1108
Add support for debug markers via D3DPERF API and KHR_debug. This makes
it easier to understand RenderDoc captures.
D3DPERF is preferred to ID3DUserDefinedAnnotation because it supports
colors. d3d9.lib is now linked in to support this.
This feature is disabled by default, and is controlled by
GS_USE_DEBUG_MARKERS.
From: obsproject/obs-studio#1799
Currently SrcBlendAlpha and DestBlendAlpha are both ONE, and can
combine together to form two. This is not a noticeable problem for
UNORM targets because the channels are clamped, but it will likely
become a problem if FLOAT targets are more widely used.
This change switches DestBlendAlpha to INVSRCALPHA, and starts
backgrounds as opaque black instead of transparent black. The blending
behavior of stacked transparents is preserved without overflowing the
alpha channel.
(Note: This commit also modifies libobs-d3d11 and libobs-opengl)
Allows the ability to flush data directly without having to use the
buffer's internal data.
Allows the caller to manage his/her own vertex/index buffer data if
desired, working around the design flaw of having to rely on a
vertex/index buffer's internal data.
Prevents from having to pass ownership of buffer data from caller when
using gs_vertexbuffer_create() or gs_indexbuffer_create() (which is a
design flaw).
Adds warnings for graphics functions to ensure that graphics functions
are called within an active graphics context, and add warnings if
required pointer parameters are null.
(Non-compiling commit: windowless-context branch)
Changes API from:
---------------------
EXPORT int gs_create(graphics_t **graphics, const char *module,
const struct gs_init_data *data);
To:
---------------------
EXPORT int gs_create(graphics_t **graphics, const char *module,
uint32_t adapter);
Summary:
---------------------
Changes the gs_create function to use an adapter parameter instead of
requiring a gs_init_data with window/color/etc information.
This allows the ability to separate the blend states of color and alpha.
The default blend state has also changed so that alpha is always added
together to ensure that the destination image always gets an alpha value
that is actually usable after the operation (for render targets).
Old default state:
color source: GS_BLEND_SRCALPHA, color dest: GS_BLEND_INVSRCALPHA
alpha source: GS_BLEND_SRCALPHA, alpha dest: GS_BLEND_INVSRCALPHA
New default state:
color source: GS_BLEND_SRCALPHA, color dest: GS_BLEND_INVSRCALPHA
alpha source: GS_BLEND_ONE, alpha dest: GS_BLEND_ONE
This is particularly important for the filter pipeline in order to
ensure that when the last filter is reached that the original blend
state is properly reset.
The gs_enum_adapters function is an optional implementation to allow
enumeration of available graphics adapters that can be used with the
program. The ID associated with the adapter can be an index or a hash
depending on the implementation.
This adds support for the windows 8+ output duplicator feature which
allows the efficient capturing of a specific monitor connected to the
currently used device.
When the image data is copied into a texture with flipping set to true
each row has to be copied into the (height - row - 1)th row instead of
the row with the same number. Otherwise it will just create an unflipped
copy.
This Fixes a minor flaw with the API where data had to always be mutable
to be usable by the API.
Functions that do not modify the fundamental underlying data of a
structure should be marked as constant, both for safety and to signify
that the parameter is input only and will not be modified by the
function using it.
Typedef pointers are unsafe. If you do:
typedef struct bla *bla_t;
then you cannot use it as a constant, such as: const bla_t, because
that constant will be to the pointer itself rather than to the
underlying data. I admit this was a fundamental mistake that must
be corrected.
All typedefs that were pointer types will now have their pointers
removed from the type itself, and the pointers will be used when they
are actually used as variables/parameters/returns instead.
This does not break ABI though, which is pretty nice.
Multiplication of the matricies was being done in the wrong direction.
This caused source transformations to come out looking incorrect, for
example the linux-xshm source's cursor would not be drawn correctly or
in the right position if the source was moved/scaled/rotated. The
problem just turned out to be that the gs_matrix_* functions were
multiplying in the wrong direction. Reverse the direction of
multiplication, and the problem is solved.
Changed API functions:
libobs: obs_reset_video
Before, video initialization returned a boolean, but "failed" is too
little information, if it fails due to lack of device capabilities or
bad video device parameters, the front-end needs to know that.
The OBS Basic UI has also been updated to reflect this API change.
I was implementing a pushing/popping attributes function like with GL,
but I realized that for our particular purposes (and actually for most
purposes) its usage was somewhat.. niche. I may still implement
pushing/popping of attributes in the future, though right now I feel
using a function to reset the state is sufficient for our purposes.
NOTE: In texture_setimage, I had to move variables to the top of the
scope because microsoft's C compiler will give the legacy C90 error of:
'illegal use of this type as an expression'.
To sum it up, microsoft's C compiler is still utter garbage.
...I'm actually concerned that I went a bit overkill trying to prevent
backwards compatibility issues with this abstraction design, because
this is a large number of files that have to be modified just to add a
single graphics subsystem export. Someone's going to strangle me, and
when you know that someone might strangle you, that means that you did
something wrong. We'll have to look in to simplifying this in the
future without killing backward compatibility safety.