Add gs_image_alpha_mode enum for requested alpha handling: straight,
premultiplied with SRGB conversion, and just premultiplied. Both
premultiplied settings behave the same if the image is not SRGB, linear
is assumed.
Add gs_image_file3_t to store the alpha mode.
Add srgb.h file with helper functions.
Clean up vec4.h to use helpers, and remove unused functionality.
Update FFmpeg image loader to perform premultiplication on load.
GS_RGBA, GS_BGRX, and GS_BGRA now use TYPELESS DXGI formats, so we can
alias them between UNORM and UNORM_SRGB as necessary. GS_RGBA_UNORM,
GS_BGRX_UNORM, and GS_BGRA_UNORM have been added to support straight
UNORM types, which Windows requires for sharing textures from D3D9 and
OpenGL. The D3D path aliases via views, and GL aliases via
GL_EXT_texture_sRGB_decode/GL_FRAMEBUFFER_SRGB.
A significant amount of code has changed in the D3D/GL backends, but the
concepts are simple. On the D3D side, we need separate SRVs and RTVs to
support nonlinear/linear reads and writes. On the GL side, we need to
set the proper GL parameters to emulate the same.
Add gs_enable_framebuffer_srgb/gs_framebuffer_srgb_enabled to set/get
the framebuffer as SRGB or not.
Add gs_linear_srgb_active/gs_set_linear_srgb to instruct sources that
they should render as SRGB. Legacy sources can ignore this setting
without regression.
Update obs_source_draw to use linear SRGB as needed.
Update render_filter_tex to use linear SRGB as needed.
Add gs_effect_set_texture_srgb next to gs_effect_set_texture to set
texture with SRGB view instead.
Add SRGB helpers for vec4 struct.
Create GDI-compatible textures without SRGB support. Doesn't seem to
work with SRGB formats.
sse-intrin.h is a required header now, but the implicit path
breaks building addons once the headers are installed.
Fix this by making the path explicit.
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.
