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11 Commits

Author SHA1 Message Date
Sam Lantinga a8780c6a28 Updated copyright date for 2020 2020-01-16 20:49:25 -08:00
Sam Lantinga 981e0d367c Fixed bug 4903 - Lack of color multiply with alpha (SDL_BLENDMODE_MOD + SDL_BLENDMODE_BLEND) blending mode for all renderers 
Konrad

This kind of blending is rather quite useful and in my opinion should be available for all renderers. I do need it myself, but since I didn't want to use a custom blending mode which is supported only by certain renderers (e.g. not in software which is quite important for me) I did write implementation of SDL_BLENDMODE_MUL for all renderers altogether.

SDL_BLENDMODE_MUL implements following equation:

dstRGB = (srcRGB * dstRGB) + (dstRGB * (1-srcA))
dstA = (srcA * dstA) + (dstA * (1-srcA))

Background:

https://i.imgur.com/UsYhydP.png

Blended texture:

https://i.imgur.com/0juXQcV.png

Result for SDL_BLENDMODE_MOD:

https://i.imgur.com/wgNSgUl.png

Result for SDL_BLENDMODE_MUL:

https://i.imgur.com/Veokzim.png

I think I did cover all possibilities within included patch, but I didn't write any tests for SDL_BLENDMODE_MUL, so it would be lovely if someone could do it.
 2020-01-16 08:52:59 -08:00
Sam Lantinga 5e13087b0f Updated copyright for 2019 2019-01-04 22:01:14 -08:00
Ryan C. Gordon 1e4acca851 Added some detail to a Doxygen comment (thanks, Sylvain!). 2018-12-01 12:17:34 -05:00
Sam Lantinga e3cc5b2c6b Updated copyright for 2018 2018-01-03 10:03:25 -08:00
Sam Lantinga 2bf7bf2cbf Fixed compiler warning with enum 2017-08-14 10:14:07 -07:00
Sam Lantinga c59d9923b3 Implemented more flexible blending modes for accelerated renderers 
This fixes bug 2594 - Propose new blend mode, SDL_BLENDMODE_BLEND_DSTA

	blendMode = SDL_ComposeCustomBlendMode(SDL_BLENDFACTOR_SRC_ALPHA,
	                                       SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
	                                       SDL_BLENDOPERATION_ADD,
	                                       SDL_BLENDFACTOR_ZERO,
	                                       SDL_BLENDFACTOR_ONE,
	                                       SDL_BLENDOPERATION_ADD);

This fixes bug 2828 - Subtractive Blending

	blendMode = SDL_ComposeCustomBlendMode(SDL_BLENDFACTOR_SRC_ALPHA,
	                                       SDL_BLENDFACTOR_ONE,
	                                       SDL_BLENDOPERATION_SUBTRACT,
	                                       SDL_BLENDFACTOR_ZERO,
	                                       SDL_BLENDFACTOR_ONE,
	                                       SDL_BLENDOPERATION_SUBTRACT);


This goes partway to fixing bug 3684 - Add support for a pre-multiplied alpha blending mode

	blendMode = SDL_ComposeCustomBlendMode(SDL_BLENDFACTOR_ONE,
	                                       SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
	                                       SDL_BLENDOPERATION_ADD,
	                                       SDL_BLENDFACTOR_ONE,
	                                       SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
	                                       SDL_BLENDOPERATION_ADD);
 2017-08-14 05:51:44 -07:00
Sam Lantinga 45b774e3f7 Updated copyright for 2017 2017-01-01 18:33:28 -08:00
Sam Lantinga 3615633571 Renaming of guard header names to quiet -Wreserved-id-macro 
Patch contributed by Sylvain
 2016-11-20 21:34:54 -08:00
Sam Lantinga 42065e785d Updated copyright to 2016 2016-01-02 10:10:34 -08:00
Philipp Wiesemann 0e45984fa0 Fixed crash if initialization of EGL failed but was tried again later. 
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
 2015-06-21 17:33:46 +02:00