Commit c59d9923b3a3022e15df15130bf781adc442f220

Sam Lantinga 2017-08-14T05:51:44

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);