kc3-lang/SDL/src

Branch : - branch - v2.28 - tag -

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• Author : Sam Lantinga
  Date : 2013-08-16 06:59:19
  Hash : 89bc80f1
  Message : Fixed alpha blending for the MMX blit functions I see the Remarks of function SDL_BlitSurface shows that "when SDL_BLENDMODE_BLEND, we have dstA = srcA + (dstA * (1-srcA))". however, I tested some pictures but the result implies "dstA=arcA" actually. I stepped into the source code, and found after I set SDL_BLENDMODE_BLEND for the source surface, the final blit function is BlitRGBtoRGBPixelAlphaMMX when I use SDL_BlitSurface on my computer. And I found these codes: else if (alpha == amask) { /* opaque alpha -- copy RGB, keep dst alpha */ *dstp = (*srcp & chanmask) | (*dstp & ~chanmask); The same code is used in BlitRGBtoRGBPixelAlphaMMX3DNOW and BlitRGBtoRGBPixelAlpha. So I think they still keep dst alpha. Best regards, Jianyu Guan

• Files
• SDL.c
• SDL_assert.c
• SDL_assert_c.h
• SDL_error.c
• SDL_error_c.h
• SDL_hints.c
• SDL_log.c
• atomic
• audio
• core
• cpuinfo
• events
• file
• haptic
• joystick
• libm
• loadso
• main
• power
• render
• stdlib
• test
• thread
• timer
• video