Update SDL2 to 2.0.14

code/SDL2/include/SDL_blendmode.h

@@ -1,6 +1,6 @@
 /*
   Simple DirectMedia Layer
-  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
+  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
 
   This software is provided 'as-is', without any express or implied
   warranty.  In no event will the authors be held liable for any damages
@@ -50,6 +50,9 @@ typedef enum
     SDL_BLENDMODE_MOD = 0x00000004,      /**< color modulate
                                               dstRGB = srcRGB * dstRGB
                                               dstA = dstA */
+    SDL_BLENDMODE_MUL = 0x00000008,      /**< color multiply
+                                              dstRGB = (srcRGB * dstRGB) + (dstRGB * (1-srcA))
+                                              dstA = (srcA * dstA) + (dstA * (1-srcA)) */
     SDL_BLENDMODE_INVALID = 0x7FFFFFFF
 
     /* Additional custom blend modes can be returned by SDL_ComposeCustomBlendMode() */
@@ -90,12 +93,12 @@ typedef enum
 /**
  *  \brief Create a custom blend mode, which may or may not be supported by a given renderer
  *
- *  \param srcColorFactor
- *  \param dstColorFactor
- *  \param colorOperation
- *  \param srcAlphaFactor
- *  \param dstAlphaFactor
- *  \param alphaOperation
+ *  \param srcColorFactor source color factor
+ *  \param dstColorFactor destination color factor
+ *  \param colorOperation color operation
+ *  \param srcAlphaFactor source alpha factor
+ *  \param dstAlphaFactor destination alpha factor
+ *  \param alphaOperation alpha operation
  *
  *  The result of the blend mode operation will be:
  *      dstRGB = dstRGB * dstColorFactor colorOperation srcRGB * srcColorFactor