The blend operation used when combining source and destination pixel components
Defined in SDL_blendmode.h
typedef enum SDL_BlendOperation
{0x1, /**< dst + src: supported by all renderers */
SDL_BLENDOPERATION_ADD = 0x2, /**< src - dst : supported by D3D9, D3D11, OpenGL, OpenGLES */
SDL_BLENDOPERATION_SUBTRACT = 0x3, /**< dst - src : supported by D3D9, D3D11, OpenGL, OpenGLES */
SDL_BLENDOPERATION_REV_SUBTRACT = 0x4, /**< min(dst, src) : supported by D3D9, D3D11 */
SDL_BLENDOPERATION_MINIMUM = 0x5 /**< max(dst, src) : supported by D3D9, D3D11 */
SDL_BLENDOPERATION_MAXIMUM = } SDL_BlendOperation;