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);
This commit is contained in:
Sam Lantinga 2017-08-14 05:51:44 -07:00
parent f8e1874d01
commit c59d9923b3
16 changed files with 718 additions and 778 deletions

View file

@ -47,11 +47,68 @@ typedef enum
SDL_BLENDMODE_ADD = 0x00000002, /**< additive blending
dstRGB = (srcRGB * srcA) + dstRGB
dstA = dstA */
SDL_BLENDMODE_MOD = 0x00000004 /**< color modulate
SDL_BLENDMODE_MOD = 0x00000004, /**< color modulate
dstRGB = srcRGB * dstRGB
dstA = dstA */
SDL_BLENDMODE_INVALID = 0x7FFFFFFF
/* Additional custom blend modes can be returned by SDL_ComposeCustomBlendMode() */
} SDL_BlendMode;
/**
* \brief The blend operation used when combining source and destination pixel components
*/
typedef enum
{
SDL_BLENDOPERATION_ADD = 0x1, /**< dst + src: supported by all renderers */
SDL_BLENDOPERATION_SUBTRACT = 0x2, /**< dst - src : supported by D3D9, D3D11, OpenGL, OpenGLES */
SDL_BLENDOPERATION_REV_SUBTRACT = 0x3, /**< src - dst : supported by D3D9, D3D11, OpenGL, OpenGLES */
SDL_BLENDOPERATION_MINIMUM = 0x4, /**< min(dst, src) : supported by D3D11 */
SDL_BLENDOPERATION_MAXIMUM = 0x5, /**< max(dst, src) : supported by D3D11 */
} SDL_BlendOperation;
/**
* \brief The normalized factor used to multiply pixel components
*/
typedef enum
{
SDL_BLENDFACTOR_ZERO = 0x1, /**< 0, 0, 0, 0 */
SDL_BLENDFACTOR_ONE = 0x2, /**< 1, 1, 1, 1 */
SDL_BLENDFACTOR_SRC_COLOR = 0x3, /**< srcR, srcG, srcB, srcA */
SDL_BLENDFACTOR_ONE_MINUS_SRC_COLOR = 0x4, /**< 1-srcR, 1-srcG, 1-srcB, 1-srcA */
SDL_BLENDFACTOR_SRC_ALPHA = 0x5, /**< srcA, srcA, srcA, srcA */
SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA = 0x6, /**< 1-srcA, 1-srcA, 1-srcA, 1-srcA */
SDL_BLENDFACTOR_DST_COLOR = 0x7, /**< dstR, dstG, dstB, dstA */
SDL_BLENDFACTOR_ONE_MINUS_DST_COLOR = 0x8, /**< 1-dstR, 1-dstG, 1-dstB, 1-dstA */
SDL_BLENDFACTOR_DST_ALPHA = 0x9, /**< dstA, dstA, dstA, dstA */
SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA = 0xA, /**< 1-dstA, 1-dstA, 1-dstA, 1-dstA */
} SDL_BlendFactor;
/**
* \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
*
* The result of the blend mode operation will be:
* dstRGB = dstRGB * dstColorFactor colorOperation srcRGB * srcColorFactor
* and
* dstA = dstA * dstAlphaFactor alphaOperation srcA * srcAlphaFactor
*/
extern DECLSPEC SDL_BlendMode SDLCALL SDL_ComposeCustomBlendMode(SDL_BlendFactor srcColorFactor,
SDL_BlendFactor dstColorFactor,
SDL_BlendOperation colorOperation,
SDL_BlendFactor srcAlphaFactor,
SDL_BlendFactor dstAlphaFactor,
SDL_BlendOperation alphaOperation);
/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}