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Implemented more flexible blending modes for accelerated renderers

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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
Download patch file Download diff file Expand all files Collapse all files

135
src/render/SDL_render.c
View file

@ -44,6 +44,31 @@
return retval; \
}
/* Predefined blend modes */
#define SDL_COMPOSE_BLENDMODE(srcColorFactor, dstColorFactor, colorOperation, \
srcAlphaFactor, dstAlphaFactor, alphaOperation) \
(SDL_BlendMode)(((Uint32)colorOperation << 0) | \
((Uint32)srcColorFactor << 4) | \
((Uint32)dstColorFactor << 8) | \
((Uint32)alphaOperation << 16) | \
((Uint32)srcAlphaFactor << 20) | \
((Uint32)dstAlphaFactor << 24))
#define SDL_BLENDMODE_NONE_FULL \
SDL_COMPOSE_BLENDMODE(SDL_BLENDFACTOR_ONE, SDL_BLENDFACTOR_ZERO, SDL_BLENDOPERATION_ADD, \
SDL_BLENDFACTOR_ONE, SDL_BLENDFACTOR_ZERO, SDL_BLENDOPERATION_ADD)
#define SDL_BLENDMODE_BLEND_FULL \
SDL_COMPOSE_BLENDMODE(SDL_BLENDFACTOR_SRC_ALPHA, SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA, SDL_BLENDOPERATION_ADD, \
SDL_BLENDFACTOR_ONE, SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA, SDL_BLENDOPERATION_ADD)
#define SDL_BLENDMODE_ADD_FULL \
SDL_COMPOSE_BLENDMODE(SDL_BLENDFACTOR_SRC_ALPHA, SDL_BLENDFACTOR_ONE, SDL_BLENDOPERATION_ADD, \
SDL_BLENDFACTOR_ZERO, SDL_BLENDFACTOR_ONE, SDL_BLENDOPERATION_ADD)
#define SDL_BLENDMODE_MOD_FULL \
SDL_COMPOSE_BLENDMODE(SDL_BLENDFACTOR_ZERO, SDL_BLENDFACTOR_SRC_COLOR, SDL_BLENDOPERATION_ADD, \
SDL_BLENDFACTOR_ZERO, SDL_BLENDFACTOR_ONE, SDL_BLENDOPERATION_ADD)
#if !SDL_RENDER_DISABLED
static const SDL_RenderDriver *render_drivers[] = {
@ -379,6 +404,23 @@ SDL_GetRendererOutputSize(SDL_Renderer * renderer, int *w, int *h)
}
}
static SDL_bool
IsSupportedBlendMode(SDL_Renderer * renderer, SDL_BlendMode blendMode)
{
switch (blendMode)
{
/* These are required to be supported by all renderers */
case SDL_BLENDMODE_NONE:
case SDL_BLENDMODE_BLEND:
case SDL_BLENDMODE_ADD:
case SDL_BLENDMODE_MOD:
return SDL_TRUE;
default:
return renderer->SupportsBlendMode && renderer->SupportsBlendMode(renderer, blendMode);
}
}
static SDL_bool
IsSupportedFormat(SDL_Renderer * renderer, Uint32 format)
{
@ -706,6 +748,9 @@ SDL_SetTextureBlendMode(SDL_Texture * texture, SDL_BlendMode blendMode)
CHECK_TEXTURE_MAGIC(texture, -1);
renderer = texture->renderer;
if (!IsSupportedBlendMode(renderer, blendMode)) {
return SDL_Unsupported();
}
texture->blendMode = blendMode;
if (texture->native) {
return SDL_SetTextureBlendMode(texture->native, blendMode);
@ -1452,6 +1497,9 @@ SDL_SetRenderDrawBlendMode(SDL_Renderer * renderer, SDL_BlendMode blendMode)
{
CHECK_RENDERER_MAGIC(renderer, -1);
if (!IsSupportedBlendMode(renderer, blendMode)) {
return SDL_Unsupported();
}
renderer->blendMode = blendMode;
return 0;
}
@ -2042,4 +2090,91 @@ int SDL_GL_UnbindTexture(SDL_Texture *texture)
return SDL_Unsupported();
}
static SDL_BlendMode
SDL_GetShortBlendMode(SDL_BlendMode blendMode)
{
switch (blendMode) {
case SDL_BLENDMODE_NONE_FULL:
return SDL_BLENDMODE_NONE;
case SDL_BLENDMODE_BLEND_FULL:
return SDL_BLENDMODE_BLEND;
case SDL_BLENDMODE_ADD_FULL:
return SDL_BLENDMODE_ADD;
case SDL_BLENDMODE_MOD_FULL:
return SDL_BLENDMODE_MOD;
default:
return blendMode;
}
}
static SDL_BlendMode
SDL_GetLongBlendMode(SDL_BlendMode blendMode)
{
switch (blendMode) {
case SDL_BLENDMODE_NONE:
return SDL_BLENDMODE_NONE_FULL;
case SDL_BLENDMODE_BLEND:
return SDL_BLENDMODE_BLEND_FULL;
case SDL_BLENDMODE_ADD:
return SDL_BLENDMODE_ADD_FULL;
case SDL_BLENDMODE_MOD:
return SDL_BLENDMODE_MOD_FULL;
default:
return blendMode;
}
}
SDL_BlendMode
SDL_ComposeCustomBlendMode(SDL_BlendFactor srcColorFactor, SDL_BlendFactor dstColorFactor,
SDL_BlendOperation colorOperation,
SDL_BlendFactor srcAlphaFactor, SDL_BlendFactor dstAlphaFactor,
SDL_BlendOperation alphaOperation)
{
SDL_BlendMode blendMode = SDL_COMPOSE_BLENDMODE(srcColorFactor, dstColorFactor, colorOperation,
srcAlphaFactor, dstAlphaFactor, alphaOperation);
return SDL_GetShortBlendMode(blendMode);
}
SDL_BlendFactor
SDL_GetBlendModeSrcColorFactor(SDL_BlendMode blendMode)
{
blendMode = SDL_GetLongBlendMode(blendMode);
return (SDL_BlendFactor)(((Uint32)blendMode >> 4) & 0xF);
}
SDL_BlendFactor
SDL_GetBlendModeDstColorFactor(SDL_BlendMode blendMode)
{
blendMode = SDL_GetLongBlendMode(blendMode);
return (SDL_BlendFactor)(((Uint32)blendMode >> 8) & 0xF);
}
SDL_BlendOperation
SDL_GetBlendModeColorOperation(SDL_BlendMode blendMode)
{
blendMode = SDL_GetLongBlendMode(blendMode);
return (SDL_BlendOperation)(((Uint32)blendMode >> 0) & 0xF);
}
SDL_BlendFactor
SDL_GetBlendModeSrcAlphaFactor(SDL_BlendMode blendMode)
{
blendMode = SDL_GetLongBlendMode(blendMode);
return (SDL_BlendFactor)(((Uint32)blendMode >> 20) & 0xF);
}
SDL_BlendFactor
SDL_GetBlendModeDstAlphaFactor(SDL_BlendMode blendMode)
{
blendMode = SDL_GetLongBlendMode(blendMode);
return (SDL_BlendFactor)(((Uint32)blendMode >> 24) & 0xF);
}
SDL_BlendOperation
SDL_GetBlendModeAlphaOperation(SDL_BlendMode blendMode)
{
blendMode = SDL_GetLongBlendMode(blendMode);
return (SDL_BlendFactor)(((Uint32)blendMode >> 16) & 0xF);
}
/* vi: set ts=4 sw=4 expandtab: */