mirror of
https://github.com/libsdl-org/SDL.git
synced 2025-05-21 04:08:27 +00:00
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
parent
f8e1874d01
commit
c59d9923b3
16 changed files with 718 additions and 778 deletions
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@ -56,6 +56,7 @@ static SDL_Renderer *GLES_CreateRenderer(SDL_Window * window, Uint32 flags);
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static void GLES_WindowEvent(SDL_Renderer * renderer,
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const SDL_WindowEvent *event);
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static int GLES_GetOutputSize(SDL_Renderer * renderer, int *w, int *h);
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static SDL_bool GLES_SupportsBlendMode(SDL_Renderer * renderer, SDL_BlendMode blendMode);
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static int GLES_CreateTexture(SDL_Renderer * renderer, SDL_Texture * texture);
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static int GLES_UpdateTexture(SDL_Renderer * renderer, SDL_Texture * texture,
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const SDL_Rect * rect, const void *pixels,
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@ -116,7 +117,7 @@ typedef struct
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SDL_GLContext context;
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struct {
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Uint32 color;
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int blendMode;
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SDL_BlendMode blendMode;
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SDL_bool tex_coords;
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} current;
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@ -130,6 +131,8 @@ typedef struct
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GLuint window_framebuffer;
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SDL_bool GL_OES_blend_func_separate_supported;
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SDL_bool GL_OES_blend_equation_separate_supported;
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SDL_bool GL_OES_blend_subtract_supported;
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} GLES_RenderData;
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typedef struct
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@ -262,7 +265,7 @@ GLES_ResetState(SDL_Renderer *renderer)
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}
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data->current.color = 0xffffffff;
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data->current.blendMode = -1;
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data->current.blendMode = SDL_BLENDMODE_INVALID;
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data->current.tex_coords = SDL_FALSE;
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data->glDisable(GL_DEPTH_TEST);
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@ -319,6 +322,7 @@ GLES_CreateRenderer(SDL_Window * window, Uint32 flags)
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renderer->WindowEvent = GLES_WindowEvent;
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renderer->GetOutputSize = GLES_GetOutputSize;
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renderer->SupportsBlendMode = GLES_SupportsBlendMode;
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renderer->CreateTexture = GLES_CreateTexture;
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renderer->UpdateTexture = GLES_UpdateTexture;
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renderer->LockTexture = GLES_LockTexture;
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@ -388,6 +392,12 @@ GLES_CreateRenderer(SDL_Window * window, Uint32 flags)
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if (SDL_GL_ExtensionSupported("GL_OES_blend_func_separate")) {
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data->GL_OES_blend_func_separate_supported = SDL_TRUE;
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}
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if (SDL_GL_ExtensionSupported("GL_OES_blend_equation_separate")) {
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data->GL_OES_blend_equation_separate_supported = SDL_TRUE;
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}
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if (SDL_GL_ExtensionSupported("GL_OES_blend_subtract")) {
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data->GL_OES_blend_subtract_supported = SDL_TRUE;
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}
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/* Set up parameters for rendering */
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GLES_ResetState(renderer);
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@ -430,6 +440,79 @@ GLES_GetOutputSize(SDL_Renderer * renderer, int *w, int *h)
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return 0;
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}
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static GLenum GetBlendFunc(SDL_BlendFactor factor)
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{
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switch (factor) {
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case SDL_BLENDFACTOR_ZERO:
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return GL_ZERO;
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case SDL_BLENDFACTOR_ONE:
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return GL_ONE;
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case SDL_BLENDFACTOR_SRC_COLOR:
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return GL_SRC_COLOR;
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case SDL_BLENDFACTOR_ONE_MINUS_SRC_COLOR:
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return GL_ONE_MINUS_SRC_COLOR;
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case SDL_BLENDFACTOR_SRC_ALPHA:
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return GL_SRC_ALPHA;
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case SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA:
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return GL_ONE_MINUS_SRC_ALPHA;
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case SDL_BLENDFACTOR_DST_COLOR:
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return GL_DST_COLOR;
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case SDL_BLENDFACTOR_ONE_MINUS_DST_COLOR:
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return GL_ONE_MINUS_DST_COLOR;
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case SDL_BLENDFACTOR_DST_ALPHA:
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return GL_DST_ALPHA;
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case SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA:
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return GL_ONE_MINUS_DST_ALPHA;
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default:
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return GL_INVALID_ENUM;
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}
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}
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static GLenum GetBlendEquation(SDL_BlendOperation operation)
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{
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switch (operation) {
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case SDL_BLENDOPERATION_ADD:
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return GL_FUNC_ADD_OES;
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case SDL_BLENDOPERATION_SUBTRACT:
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return GL_FUNC_SUBTRACT_OES;
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case SDL_BLENDOPERATION_REV_SUBTRACT:
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return GL_FUNC_REVERSE_SUBTRACT_OES;
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default:
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return GL_INVALID_ENUM;
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}
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}
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static SDL_bool
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GLES_SupportsBlendMode(SDL_Renderer * renderer, SDL_BlendMode blendMode)
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{
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GLES_RenderData *data = (GLES_RenderData *) renderer->driverdata;
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SDL_BlendFactor srcColorFactor = SDL_GetBlendModeSrcColorFactor(blendMode);
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SDL_BlendFactor srcAlphaFactor = SDL_GetBlendModeSrcAlphaFactor(blendMode);
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SDL_BlendOperation colorOperation = SDL_GetBlendModeColorOperation(blendMode);
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SDL_BlendFactor dstColorFactor = SDL_GetBlendModeDstColorFactor(blendMode);
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SDL_BlendFactor dstAlphaFactor = SDL_GetBlendModeDstAlphaFactor(blendMode);
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SDL_BlendOperation alphaOperation = SDL_GetBlendModeAlphaOperation(blendMode);
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if (GetBlendFunc(srcColorFactor) == GL_INVALID_ENUM ||
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GetBlendFunc(srcAlphaFactor) == GL_INVALID_ENUM ||
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GetBlendEquation(colorOperation) == GL_INVALID_ENUM ||
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GetBlendFunc(dstColorFactor) == GL_INVALID_ENUM ||
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GetBlendFunc(dstAlphaFactor) == GL_INVALID_ENUM ||
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GetBlendEquation(alphaOperation) == GL_INVALID_ENUM) {
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return SDL_FALSE;
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}
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if ((srcColorFactor != srcAlphaFactor || dstColorFactor != dstAlphaFactor) && !data->GL_OES_blend_func_separate_supported) {
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return SDL_FALSE;
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}
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if (colorOperation != alphaOperation && !data->GL_OES_blend_equation_separate_supported) {
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return SDL_FALSE;
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}
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if (colorOperation != SDL_BLENDOPERATION_ADD && !data->GL_OES_blend_subtract_supported) {
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return SDL_FALSE;
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}
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return SDL_TRUE;
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}
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static SDL_INLINE int
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power_of_2(int input)
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{
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@ -739,37 +822,28 @@ GLES_SetColor(GLES_RenderData * data, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
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}
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static void
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GLES_SetBlendMode(GLES_RenderData * data, int blendMode)
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GLES_SetBlendMode(GLES_RenderData * data, SDL_BlendMode blendMode)
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{
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if (blendMode != data->current.blendMode) {
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switch (blendMode) {
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case SDL_BLENDMODE_NONE:
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if (blendMode == SDL_BLENDMODE_NONE) {
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data->glDisable(GL_BLEND);
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break;
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case SDL_BLENDMODE_BLEND:
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} else {
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data->glEnable(GL_BLEND);
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if (data->GL_OES_blend_func_separate_supported) {
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data->glBlendFuncSeparateOES(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
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data->glBlendFuncSeparateOES(GetBlendFunc(SDL_GetBlendModeSrcColorFactor(blendMode)),
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GetBlendFunc(SDL_GetBlendModeDstColorFactor(blendMode)),
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GetBlendFunc(SDL_GetBlendModeSrcAlphaFactor(blendMode)),
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GetBlendFunc(SDL_GetBlendModeDstAlphaFactor(blendMode)));
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} else {
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data->glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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data->glBlendFunc(GetBlendFunc(SDL_GetBlendModeSrcColorFactor(blendMode)),
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GetBlendFunc(SDL_GetBlendModeDstColorFactor(blendMode)));
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}
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break;
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case SDL_BLENDMODE_ADD:
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data->glEnable(GL_BLEND);
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if (data->GL_OES_blend_func_separate_supported) {
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data->glBlendFuncSeparateOES(GL_SRC_ALPHA, GL_ONE, GL_ZERO, GL_ONE);
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} else {
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data->glBlendFunc(GL_SRC_ALPHA, GL_ONE);
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if (data->GL_OES_blend_equation_separate_supported) {
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data->glBlendEquationSeparateOES(GetBlendEquation(SDL_GetBlendModeColorOperation(blendMode)),
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GetBlendEquation(SDL_GetBlendModeAlphaOperation(blendMode)));
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} else if (data->GL_OES_blend_subtract_supported) {
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data->glBlendEquationOES(GetBlendEquation(SDL_GetBlendModeColorOperation(blendMode)));
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}
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break;
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case SDL_BLENDMODE_MOD:
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data->glEnable(GL_BLEND);
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if (data->GL_OES_blend_func_separate_supported) {
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data->glBlendFuncSeparateOES(GL_ZERO, GL_SRC_COLOR, GL_ZERO, GL_ONE);
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} else {
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data->glBlendFunc(GL_ZERO, GL_SRC_COLOR);
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}
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break;
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}
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data->current.blendMode = blendMode;
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}
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