Unexpected SDL_BLENDMODE differences in SDL_CreateTextureFromSurface() and SDL_CreateTexture()

[Green-Sky]

When creating a surface using SDL_CreateSurfaceFrom() with SDL_PIXELFORMAT_RGBA32, blend mode is set to SDL_BLENDMODE_BLEND. SDL_CreateTextureFromSurface() then goes in and copies the blend mode from the surface to the texture. Due to limitations on setting properties (static/streaming) I went with SDL_CreateTexture(), which obv does not copy the blend mode.

This whole behavoir difference is a bit unintuitive, and I propose to make the behavoir the same for surfaces and textures.

edit: just found out its actually worse, the blend mode is always set to BLEND if the source surface has alpha, and copied otherwise:

SDL/src/render/SDL_render.c

Lines 1619 to 1625 in fd2b9c0

	if (SDL_SurfaceHasColorKey(surface)) {
	/* We converted to a texture with alpha format */
	SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
	} else {
	SDL_GetSurfaceBlendMode(surface, &blendMode);
	SDL_SetTextureBlendMode(texture, blendMode);
	}

[1bsyl]

there was this PR related: #4690

[slouken]

Fixed, thanks!