We now handle HiDPI correctly, and touches are clamped to the viewport. So
if you are rendering to a logical 640x480 in a 720p window, and touch the
letterboxing at point (640,700), it will report the touch at (0.5,1.0) instead
of outside the documented range.
From hmk:
"When scaling is enabled (e.g. via SDL_RenderSetLogicalSize, size not equal
to window size), mouse motion events are also scaled. Small motions are
rounded up (SDL_max() when the value after scaling is less than 1), while
larger motions are truncated by the floating point -> integer conversion.
https://hg.libsdl.org/SDL/file/b18197f9bf9d/src/render/SDL_render.c#l658
The end result feels something like mouse reverse mouse acceleration + angle
snapping at low speeds, but less consistent (amount of truncation & rounding
depends on how fast the mouse is moved) and potentially much worse if the
scaling factor is large. This pretty much makes it useless for anything
where you need precise mouse aiming (think of games). I suspect this is why
aiming gets so terrible in some games that let you use scaling to reduce the
render resolution (e.g. Ion Fury).
With 4x4 scaling, I can reproduce a situation where it takes three fast flicks
of the mouse across the pad to undo one slow sweep across the pad. In other
words, extreme reverse acceleration. This does not happen when scaling is
disabled.
Furthermore, any game that uses relative mouse motion events for 3D camera
rotation probably wants the raw mouse deltas and not a value that depends on
scaling and resolution and rounding and truncation. Ideal camera rotation
just takes mouse input, multiplies it by sensitivity, and adds it to the
angle-in-radians or whatever measure is used for yaw & pitch. Pixels and
screen resolution or window dimensions should not be a part of the equation
at all, even if it could be implemented without rounding errors.
[...]
This [patch] completely eliminates angle snapping for me, and makes
sensitivity consistent. In other words, it's completely usable for, say,
aiming in a first person shooter."
Partially fixes Bugzilla #4811.
Konrad
This kind of blending is rather quite useful and in my opinion should be available for all renderers. I do need it myself, but since I didn't want to use a custom blending mode which is supported only by certain renderers (e.g. not in software which is quite important for me) I did write implementation of SDL_BLENDMODE_MUL for all renderers altogether.
SDL_BLENDMODE_MUL implements following equation:
dstRGB = (srcRGB * dstRGB) + (dstRGB * (1-srcA))
dstA = (srcA * dstA) + (dstA * (1-srcA))
Background:
https://i.imgur.com/UsYhydP.png
Blended texture:
https://i.imgur.com/0juXQcV.png
Result for SDL_BLENDMODE_MOD:
https://i.imgur.com/wgNSgUl.png
Result for SDL_BLENDMODE_MUL:
https://i.imgur.com/Veokzim.png
I think I did cover all possibilities within included patch, but I didn't write any tests for SDL_BLENDMODE_MUL, so it would be lovely if someone could do it.
Konrad
This was something rather trivial to add, but asked at least several times before (I did google about it as well).
It should be possible to dynamically change scaling mode of the texture. It is actually trivial task, but until now it was only possible with a hint before creating a texture.
I needed it for my game as well, so I took the liberty of writing it myself.
This patch adds following functions:
SDL_SetTextureScaleMode(SDL_Texture * texture, SDL_ScaleMode scaleMode);
SDL_GetTextureScaleMode(SDL_Texture * texture, SDL_ScaleMode *scaleMode);
That way you can change texture scaling on the fly.
Sylvain
Currently SDL_CreateTextureFromSurface picks first valid format, and do a conversion.
format = renderer->info.texture_formats[0];
for (i = 0; i < renderer->info.num_texture_formats; ++i) {
if (!SDL_ISPIXELFORMAT_FOURCC(renderer->info.texture_formats[i]) &&
SDL_ISPIXELFORMAT_ALPHA(renderer->info.texture_formats[i]) == needAlpha) {
format = renderer->info.texture_formats[i];
break;
It could try to find a better format, for instance :
if SDL_Surface has no Amask, but a colorkey :
if surface fmt is RGB888, try to pick ARGB8888 renderer fmt
if surface fmt is BGR888, try to pick ABGR8888 renderer fmt
else
try to pick the same renderer format as surface fmt
if no format has been picked, use the fallback.
I think it goes with bug 4290 fastpath BlitNtoN
when you expand a surface with pixel format of size 24 to 32, there is a fast path possible.
So with this issue:
- if you have a surface with colorkey (RGB or BGR, not palette), it takes a renderer format where the conversion is faster.
(it avoids, if possible, RGB -> ABGR which means switching RGB to BGR)
- if you have a surface ABGR format, it try to take the ABGR from the renderer.
(it avoids, if possible, ABGR -> ARGB, which means switch RGB to BGR)
This is the best option for macOS and iOS, the only platforms with Metal.
Pre-Metal versions of these platforms will fall back to OpenGL (ES), as
appropriate.
Huge thanks to Alexander Szpakowski, who worked incredibly hard to get the
Metal renderer to such a high-quality state!
Ivan Epifanov
Sylvain
Ryan C. Gordon
Vanfanel
Sam Lantinga
hmk
Alex Szpakowski
