Need to re-construct all the textures after resizing window?

SDL Development
1

I am now developing my game using SDL2. All pictures are store in textures.
The problem is that if I resize the window, it stops updating images.
I turns out I can fix this problem by re-create the renderer and all textures. However, this is not a easy work because the textures are managed in many classes and I need to write a lot of code to do the re-creation (and this method is not elegant).

Is there better ways to handle window resizing issue? Thanks in advance.

2

Which function are you using to resize the window, or is it user-resizable?
Which platform and renderer are you using?

Jonny D

3

Hi Jonny,
I tried both (i.e. use SDL_SetWindowSize or create window with SDL_WINDOW_RESIZABLE flag). Both have the same problem.
I am in Win7, using default renderer (should be hardware renderer).

Jonny D wrote:> Which function are you using to resize the window, or is it user-resizable? ?Which platform and renderer are you using?

Jonny D

4

I did some tests for this problem.
Test 1: blitting order: surface -> texture -> window. Then SDL2 can handle resize automatically. When window resizes, image resizes too.
code of test1:
int sdltest() {
SDL_Window* window;
SDL_Renderer* renderer;
if (SDL_Init(SDL_INIT_EVERYTHING) < 0) return 1;
if (!IMG_Init(IMG_INIT_PNG)) return 1;
window = SDL_CreateWindow(“test”, SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED, 640, 480, SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE | SDL_RENDERER_PRESENTVSYNC);
SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, “linear”);
renderer = SDL_CreateRenderer(window, -1, 0);
SDL_Surface *_mainpic = IMG_Load(“somepic.png”);
SDL_Texture *_maintx = SDL_CreateTextureFromSurface(renderer, _mainpic);
SDL_FreeSurface(_mainpic);
SDL_Event ev;
while (true){
while (SDL_PollEvent(&ev))
if (ev.type == SDL_QUIT) return 0;
SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
SDL_RenderClear(renderer);
SDL_RenderCopy(renderer, _maintx, NULL, NULL);
SDL_RenderPresent(renderer);
SDL_Delay(10);
}
return 0;
}

Test 2: blitting order: surface -> texture -> another texture -> window. Then SDL2 can not handle resize. When window resizes, image stops updating. If I drag the window to smaller size, the image will be cut to the window size (not zoom), and will not restore even when I drag the window to original size.
code of test2:

Code:

int sdltest() {
SDL_Window* window;
SDL_Renderer* renderer;
if (SDL_Init(SDL_INIT_EVERYTHING) < 0) return 1;
if (!IMG_Init(IMG_INIT_PNG)) return 1;
window = SDL_CreateWindow(“test”, SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED, 640, 480, SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE | SDL_RENDERER_PRESENTVSYNC);
SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, “linear”);
renderer = SDL_CreateRenderer(window, -1, 0);
SDL_Surface *_mainpic = IMG_Load(“somepic.png”);
SDL_Texture *_maintx = SDL_CreateTextureFromSurface(renderer, _mainpic);
SDL_Texture *tex = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_TARGET, 640, 480);
SDL_FreeSurface(_mainpic);
SDL_Event ev;
while (true){
while (SDL_PollEvent(&ev))
if (ev.type == SDL_QUIT) return 0;
SDL_SetRenderTarget(renderer, NULL);
SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
SDL_RenderClear(renderer);
SDL_SetRenderTarget(renderer, tex);
SDL_RenderCopy(renderer, _maintx, NULL, NULL);
SDL_SetRenderTarget(renderer, NULL);
SDL_RenderCopy(renderer, tex, NULL, NULL);
SDL_RenderPresent(renderer);
SDL_Delay(10);
}
return 0;
}

Jonny D wrote:> Which function are you using to resize the window, or is it user-resizable? ?Which platform and renderer are you using?

Jonny D

5

you need to
(a) Destroy the render target texture
(b) Resize Window
© Re-create render target texture.

If that is not possible then
(a) Resize Window
(b) Destroy Render Target Texture
© Reset device (Calling SDL_Clear() + SDL_RenderPresent() will do this.
(d) Re-create render target
(e) Ready to go.
(f) Problems sometimes occur in Resetting Video device, it does not
always work.

On 2/19/2014 11:01 AM, RunningOn wrote:> I did some tests for this problem.

Test 1: blitting order: surface -> texture -> window. Then SDL2 can
handle resize automatically. When window resizes, image resizes too.
code of test1:
int sdltest() {
SDL_Window* window;
SDL_Renderer* renderer;
if (SDL_Init(SDL_INIT_EVERYTHING) < 0) return 1;
if (!IMG_Init(IMG_INIT_PNG)) return 1;
window = SDL_CreateWindow(“test”, SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED, 640, 480, SDL_WINDOW_SHOWN |
SDL_WINDOW_RESIZABLE | SDL_RENDERER_PRESENTVSYNC);
SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, “linear”);
renderer = SDL_CreateRenderer(window, -1, 0);
SDL_Surface *_mainpic = IMG_Load(“somepic.png”);
SDL_Texture *_maintx = SDL_CreateTextureFromSurface(renderer, _mainpic);
SDL_FreeSurface(_mainpic);
SDL_Event ev;
while (true){
while (SDL_PollEvent(&ev))
if (ev.type == SDL_QUIT) return 0;
SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
SDL_RenderClear(renderer);
SDL_RenderCopy(renderer, _maintx, NULL, NULL);
SDL_RenderPresent(renderer);
SDL_Delay(10);
}
return 0;
}

Test 2: blitting order: surface -> texture -> another texture ->
window. Then SDL2 can not handle resize. When window resizes, image
stops updating. If I drag the window to smaller size, the image will
be cut to the window size (not zoom), and will not restore even when I
drag the window to original size.
code of test2:

Code:

int sdltest() {
SDL_Window* window;
SDL_Renderer* renderer;
if (SDL_Init(SDL_INIT_EVERYTHING) < 0) return 1;
if (!IMG_Init(IMG_INIT_PNG)) return 1;
window = SDL_CreateWindow(“test”, SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED, 640, 480, SDL_WINDOW_SHOWN |
SDL_WINDOW_RESIZABLE | SDL_RENDERER_PRESENTVSYNC);
SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, “linear”);
renderer = SDL_CreateRenderer(window, -1, 0);
SDL_Surface *_mainpic = IMG_Load(“somepic.png”);
SDL_Texture *_maintx = SDL_CreateTextureFromSurface(renderer,
_mainpic);
SDL_Texture *tex = SDL_CreateTexture(renderer,
SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_TARGET, 640, 480);
SDL_FreeSurface(_mainpic);
SDL_Event ev;
while (true){
while (SDL_PollEvent(&ev))
if (ev.type == SDL_QUIT) return 0;
SDL_SetRenderTarget(renderer, NULL);
SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
SDL_RenderClear(renderer);
SDL_SetRenderTarget(renderer, tex);
SDL_RenderCopy(renderer, _maintx, NULL, NULL);
SDL_SetRenderTarget(renderer, NULL);
SDL_RenderCopy(renderer, tex, NULL, NULL);
SDL_RenderPresent(renderer);
SDL_Delay(10);
}
return 0;
}

Jonny D wrote:
Which function are you using to resize the window, or is it
user-resizable? Which platform and renderer are you using?

Jonny D

SDL mailing list
SDL at lists.libsdl.org
http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org

–
Pallav Nawani
Game Designer/CEO
http://www.ironcode.com
Twitter: http://twitter.com/Ironcode_Gaming
Facebook: http://www.facebook.com/Ironcode.Gaming

6

It’s a headache to destroy all the render target textures because there are many. But it is achievable at least.
If no better solutions I will do this.
Thanks.

Pallav Nawani wrote:> you need to

(a) Destroy the render target texture
(b) Resize Window
© Re-create render target texture.

If that is not possible then
(a) Resize Window
(b) Destroy Render Target Texture
© Reset device (Calling SDL_Clear() + SDL_RenderPresent() will do this.
(d) Re-create render target
(e) Ready to go.
(f) Problems sometimes occur in Resetting Video device, it does not
always work.

7

Try the latest SDL2 Hg version. There seems to be a fix for this
particular problem. The driver tries to automatically create & destroy
the render target textures and reset the device, then sends an event:
SDL_RENDER_TARGETS_RESET

On 2/19/2014 11:01 AM, RunningOn wrote:> I did some tests for this problem.

Test 1: blitting order: surface -> texture -> window. Then SDL2 can
handle resize automatically. When window resizes, image resizes too.
code of test1:
int sdltest() {
SDL_Window* window;
SDL_Renderer* renderer;
if (SDL_Init(SDL_INIT_EVERYTHING) < 0) return 1;
if (!IMG_Init(IMG_INIT_PNG)) return 1;
window = SDL_CreateWindow(“test”, SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED, 640, 480, SDL_WINDOW_SHOWN |
SDL_WINDOW_RESIZABLE | SDL_RENDERER_PRESENTVSYNC);
SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, “linear”);
renderer = SDL_CreateRenderer(window, -1, 0);
SDL_Surface *_mainpic = IMG_Load(“somepic.png”);
SDL_Texture *_maintx = SDL_CreateTextureFromSurface(renderer, _mainpic);
SDL_FreeSurface(_mainpic);
SDL_Event ev;
while (true){
while (SDL_PollEvent(&ev))
if (ev.type == SDL_QUIT) return 0;
SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
SDL_RenderClear(renderer);
SDL_RenderCopy(renderer, _maintx, NULL, NULL);
SDL_RenderPresent(renderer);
SDL_Delay(10);
}
return 0;
}

Test 2: blitting order: surface -> texture -> another texture ->
window. Then SDL2 can not handle resize. When window resizes, image
stops updating. If I drag the window to smaller size, the image will
be cut to the window size (not zoom), and will not restore even when I
drag the window to original size.
code of test2:

Code:

int sdltest() {
SDL_Window* window;
SDL_Renderer* renderer;
if (SDL_Init(SDL_INIT_EVERYTHING) < 0) return 1;
if (!IMG_Init(IMG_INIT_PNG)) return 1;
window = SDL_CreateWindow(“test”, SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED, 640, 480, SDL_WINDOW_SHOWN |
SDL_WINDOW_RESIZABLE | SDL_RENDERER_PRESENTVSYNC);
SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, “linear”);
renderer = SDL_CreateRenderer(window, -1, 0);
SDL_Surface *_mainpic = IMG_Load(“somepic.png”);
SDL_Texture *_maintx = SDL_CreateTextureFromSurface(renderer,
_mainpic);
SDL_Texture *tex = SDL_CreateTexture(renderer,
SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_TARGET, 640, 480);
SDL_FreeSurface(_mainpic);
SDL_Event ev;
while (true){
while (SDL_PollEvent(&ev))
if (ev.type == SDL_QUIT) return 0;
SDL_SetRenderTarget(renderer, NULL);
SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
SDL_RenderClear(renderer);
SDL_SetRenderTarget(renderer, tex);
SDL_RenderCopy(renderer, _maintx, NULL, NULL);
SDL_SetRenderTarget(renderer, NULL);
SDL_RenderCopy(renderer, tex, NULL, NULL);
SDL_RenderPresent(renderer);
SDL_Delay(10);
}
return 0;
}

Jonny D wrote:
Which function are you using to resize the window, or is it
user-resizable? Which platform and renderer are you using?

Jonny D

SDL mailing list
SDL at lists.libsdl.org
http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org

–
Pallav Nawani
Game Designer/CEO
http://www.ironcode.com
Twitter: http://twitter.com/Ironcode_Gaming
Facebook: http://www.facebook.com/Ironcode.Gaming

8

Thanks.
One more question, if the render targets are automatically re-created, what must I do to response SDL_RENDER_TARGETS_RESET ?

Pallav Nawani wrote:> Try the latest SDL2 Hg version. There seems to be a fix for this

particular problem. The driver tries to automatically create & destroy
the render target textures and reset the device, then sends an event:
SDL_RENDER_TARGETS_RESET

9

The textures are re-allocated but the image data in them is lost. You can
re-create the data in the render target texture when you get the event.

On Sat, Feb 22, 2014 at 5:12 PM, RunningOn wrote:> Thanks.

One more question, if the render targets are automatically re-created,
what must I do to response SDL_RENDER_TARGETS_RESET ?

Pallav Nawani wrote:

Try the latest SDL2 Hg version. There seems to be a fix for this
particular problem. The driver tries to automatically create & destroy
the render target textures and reset the device, then sends an event:
SDL_RENDER_TARGETS_RESET

SDL mailing list
SDL at lists.libsdl.org
http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org

–
Pallav Nawani
IronCode Gaming Private Limited
Website: http://www.ironcode.com
Twitter: http://twitter.com/Ironcode_Gaming
Facebook: http://www.facebook.com/Ironcode.Gaming
Mobile: 9997478768