creating a skimage (gpu-backend), and throwing it into a non-gl thread would cause program crash

[han “mor” wang]

hello everyone,

    when I was using skia, I confront a issue.

   First I create skimage (gpu-backend ,using makeImageSnapshot) in gl-contex thread, and post into anothe non-gl thread.

   As a result, program crased becuase of invoking gl-function in a non-gl thread. I wonder if skia should keep gl-resource from releasing in a non-gl thread. I upload a patch to try to solve it. (gerrit)I would be very thankful if you could review the uploaded code  in your spare time.

I post source code in below 

static void run() {

sk_sp<SkImage> img;

int i = 0;

int j = 0;

std::vector<sk_sp<SkImage>> vc;

while (1) {

std::unique_lock<std::mutex> lck(mtx);

while (!run_loop.load()) {

std::cout<< "i am waiting" <<std::endl;

cv.wait(lck);

}

{

std::lock_guard<std::mutex> lck(task_mutex);

if (!Tasks.empty()) {

auto tmp = Tasks.front()();

img = tmp;

Tasks.pop();

}

}

if (img) {

int width = img->width();

i++;

j++;

//std::cout <<" width is" <<width << " i: "<<i++ <<std::endl;

}

}

}

int main() {

initGLFWWindow(window_width, window_height);

init_skia(window_width, window_height);

std::thread t(run);

std::cout << " skia init ok " << std::endl;

SkCanvas *canvas = g_surface->getCanvas();

int i = 0;

bool first = true;

while (!glfwWindowShouldClose(g_window)) {

canvas->drawColor(SK_ColorWHITE);

SkRect rect = SkRect::MakeXYWH(0,0,250,250);

SkPaint paint;

paint.setColor(SK_ColorRED);

canvas->drawRect(rect,paint);

if (i == 0) {

//i++;

{

auto tmpImage = g_surface->makeImageSnapshot();

SkBitmap bitmap;

// if (!tmpImage->asLegacyBitmap(&bitmap)) {

// return 0;

// }

std::lock_guard<std::mutex> lock(task_mutex);

Tasks.push([tmpImage]() {

return tmpImage;

});

}

if (first) {

run_loop.store(true);

cv.notify_all();

first = false;

}

//t.join();

}

g_context->flush();

g_context->submit();

glfwSwapBuffers(g_window);

glfwPollEvents();

}

}