improve window size handling in mock backend

Author: nmwsharp

src/render/mock_opengl/mock_gl_engine.cpp

@@ -1733,22 +1733,31 @@ void MockGLEngine::hideWindow() {}
 
 void MockGLEngine::updateWindowSize(bool force) {
 
-  // this silly code mimicks the gl backend version, but it is important that we preserve
+  // This silly code mimicks the gl backend version, but it is important that we preserve
   // the view::bufferWidth, etc, otherwise it is impossible to manually set the window size
-  // in the mock backend (which appears in unit tests, etc)
-  int newBufferWidth = view::bufferWidth;
-  int newBufferHeight = view::bufferHeight;
+  // in the mock backend (which appears in unit tests, etc).
+  // In this case, we just let the buffer size follow the window size 1:1
+  int newBufferWidth = view::windowWidth;
+  int newBufferHeight = view::windowHeight;
   int newWindowWidth = view::windowWidth;
   int newWindowHeight = view::windowHeight;
 
   if (force || newBufferWidth != view::bufferWidth || newBufferHeight != view::bufferHeight ||
       newWindowHeight != view::windowHeight || newWindowWidth != view::windowWidth) {
     // Basically a resize callback
     requestRedraw();
+    
+    // prevent any division by zero for e.g. aspect ratio calcs
+    if (newBufferHeight == 0) newBufferHeight = 1;
+    if (newWindowHeight == 0) newWindowHeight = 1;
+
     view::bufferWidth = newBufferWidth;
     view::bufferHeight = newBufferHeight;
     view::windowWidth = newWindowWidth;
     view::windowHeight = newWindowHeight;
+
+    render::engine->resizeScreenBuffers();
+    render::engine->setScreenBufferViewports();
   }
 }
 

test/src/basics_test.cpp

@@ -114,15 +114,25 @@ TEST_F(PolyscopeTest, EmptyBuffer) {
 TEST_F(PolyscopeTest, WindowProperties) {
 
   // set/get window size
-  polyscope::view::setWindowSize(300, 400);
+  int32_t target_w = 500;
+  int32_t target_h = 300;
+  polyscope::view::setWindowSize(target_w, target_h);
   int32_t w, h;
   std::tie(w, h) = polyscope::view::getWindowSize();
-  EXPECT_EQ(w, 300);
-  EXPECT_EQ(h, 400);
+  EXPECT_EQ(w, target_w);
+  EXPECT_EQ(h, target_h);
+
+  polyscope::show(3);
 
   // get buffer size
   // (hard to say what this should be, given hi-dpi etc)
-  std::tie(w, h) = polyscope::view::getBufferSize();
+  int32_t buffer_w, buffer_h;
+  std::tie(buffer_w, buffer_h) = polyscope::view::getBufferSize();
+
+  float target_aspect = target_w / static_cast<float>(target_h);
+  float buffer_aspect = buffer_w / static_cast<float>(buffer_h);
+  EXPECT_NEAR(target_aspect, buffer_aspect, 0.01);
+
 
   // resizable
   polyscope::view::setWindowResizable(false);