Examples: DirectX10/11/12, Allegro, Marmalade: Render functions early out when display size is zero (minimized). (#2496)

docs/CHANGELOG.txt

@@ -61,6 +61,7 @@ Other Changes:
 - Examples: Vulkan: Avoid passing negative coordinates to vkCmdSetScissor, which debug validation layers do not like.
 - Examples: Vulkan: Added ImGui_ImplVulkan_SetMinImageCount() to change min image count at runtime. (#2071) [@nathanvoglsam]
 - Examples: DirectX9: Fixed erroneous assert in ImGui_ImplDX9_InvalidateDeviceObjects(). (#2454)
+- Examples: DirectX10/11/12, Allegro, Marmalade: Render functions early out when display size is zero (minimized). (#2496)
 - Examples: GLUT: Fixed existing FreeGLUT example to work with regular GLUT. (#2465) [@andrewwillmott]
 - Examples: GLUT: Renamed imgui_impl_freeglut.cpp/.h to imgui_impl_glut.cpp/.h. (#2465) [@andrewwillmott]
 - Examples: GLUT: Made io.DeltaTime always > 0. (#2430)

examples/imgui_impl_allegro5.cpp

@@ -64,6 +64,10 @@ struct ImDrawVertAllegro
 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
 void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
 {
+    // Avoid rendering when minimized
+    if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
+        return;
+
     // Backup Allegro state that will be modified
     ALLEGRO_TRANSFORM last_transform = *al_get_current_transform();
     ALLEGRO_TRANSFORM last_projection_transform = *al_get_current_projection_transform();

examples/imgui_impl_dx10.cpp

@@ -59,6 +59,10 @@ struct VERTEX_CONSTANT_BUFFER
 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
 void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
 {
+    // Avoid rendering when minimized
+    if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
+        return;
+
     ID3D10Device* ctx = g_pd3dDevice;
 
     // Create and grow vertex/index buffers if needed

examples/imgui_impl_dx11.cpp

@@ -59,6 +59,10 @@ struct VERTEX_CONSTANT_BUFFER
 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
 void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
 {
+    // Avoid rendering when minimized
+    if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
+        return;
+
     ID3D11DeviceContext* ctx = g_pd3dDeviceContext;
 
     // Create and grow vertex/index buffers if needed

examples/imgui_impl_dx12.cpp

@@ -62,6 +62,10 @@ struct VERTEX_CONSTANT_BUFFER
 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
 void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandList* ctx)
 {
+    // Avoid rendering when minimized
+    if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
+        return;
+
     // FIXME: I'm assuming that this only gets called once per frame!
     // If not, we can't just re-allocate the IB or VB, we'll have to do a proper allocator.
     g_frameIndex = g_frameIndex + 1;

examples/imgui_impl_marmalade.cpp

@@ -40,6 +40,10 @@ static ImVec2       g_RenderScale = ImVec2(1.0f,1.0f);
 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
 void ImGui_Marmalade_RenderDrawData(ImDrawData* draw_data)
 {
+    // Avoid rendering when minimized
+    if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
+        return;
+
     // Render command lists
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {