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Backends: OSX, Metal: Store backend data in a per-context struct, all…
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…owing to use these backends with multiple contexts. (#5203, #5221, #4141)

# Conflicts:
#	docs/CHANGELOG.txt
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@noisewuwei @ocornut
noisewuwei authored and ocornut committed Apr 27, 2022
1 parent 0468997 commit e54db4e
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Showing 3 changed files with 102 additions and 62 deletions.
55 changes: 36 additions & 19 deletions backends/imgui_impl_metal.mm
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@

// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
// 2022-04-27: Misc: Store backend data in a per-context struct, allowing to use this backend with multiple contexts.
// 2022-01-03: Metal: Ignore ImDrawCmd where ElemCount == 0 (very rare but can technically be manufactured by user code).
// 2021-12-30: Metal: Added Metal C++ support. Enable with '#define IMGUI_IMPL_METAL_CPP' in your imconfig.h file.
// 2021-08-24: Metal: Fixed a crash when clipping rect larger than framebuffer is submitted. (#4464)
Expand Down Expand Up @@ -54,6 +55,7 @@ - (instancetype)initWithRenderPassDescriptor:(MTLRenderPassDescriptor *)renderPa
// renderer backend. Stores the render pipeline state cache and the default
// font texture, and manages the reusable buffer cache.
@interface MetalContext : NSObject
@property (nonatomic, strong) id<MTLDevice> device;
@property (nonatomic, strong) id<MTLDepthStencilState> depthStencilState;
@property (nonatomic, strong) FramebufferDescriptor *framebufferDescriptor; // framebuffer descriptor for current frame; transient
@property (nonatomic, strong) NSMutableDictionary *renderPipelineStateCache; // pipeline cache; keyed on framebuffer descriptors
Expand All @@ -77,7 +79,16 @@ - (void)renderDrawData:(ImDrawData *)drawData
commandEncoder:(id<MTLRenderCommandEncoder>)commandEncoder;
@end

static MetalContext *g_sharedMetalContext = nil;
struct ImGui_ImplMetal_Data
{
MetalContext* SharedMetalContext;

ImGui_ImplMetal_Data() { memset(this, 0, sizeof(*this)); }
};

static ImGui_ImplMetal_Data* ImGui_ImplMetal_CreateBackendData() { return IM_NEW(ImGui_ImplMetal_Data)(); }
static ImGui_ImplMetal_Data* ImGui_ImplMetal_GetBackendData() { return ImGui::GetCurrentContext() ? (ImGui_ImplMetal_Data*)ImGui::GetIO().BackendRendererUserData : NULL; }
static void ImGui_ImplMetal_DestroyBackendData() { IM_DELETE(ImGui_ImplMetal_GetBackendData()); }

#ifdef IMGUI_IMPL_METAL_CPP

Expand Down Expand Up @@ -119,68 +130,73 @@ bool ImGui_ImplMetal_CreateDeviceObjects(MTL::Device* device)

bool ImGui_ImplMetal_Init(id<MTLDevice> device)
{
ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_CreateBackendData();
ImGuiIO& io = ImGui::GetIO();
io.BackendRendererUserData = (void*)bd;
io.BackendRendererName = "imgui_impl_metal";
io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset; // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.

static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
g_sharedMetalContext = [[MetalContext alloc] init];
});

ImGui_ImplMetal_CreateDeviceObjects(device);
bd->SharedMetalContext = [[MetalContext alloc] init];
bd->SharedMetalContext.device = device;

return true;
}

void ImGui_ImplMetal_Shutdown()
{
ImGui_ImplMetal_DestroyDeviceObjects();
ImGui_ImplMetal_DestroyBackendData();
}

void ImGui_ImplMetal_NewFrame(MTLRenderPassDescriptor *renderPassDescriptor)
{
IM_ASSERT(g_sharedMetalContext != nil && "No Metal context. Did you call ImGui_ImplMetal_Init() ?");
ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
IM_ASSERT(bd->SharedMetalContext != nil && "No Metal context. Did you call ImGui_ImplMetal_Init() ?");
bd->SharedMetalContext.framebufferDescriptor = [[FramebufferDescriptor alloc] initWithRenderPassDescriptor:renderPassDescriptor];

g_sharedMetalContext.framebufferDescriptor = [[FramebufferDescriptor alloc] initWithRenderPassDescriptor:renderPassDescriptor];
if (bd->SharedMetalContext.depthStencilState == nil)
ImGui_ImplMetal_CreateDeviceObjects(bd->SharedMetalContext.device);
}

// Metal Render function.
void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data, id<MTLCommandBuffer> commandBuffer, id<MTLRenderCommandEncoder> commandEncoder)
{
[g_sharedMetalContext renderDrawData:draw_data commandBuffer:commandBuffer commandEncoder:commandEncoder];
ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
[bd->SharedMetalContext renderDrawData:draw_data commandBuffer:commandBuffer commandEncoder:commandEncoder];
}

bool ImGui_ImplMetal_CreateFontsTexture(id<MTLDevice> device)
{
[g_sharedMetalContext makeFontTextureWithDevice:device];

ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
ImGuiIO& io = ImGui::GetIO();
io.Fonts->SetTexID((__bridge void *)g_sharedMetalContext.fontTexture); // ImTextureID == void*
[bd->SharedMetalContext makeFontTextureWithDevice:device];
io.Fonts->SetTexID((__bridge void *)bd->SharedMetalContext.fontTexture); // ImTextureID == void*

return (g_sharedMetalContext.fontTexture != nil);
return (bd->SharedMetalContext.fontTexture != nil);
}

void ImGui_ImplMetal_DestroyFontsTexture()
{
ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
ImGuiIO& io = ImGui::GetIO();
g_sharedMetalContext.fontTexture = nil;
bd->SharedMetalContext.fontTexture = nil;
io.Fonts->SetTexID(nullptr);
}

bool ImGui_ImplMetal_CreateDeviceObjects(id<MTLDevice> device)
{
[g_sharedMetalContext makeDeviceObjectsWithDevice:device];

ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
[bd->SharedMetalContext makeDeviceObjectsWithDevice:device];
ImGui_ImplMetal_CreateFontsTexture(device);

return true;
}

void ImGui_ImplMetal_DestroyDeviceObjects()
{
ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
ImGui_ImplMetal_DestroyFontsTexture();
[g_sharedMetalContext emptyRenderPipelineStateCache];
[bd->SharedMetalContext emptyRenderPipelineStateCache];
}

#pragma mark - MetalBuffer implementation
Expand Down Expand Up @@ -458,8 +474,9 @@ - (void)setupRenderState:(ImDrawData *)drawData
vertexBuffer:(MetalBuffer *)vertexBuffer
vertexBufferOffset:(size_t)vertexBufferOffset
{
ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
[commandEncoder setCullMode:MTLCullModeNone];
[commandEncoder setDepthStencilState:g_sharedMetalContext.depthStencilState];
[commandEncoder setDepthStencilState:bd->SharedMetalContext.depthStencilState];

// Setup viewport, orthographic projection matrix
// Our visible imgui space lies from draw_data->DisplayPos (top left) to
Expand Down
107 changes: 64 additions & 43 deletions backends/imgui_impl_osx.mm
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Expand Up @@ -23,6 +23,7 @@

// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
// 2022-04-27: Misc: Store backend data in a per-context struct, allowing to use this backend with multiple contexts.
// 2022-03-22: Inputs: Monitor NSKeyUp events to catch missing keyUp for key when user press Cmd + key
// 2022-02-07: Inputs: Forward keyDown/keyUp events to OS when unused by dear imgui.
// 2022-01-31: Fix building with old Xcode versions that are missing gamepad features.
Expand Down Expand Up @@ -57,13 +58,22 @@
@class KeyEventResponder;

// Data
static double g_HostClockPeriod = 0.0;
static double g_Time = 0.0;
static NSCursor* g_MouseCursors[ImGuiMouseCursor_COUNT] = {};
static bool g_MouseCursorHidden = false;
static ImFocusObserver* g_FocusObserver = nil;
static KeyEventResponder* g_KeyEventResponder = nil;
static NSTextInputContext* g_InputContext = nil;
struct ImGui_ImplOSX_Data
{
double HostClockPeriod;
double Time;
NSCursor* MouseCursors[ImGuiMouseCursor_COUNT];
bool MouseCursorHidden;
ImFocusObserver* FocusObserver;
KeyEventResponder* KeyEventResponder;
NSTextInputContext* InputContext;

ImGui_ImplOSX_Data() { memset(this, 0, sizeof(*this)); }
};

static ImGui_ImplOSX_Data* ImGui_ImplOSX_CreateBackendData() { return IM_NEW(ImGui_ImplOSX_Data)(); }
static ImGui_ImplOSX_Data* ImGui_ImplOSX_GetBackendData() { return (ImGui_ImplOSX_Data*)ImGui::GetIO().BackendPlatformUserData; }
static void ImGui_ImplOSX_DestroyBackendData() { IM_DELETE(ImGui_ImplOSX_GetBackendData()); }

// Undocumented methods for creating cursors.
@interface NSCursor()
Expand All @@ -75,14 +85,16 @@ + (id)_windowResizeEastWestCursor;

static void InitHostClockPeriod()
{
ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
struct mach_timebase_info info;
mach_timebase_info(&info);
g_HostClockPeriod = 1e-9 * ((double)info.denom / (double)info.numer); // Period is the reciprocal of frequency.
bd->HostClockPeriod = 1e-9 * ((double)info.denom / (double)info.numer); // Period is the reciprocal of frequency.
}

static double GetMachAbsoluteTimeInSeconds()
{
return (double)mach_absolute_time() * g_HostClockPeriod;
ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
return (double)mach_absolute_time() * bd->HostClockPeriod;
}

/**
Expand Down Expand Up @@ -363,6 +375,8 @@ static ImGuiKey ImGui_ImplOSX_KeyCodeToImGuiKey(int key_code)
bool ImGui_ImplOSX_Init(NSView* view)
{
ImGuiIO& io = ImGui::GetIO();
ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_CreateBackendData();
io.BackendPlatformUserData = (void*)bd;

// Setup backend capabilities flags
io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors; // We can honor GetMouseCursor() values (optional)
Expand All @@ -372,16 +386,16 @@ bool ImGui_ImplOSX_Init(NSView* view)
io.BackendPlatformName = "imgui_impl_osx";

// Load cursors. Some of them are undocumented.
g_MouseCursorHidden = false;
g_MouseCursors[ImGuiMouseCursor_Arrow] = [NSCursor arrowCursor];
g_MouseCursors[ImGuiMouseCursor_TextInput] = [NSCursor IBeamCursor];
g_MouseCursors[ImGuiMouseCursor_ResizeAll] = [NSCursor closedHandCursor];
g_MouseCursors[ImGuiMouseCursor_Hand] = [NSCursor pointingHandCursor];
g_MouseCursors[ImGuiMouseCursor_NotAllowed] = [NSCursor operationNotAllowedCursor];
g_MouseCursors[ImGuiMouseCursor_ResizeNS] = [NSCursor respondsToSelector:@selector(_windowResizeNorthSouthCursor)] ? [NSCursor _windowResizeNorthSouthCursor] : [NSCursor resizeUpDownCursor];
g_MouseCursors[ImGuiMouseCursor_ResizeEW] = [NSCursor respondsToSelector:@selector(_windowResizeEastWestCursor)] ? [NSCursor _windowResizeEastWestCursor] : [NSCursor resizeLeftRightCursor];
g_MouseCursors[ImGuiMouseCursor_ResizeNESW] = [NSCursor respondsToSelector:@selector(_windowResizeNorthEastSouthWestCursor)] ? [NSCursor _windowResizeNorthEastSouthWestCursor] : [NSCursor closedHandCursor];
g_MouseCursors[ImGuiMouseCursor_ResizeNWSE] = [NSCursor respondsToSelector:@selector(_windowResizeNorthWestSouthEastCursor)] ? [NSCursor _windowResizeNorthWestSouthEastCursor] : [NSCursor closedHandCursor];
bd->MouseCursorHidden = false;
bd->MouseCursors[ImGuiMouseCursor_Arrow] = [NSCursor arrowCursor];
bd->MouseCursors[ImGuiMouseCursor_TextInput] = [NSCursor IBeamCursor];
bd->MouseCursors[ImGuiMouseCursor_ResizeAll] = [NSCursor closedHandCursor];
bd->MouseCursors[ImGuiMouseCursor_Hand] = [NSCursor pointingHandCursor];
bd->MouseCursors[ImGuiMouseCursor_NotAllowed] = [NSCursor operationNotAllowedCursor];
bd->MouseCursors[ImGuiMouseCursor_ResizeNS] = [NSCursor respondsToSelector:@selector(_windowResizeNorthSouthCursor)] ? [NSCursor _windowResizeNorthSouthCursor] : [NSCursor resizeUpDownCursor];
bd->MouseCursors[ImGuiMouseCursor_ResizeEW] = [NSCursor respondsToSelector:@selector(_windowResizeEastWestCursor)] ? [NSCursor _windowResizeEastWestCursor] : [NSCursor resizeLeftRightCursor];
bd->MouseCursors[ImGuiMouseCursor_ResizeNESW] = [NSCursor respondsToSelector:@selector(_windowResizeNorthEastSouthWestCursor)] ? [NSCursor _windowResizeNorthEastSouthWestCursor] : [NSCursor closedHandCursor];
bd->MouseCursors[ImGuiMouseCursor_ResizeNWSE] = [NSCursor respondsToSelector:@selector(_windowResizeNorthWestSouthEastCursor)] ? [NSCursor _windowResizeNorthWestSouthEastCursor] : [NSCursor closedHandCursor];

// Note that imgui.cpp also include default OSX clipboard handlers which can be enabled
// by adding '#define IMGUI_ENABLE_OSX_DEFAULT_CLIPBOARD_FUNCTIONS' in imconfig.h and adding '-framework ApplicationServices' to your linker command-line.
Expand Down Expand Up @@ -412,56 +426,60 @@ bool ImGui_ImplOSX_Init(NSView* view)
return s_clipboard.Data;
};

g_FocusObserver = [[ImFocusObserver alloc] init];
[[NSNotificationCenter defaultCenter] addObserver:g_FocusObserver
bd->FocusObserver = [[ImFocusObserver alloc] init];
[[NSNotificationCenter defaultCenter] addObserver:bd->FocusObserver
selector:@selector(onApplicationBecomeActive:)
name:NSApplicationDidBecomeActiveNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:g_FocusObserver
[[NSNotificationCenter defaultCenter] addObserver:bd->FocusObserver
selector:@selector(onApplicationBecomeInactive:)
name:NSApplicationDidResignActiveNotification
object:nil];

// Add the NSTextInputClient to the view hierarchy,
// to receive keyboard events and translate them to input text.
g_KeyEventResponder = [[KeyEventResponder alloc] initWithFrame:NSZeroRect];
g_InputContext = [[NSTextInputContext alloc] initWithClient:g_KeyEventResponder];
[view addSubview:g_KeyEventResponder];
bd->KeyEventResponder = [[KeyEventResponder alloc] initWithFrame:NSZeroRect];
bd->InputContext = [[NSTextInputContext alloc] initWithClient:bd->KeyEventResponder];
[view addSubview:bd->KeyEventResponder];

// Some events do not raise callbacks of AppView in some circumstances (for example when CMD key is held down).
// This monitor taps into global event stream and captures these events.
NSEventMask eventMask = NSEventMaskFromType(NSKeyUp) | NSEventMaskFlagsChanged;
[NSEvent addLocalMonitorForEventsMatchingMask:eventMask handler:^NSEvent * _Nullable(NSEvent *event)
{
ImGui_ImplOSX_HandleEvent(event, g_KeyEventResponder);
ImGui_ImplOSX_HandleEvent(event, bd->KeyEventResponder);
return event;
}];

io.SetPlatformImeDataFn = [](ImGuiViewport* viewport, ImGuiPlatformImeData* data) -> void
{
ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
if (data->WantVisible)
{
[g_InputContext activate];
[bd->InputContext activate];
}
else
{
[g_InputContext discardMarkedText];
[g_InputContext invalidateCharacterCoordinates];
[g_InputContext deactivate];
[bd->InputContext discardMarkedText];
[bd->InputContext invalidateCharacterCoordinates];
[bd->InputContext deactivate];
}
[g_KeyEventResponder setImePosX:data->InputPos.x imePosY:data->InputPos.y + data->InputLineHeight];
[bd->KeyEventResponder setImePosX:data->InputPos.x imePosY:data->InputPos.y + data->InputLineHeight];
};

return true;
}

void ImGui_ImplOSX_Shutdown()
{
g_FocusObserver = NULL;
ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
bd->FocusObserver = NULL;
ImGui_ImplOSX_DestroyBackendData();
}

static void ImGui_ImplOSX_UpdateMouseCursor()
{
ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
ImGuiIO& io = ImGui::GetIO();
if (io.ConfigFlags & ImGuiConfigFlags_NoMouseCursorChange)
return;
Expand All @@ -470,23 +488,23 @@ static void ImGui_ImplOSX_UpdateMouseCursor()
if (io.MouseDrawCursor || imgui_cursor == ImGuiMouseCursor_None)
{
// Hide OS mouse cursor if imgui is drawing it or if it wants no cursor
if (!g_MouseCursorHidden)
if (!bd->MouseCursorHidden)
{
g_MouseCursorHidden = true;
bd->MouseCursorHidden = true;
[NSCursor hide];
}
}
else
{
NSCursor* desired = g_MouseCursors[imgui_cursor] ?: g_MouseCursors[ImGuiMouseCursor_Arrow];
NSCursor* desired = bd->MouseCursors[imgui_cursor] ?: bd->MouseCursors[ImGuiMouseCursor_Arrow];
// -[NSCursor set] generates measureable overhead if called unconditionally.
if (desired != NSCursor.currentCursor)
{
[desired set];
}
if (g_MouseCursorHidden)
if (bd->MouseCursorHidden)
{
g_MouseCursorHidden = false;
bd->MouseCursorHidden = false;
[NSCursor unhide];
}
}
Expand Down Expand Up @@ -553,15 +571,18 @@ static void ImGui_ImplOSX_UpdateGamepads()

static void ImGui_ImplOSX_UpdateImePosWithView(NSView* view)
{
ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
ImGuiIO& io = ImGui::GetIO();
if (io.WantTextInput)
[g_KeyEventResponder updateImePosWithView:view];
[bd->KeyEventResponder updateImePosWithView:view];
}

void ImGui_ImplOSX_NewFrame(NSView* view)
{
// Setup display size
ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
ImGuiIO& io = ImGui::GetIO();

// Setup display size
if (view)
{
const float dpi = (float)[view.window backingScaleFactor];
Expand All @@ -570,14 +591,14 @@ void ImGui_ImplOSX_NewFrame(NSView* view)
}

// Setup time step
if (g_Time == 0.0)
if (bd->Time == 0.0)
{
InitHostClockPeriod();
g_Time = GetMachAbsoluteTimeInSeconds();
bd->Time = GetMachAbsoluteTimeInSeconds();
}
double current_time = GetMachAbsoluteTimeInSeconds();
io.DeltaTime = (float)(current_time - g_Time);
g_Time = current_time;
io.DeltaTime = (float)(current_time - bd->Time);
bd->Time = current_time;

ImGui_ImplOSX_UpdateMouseCursor();
ImGui_ImplOSX_UpdateGamepads();
Expand Down
2 changes: 2 additions & 0 deletions docs/CHANGELOG.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -99,6 +99,8 @@ Other Changes:
- Backends: SDL: Added support for extra mouse buttons (SDL_BUTTON_X1/SDL_BUTTON_X2). (#5125) [@sgiurgiu]
- Backends: SDL, OpenGL3: Fixes to facilitate building on AmigaOS4. (#5190) [@afxgroup]
- Backends: OSX: Monitor NSKeyUp events to catch missing keyUp for key when user press Cmd + key (#5128) [@thedmd]
- Backends: OSX, Metal: Store backend data in a per-context struct, allowing to use these backends with
multiple contexts. (#5203, #5221, #4141) [@noisewuwei]
- Examples: Emscripten+WebGPU: Fix building for latest WebGPU specs. (#3632)


Expand Down

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