// dear imgui: Renderer Backend for Metal // This needs to be used along with a Platform Backend (e.g. OSX) // Implemented features: // [X] Renderer: User texture binding. Use 'MTLTexture' as ImTextureID. Read the FAQ about ImTextureID! // [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices. // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this. // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need. // If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp. // Read online: https://github.com/ocornut/imgui/tree/master/docs // CHANGELOG // (minor and older changes stripped away, please see git history for details) // 2022-08-23: Metal: Update deprecated property 'sampleCount'->'rasterSampleCount'. // 2022-07-05: Metal: Add dispatch synchronization. // 2022-06-30: Metal: Use __bridge for ARC based systems. // 2022-06-01: Metal: Fixed null dereference on exit inside command buffer completion handler. // 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) // 2021-05-19: Metal: Replaced direct access to ImDrawCmd::TextureId with a call to ImDrawCmd::GetTexID(). (will become a requirement) // 2021-02-18: Metal: Change blending equation to preserve alpha in output buffer. // 2021-01-25: Metal: Fixed texture storage mode when building on Mac Catalyst. // 2019-05-29: Metal: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_RendererHasVtxOffset flag. // 2019-04-30: Metal: Added support for special ImDrawCallback_ResetRenderState callback to reset render state. // 2019-02-11: Metal: Projecting clipping rectangles correctly using draw_data->FramebufferScale to allow multi-viewports for retina display. // 2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window. // 2018-07-05: Metal: Added new Metal backend implementation. #include "imgui.h" #include "imgui_impl_metal.h" #import <time.h> #import <Metal/Metal.h> #pragma mark - Support classes // A wrapper around a MTLBuffer object that knows the last time it was reused @interface MetalBuffer : NSObject @property (nonatomic, strong) id<MTLBuffer> buffer; @property (nonatomic, assign) double lastReuseTime; - (instancetype)initWithBuffer:(id<MTLBuffer>)buffer; @end // An object that encapsulates the data necessary to uniquely identify a // render pipeline state. These are used as cache keys. @interface FramebufferDescriptor : NSObject<NSCopying> @property (nonatomic, assign) unsigned long sampleCount; @property (nonatomic, assign) MTLPixelFormat colorPixelFormat; @property (nonatomic, assign) MTLPixelFormat depthPixelFormat; @property (nonatomic, assign) MTLPixelFormat stencilPixelFormat; - (instancetype)initWithRenderPassDescriptor:(MTLRenderPassDescriptor*)renderPassDescriptor; @end // A singleton that stores long-lived objects that are needed by the Metal // 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 @property (nonatomic, strong, nullable) id<MTLTexture> fontTexture; @property (nonatomic, strong) NSMutableArray<MetalBuffer*>* bufferCache; @property (nonatomic, assign) double lastBufferCachePurge; - (MetalBuffer*)dequeueReusableBufferOfLength:(NSUInteger)length device:(id<MTLDevice>)device; - (id<MTLRenderPipelineState>)renderPipelineStateForFramebufferDescriptor:(FramebufferDescriptor*)descriptor device:(id<MTLDevice>)device; @end 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 : nullptr; } static void ImGui_ImplMetal_DestroyBackendData(){ IM_DELETE(ImGui_ImplMetal_GetBackendData()); } static inline CFTimeInterval GetMachAbsoluteTimeInSeconds() { return (CFTimeInterval)(double)(clock_gettime_nsec_np(CLOCK_UPTIME_RAW) / 1e9); } #ifdef IMGUI_IMPL_METAL_CPP #pragma mark - Dear ImGui Metal C++ Backend API bool ImGui_ImplMetal_Init(MTL::Device* device) { return ImGui_ImplMetal_Init((__bridge id<MTLDevice>)(device)); } void ImGui_ImplMetal_NewFrame(MTL::RenderPassDescriptor* renderPassDescriptor) { ImGui_ImplMetal_NewFrame((__bridge MTLRenderPassDescriptor*)(renderPassDescriptor)); } void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data, MTL::CommandBuffer* commandBuffer, MTL::RenderCommandEncoder* commandEncoder) { ImGui_ImplMetal_RenderDrawData(draw_data, (__bridge id<MTLCommandBuffer>)(commandBuffer), (__bridge id<MTLRenderCommandEncoder>)(commandEncoder)); } bool ImGui_ImplMetal_CreateFontsTexture(MTL::Device* device) { return ImGui_ImplMetal_CreateFontsTexture((__bridge id<MTLDevice>)(device)); } bool ImGui_ImplMetal_CreateDeviceObjects(MTL::Device* device) { return ImGui_ImplMetal_CreateDeviceObjects((__bridge id<MTLDevice>)(device)); } #endif // #ifdef IMGUI_IMPL_METAL_CPP #pragma mark - Dear ImGui Metal Backend API 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. 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) { 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]; if (bd->SharedMetalContext.depthStencilState == nil) ImGui_ImplMetal_CreateDeviceObjects(bd->SharedMetalContext.device); } static void ImGui_ImplMetal_SetupRenderState(ImDrawData* drawData, id<MTLCommandBuffer> commandBuffer, id<MTLRenderCommandEncoder> commandEncoder, id<MTLRenderPipelineState> renderPipelineState, MetalBuffer* vertexBuffer, size_t vertexBufferOffset) { IM_UNUSED(commandBuffer); ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData(); [commandEncoder setCullMode:MTLCullModeNone]; [commandEncoder setDepthStencilState:bd->SharedMetalContext.depthStencilState]; // Setup viewport, orthographic projection matrix // Our visible imgui space lies from draw_data->DisplayPos (top left) to // draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is typically (0,0) for single viewport apps. MTLViewport viewport = { .originX = 0.0, .originY = 0.0, .width = (double)(drawData->DisplaySize.x * drawData->FramebufferScale.x), .height = (double)(drawData->DisplaySize.y * drawData->FramebufferScale.y), .znear = 0.0, .zfar = 1.0 }; [commandEncoder setViewport:viewport]; float L = drawData->DisplayPos.x; float R = drawData->DisplayPos.x + drawData->DisplaySize.x; float T = drawData->DisplayPos.y; float B = drawData->DisplayPos.y + drawData->DisplaySize.y; float N = (float)viewport.znear; float F = (float)viewport.zfar; const float ortho_projection[4][4] = { { 2.0f/(R-L), 0.0f, 0.0f, 0.0f }, { 0.0f, 2.0f/(T-B), 0.0f, 0.0f }, { 0.0f, 0.0f, 1/(F-N), 0.0f }, { (R+L)/(L-R), (T+B)/(B-T), N/(F-N), 1.0f }, }; [commandEncoder setVertexBytes:&ortho_projection length:sizeof(ortho_projection) atIndex:1]; [commandEncoder setRenderPipelineState:renderPipelineState]; [commandEncoder setVertexBuffer:vertexBuffer.buffer offset:0 atIndex:0]; [commandEncoder setVertexBufferOffset:vertexBufferOffset atIndex:0]; } // Metal Render function. void ImGui_ImplMetal_RenderDrawData(ImDrawData* drawData, id<MTLCommandBuffer> commandBuffer, id<MTLRenderCommandEncoder> commandEncoder) { ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData(); MetalContext* ctx = bd->SharedMetalContext; // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates) int fb_width = (int)(drawData->DisplaySize.x * drawData->FramebufferScale.x); int fb_height = (int)(drawData->DisplaySize.y * drawData->FramebufferScale.y); if (fb_width <= 0 || fb_height <= 0 || drawData->CmdListsCount == 0) return; // Try to retrieve a render pipeline state that is compatible with the framebuffer config for this frame // The hit rate for this cache should be very near 100%. id<MTLRenderPipelineState> renderPipelineState = ctx.renderPipelineStateCache[ctx.framebufferDescriptor]; if (renderPipelineState == nil) { // No luck; make a new render pipeline state renderPipelineState = [ctx renderPipelineStateForFramebufferDescriptor:ctx.framebufferDescriptor device:commandBuffer.device]; // Cache render pipeline state for later reuse ctx.renderPipelineStateCache[ctx.framebufferDescriptor] = renderPipelineState; } size_t vertexBufferLength = (size_t)drawData->TotalVtxCount * sizeof(ImDrawVert); size_t indexBufferLength = (size_t)drawData->TotalIdxCount * sizeof(ImDrawIdx); MetalBuffer* vertexBuffer = [ctx dequeueReusableBufferOfLength:vertexBufferLength device:commandBuffer.device]; MetalBuffer* indexBuffer = [ctx dequeueReusableBufferOfLength:indexBufferLength device:commandBuffer.device]; ImGui_ImplMetal_SetupRenderState(drawData, commandBuffer, commandEncoder, renderPipelineState, vertexBuffer, 0); // Will project scissor/clipping rectangles into framebuffer space ImVec2 clip_off = drawData->DisplayPos; // (0,0) unless using multi-viewports ImVec2 clip_scale = drawData->FramebufferScale; // (1,1) unless using retina display which are often (2,2) // Render command lists size_t vertexBufferOffset = 0; size_t indexBufferOffset = 0; for (int n = 0; n < drawData->CmdListsCount; n++) { const ImDrawList* cmd_list = drawData->CmdLists[n]; memcpy((char*)vertexBuffer.buffer.contents + vertexBufferOffset, cmd_list->VtxBuffer.Data, (size_t)cmd_list->VtxBuffer.Size * sizeof(ImDrawVert)); memcpy((char*)indexBuffer.buffer.contents + indexBufferOffset, cmd_list->IdxBuffer.Data, (size_t)cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx)); for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++) { const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i]; if (pcmd->UserCallback) { // User callback, registered via ImDrawList::AddCallback() // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.) if (pcmd->UserCallback == ImDrawCallback_ResetRenderState) ImGui_ImplMetal_SetupRenderState(drawData, commandBuffer, commandEncoder, renderPipelineState, vertexBuffer, vertexBufferOffset); else pcmd->UserCallback(cmd_list, pcmd); } else { // Project scissor/clipping rectangles into framebuffer space ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y); ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y); // Clamp to viewport as setScissorRect() won't accept values that are off bounds if (clip_min.x < 0.0f) { clip_min.x = 0.0f; } if (clip_min.y < 0.0f) { clip_min.y = 0.0f; } if (clip_max.x > fb_width) { clip_max.x = (float)fb_width; } if (clip_max.y > fb_height) { clip_max.y = (float)fb_height; } if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y) continue; if (pcmd->ElemCount == 0) // drawIndexedPrimitives() validation doesn't accept this continue; // Apply scissor/clipping rectangle MTLScissorRect scissorRect = { .x = NSUInteger(clip_min.x), .y = NSUInteger(clip_min.y), .width = NSUInteger(clip_max.x - clip_min.x), .height = NSUInteger(clip_max.y - clip_min.y) }; [commandEncoder setScissorRect:scissorRect]; // Bind texture, Draw if (ImTextureID tex_id = pcmd->GetTexID()) [commandEncoder setFragmentTexture:(__bridge id<MTLTexture>)(tex_id) atIndex:0]; [commandEncoder setVertexBufferOffset:(vertexBufferOffset + pcmd->VtxOffset * sizeof(ImDrawVert)) atIndex:0]; [commandEncoder drawIndexedPrimitives:MTLPrimitiveTypeTriangle indexCount:pcmd->ElemCount indexType:sizeof(ImDrawIdx) == 2 ? MTLIndexTypeUInt16 : MTLIndexTypeUInt32 indexBuffer:indexBuffer.buffer indexBufferOffset:indexBufferOffset + pcmd->IdxOffset * sizeof(ImDrawIdx)]; } } vertexBufferOffset += (size_t)cmd_list->VtxBuffer.Size * sizeof(ImDrawVert); indexBufferOffset += (size_t)cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx); } [commandBuffer addCompletedHandler:^(id<MTLCommandBuffer>) { dispatch_async(dispatch_get_main_queue(), ^{ ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData(); if (bd != nullptr) { @synchronized(bd->SharedMetalContext.bufferCache) { [bd->SharedMetalContext.bufferCache addObject:vertexBuffer]; [bd->SharedMetalContext.bufferCache addObject:indexBuffer]; } } }); }]; } bool ImGui_ImplMetal_CreateFontsTexture(id<MTLDevice> device) { ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData(); ImGuiIO& io = ImGui::GetIO(); // We are retrieving and uploading the font atlas as a 4-channels RGBA texture here. // In theory we could call GetTexDataAsAlpha8() and upload a 1-channel texture to save on memory access bandwidth. // However, using a shader designed for 1-channel texture would make it less obvious to use the ImTextureID facility to render users own textures. // You can make that change in your implementation. unsigned char* pixels; int width, height; io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height); MTLTextureDescriptor* textureDescriptor = [MTLTextureDescriptor texture2DDescriptorWithPixelFormat:MTLPixelFormatRGBA8Unorm width:(NSUInteger)width height:(NSUInteger)height mipmapped:NO]; textureDescriptor.usage = MTLTextureUsageShaderRead; #if TARGET_OS_OSX || TARGET_OS_MACCATALYST textureDescriptor.storageMode = MTLStorageModeManaged; #else textureDescriptor.storageMode = MTLStorageModeShared; #endif id <MTLTexture> texture = [device newTextureWithDescriptor:textureDescriptor]; [texture replaceRegion:MTLRegionMake2D(0, 0, (NSUInteger)width, (NSUInteger)height) mipmapLevel:0 withBytes:pixels bytesPerRow:(NSUInteger)width * 4]; bd->SharedMetalContext.fontTexture = texture; io.Fonts->SetTexID((__bridge void*)bd->SharedMetalContext.fontTexture); // ImTextureID == void* return (bd->SharedMetalContext.fontTexture != nil); } void ImGui_ImplMetal_DestroyFontsTexture() { ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData(); ImGuiIO& io = ImGui::GetIO(); bd->SharedMetalContext.fontTexture = nil; io.Fonts->SetTexID(nullptr); } bool ImGui_ImplMetal_CreateDeviceObjects(id<MTLDevice> device) { ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData(); MTLDepthStencilDescriptor* depthStencilDescriptor = [[MTLDepthStencilDescriptor alloc] init]; depthStencilDescriptor.depthWriteEnabled = NO; depthStencilDescriptor.depthCompareFunction = MTLCompareFunctionAlways; bd->SharedMetalContext.depthStencilState = [device newDepthStencilStateWithDescriptor:depthStencilDescriptor]; ImGui_ImplMetal_CreateFontsTexture(device); return true; } void ImGui_ImplMetal_DestroyDeviceObjects() { ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData(); ImGui_ImplMetal_DestroyFontsTexture(); [bd->SharedMetalContext.renderPipelineStateCache removeAllObjects]; } #pragma mark - MetalBuffer implementation @implementation MetalBuffer - (instancetype)initWithBuffer:(id<MTLBuffer>)buffer { if ((self = [super init])) { _buffer = buffer; _lastReuseTime = GetMachAbsoluteTimeInSeconds(); } return self; } @end #pragma mark - FramebufferDescriptor implementation @implementation FramebufferDescriptor - (instancetype)initWithRenderPassDescriptor:(MTLRenderPassDescriptor*)renderPassDescriptor { if ((self = [super init])) { _sampleCount = renderPassDescriptor.colorAttachments[0].texture.sampleCount; _colorPixelFormat = renderPassDescriptor.colorAttachments[0].texture.pixelFormat; _depthPixelFormat = renderPassDescriptor.depthAttachment.texture.pixelFormat; _stencilPixelFormat = renderPassDescriptor.stencilAttachment.texture.pixelFormat; } return self; } - (nonnull id)copyWithZone:(nullable NSZone*)zone { FramebufferDescriptor* copy = [[FramebufferDescriptor allocWithZone:zone] init]; copy.sampleCount = self.sampleCount; copy.colorPixelFormat = self.colorPixelFormat; copy.depthPixelFormat = self.depthPixelFormat; copy.stencilPixelFormat = self.stencilPixelFormat; return copy; } - (NSUInteger)hash { NSUInteger sc = _sampleCount & 0x3; NSUInteger cf = _colorPixelFormat & 0x3FF; NSUInteger df = _depthPixelFormat & 0x3FF; NSUInteger sf = _stencilPixelFormat & 0x3FF; NSUInteger hash = (sf << 22) | (df << 12) | (cf << 2) | sc; return hash; } - (BOOL)isEqual:(id)object { FramebufferDescriptor* other = object; if (![other isKindOfClass:[FramebufferDescriptor class]]) return NO; return other.sampleCount == self.sampleCount && other.colorPixelFormat == self.colorPixelFormat && other.depthPixelFormat == self.depthPixelFormat && other.stencilPixelFormat == self.stencilPixelFormat; } @end #pragma mark - MetalContext implementation @implementation MetalContext - (instancetype)init { if ((self = [super init])) { self.renderPipelineStateCache = [NSMutableDictionary dictionary]; self.bufferCache = [NSMutableArray array]; _lastBufferCachePurge = GetMachAbsoluteTimeInSeconds(); } return self; } - (MetalBuffer*)dequeueReusableBufferOfLength:(NSUInteger)length device:(id<MTLDevice>)device { uint64_t now = GetMachAbsoluteTimeInSeconds(); @synchronized(self.bufferCache) { // Purge old buffers that haven't been useful for a while if (now - self.lastBufferCachePurge > 1.0) { NSMutableArray* survivors = [NSMutableArray array]; for (MetalBuffer* candidate in self.bufferCache) if (candidate.lastReuseTime > self.lastBufferCachePurge) [survivors addObject:candidate]; self.bufferCache = [survivors mutableCopy]; self.lastBufferCachePurge = now; } // See if we have a buffer we can reuse MetalBuffer* bestCandidate = nil; for (MetalBuffer* candidate in self.bufferCache) if (candidate.buffer.length >= length && (bestCandidate == nil || bestCandidate.lastReuseTime > candidate.lastReuseTime)) bestCandidate = candidate; if (bestCandidate != nil) { [self.bufferCache removeObject:bestCandidate]; bestCandidate.lastReuseTime = now; return bestCandidate; } } // No luck; make a new buffer id<MTLBuffer> backing = [device newBufferWithLength:length options:MTLResourceStorageModeShared]; return [[MetalBuffer alloc] initWithBuffer:backing]; } // Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling. - (id<MTLRenderPipelineState>)renderPipelineStateForFramebufferDescriptor:(FramebufferDescriptor*)descriptor device:(id<MTLDevice>)device { NSError* error = nil; NSString* shaderSource = @"" "#include <metal_stdlib>\n" "using namespace metal;\n" "\n" "struct Uniforms {\n" " float4x4 projectionMatrix;\n" "};\n" "\n" "struct VertexIn {\n" " float2 position [[attribute(0)]];\n" " float2 texCoords [[attribute(1)]];\n" " uchar4 color [[attribute(2)]];\n" "};\n" "\n" "struct VertexOut {\n" " float4 position [[position]];\n" " float2 texCoords;\n" " float4 color;\n" "};\n" "\n" "vertex VertexOut vertex_main(VertexIn in [[stage_in]],\n" " constant Uniforms &uniforms [[buffer(1)]]) {\n" " VertexOut out;\n" " out.position = uniforms.projectionMatrix * float4(in.position, 0, 1);\n" " out.texCoords = in.texCoords;\n" " out.color = float4(in.color) / float4(255.0);\n" " return out;\n" "}\n" "\n" "fragment half4 fragment_main(VertexOut in [[stage_in]],\n" " texture2d<half, access::sample> texture [[texture(0)]]) {\n" " constexpr sampler linearSampler(coord::normalized, min_filter::linear, mag_filter::linear, mip_filter::linear);\n" " half4 texColor = texture.sample(linearSampler, in.texCoords);\n" " return half4(in.color) * texColor;\n" "}\n"; id<MTLLibrary> library = [device newLibraryWithSource:shaderSource options:nil error:&error]; if (library == nil) { NSLog(@"Error: failed to create Metal library: %@", error); return nil; } id<MTLFunction> vertexFunction = [library newFunctionWithName:@"vertex_main"]; id<MTLFunction> fragmentFunction = [library newFunctionWithName:@"fragment_main"]; if (vertexFunction == nil || fragmentFunction == nil) { NSLog(@"Error: failed to find Metal shader functions in library: %@", error); return nil; } MTLVertexDescriptor* vertexDescriptor = [MTLVertexDescriptor vertexDescriptor]; vertexDescriptor.attributes[0].offset = IM_OFFSETOF(ImDrawVert, pos); vertexDescriptor.attributes[0].format = MTLVertexFormatFloat2; // position vertexDescriptor.attributes[0].bufferIndex = 0; vertexDescriptor.attributes[1].offset = IM_OFFSETOF(ImDrawVert, uv); vertexDescriptor.attributes[1].format = MTLVertexFormatFloat2; // texCoords vertexDescriptor.attributes[1].bufferIndex = 0; vertexDescriptor.attributes[2].offset = IM_OFFSETOF(ImDrawVert, col); vertexDescriptor.attributes[2].format = MTLVertexFormatUChar4; // color vertexDescriptor.attributes[2].bufferIndex = 0; vertexDescriptor.layouts[0].stepRate = 1; vertexDescriptor.layouts[0].stepFunction = MTLVertexStepFunctionPerVertex; vertexDescriptor.layouts[0].stride = sizeof(ImDrawVert); MTLRenderPipelineDescriptor* pipelineDescriptor = [[MTLRenderPipelineDescriptor alloc] init]; pipelineDescriptor.vertexFunction = vertexFunction; pipelineDescriptor.fragmentFunction = fragmentFunction; pipelineDescriptor.vertexDescriptor = vertexDescriptor; pipelineDescriptor.rasterSampleCount = self.framebufferDescriptor.sampleCount; pipelineDescriptor.colorAttachments[0].pixelFormat = self.framebufferDescriptor.colorPixelFormat; pipelineDescriptor.colorAttachments[0].blendingEnabled = YES; pipelineDescriptor.colorAttachments[0].rgbBlendOperation = MTLBlendOperationAdd; pipelineDescriptor.colorAttachments[0].sourceRGBBlendFactor = MTLBlendFactorSourceAlpha; pipelineDescriptor.colorAttachments[0].destinationRGBBlendFactor = MTLBlendFactorOneMinusSourceAlpha; pipelineDescriptor.colorAttachments[0].alphaBlendOperation = MTLBlendOperationAdd; pipelineDescriptor.colorAttachments[0].sourceAlphaBlendFactor = MTLBlendFactorOne; pipelineDescriptor.colorAttachments[0].destinationAlphaBlendFactor = MTLBlendFactorOneMinusSourceAlpha; pipelineDescriptor.depthAttachmentPixelFormat = self.framebufferDescriptor.depthPixelFormat; pipelineDescriptor.stencilAttachmentPixelFormat = self.framebufferDescriptor.stencilPixelFormat; id<MTLRenderPipelineState> renderPipelineState = [device newRenderPipelineStateWithDescriptor:pipelineDescriptor error:&error]; if (error != nil) NSLog(@"Error: failed to create Metal pipeline state: %@", error); return renderPipelineState; } @end