// 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.
// Learn about Dear ImGui:
// - FAQ https://dearimgui.com/faq
// - Getting Started https://dearimgui.com/getting-started
// - Documentation https://dearimgui.com/docs (same as your local docs/ folder).
// - Introduction, links and more at the top of imgui.cpp
// 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"
#ifndef IMGUI_DISABLE
#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_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)
{
ImGuiIO& io = ImGui::GetIO();
IMGUI_CHECKVERSION();
IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
ImGui_ImplMetal_Data* bd = IM_NEW(ImGui_ImplMetal_Data)();
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_Data* bd = ImGui_ImplMetal_GetBackendData();
IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
ImGui_ImplMetal_DestroyDeviceObjects();
ImGui_ImplMetal_DestroyBackendData();
ImGuiIO& io = ImGui::GetIO();
io.BackendRendererName = nullptr;
io.BackendRendererUserData = nullptr;
io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
}
void ImGui_ImplMetal_NewFrame(MTLRenderPassDescriptor* renderPassDescriptor)
{
ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
IM_ASSERT(bd != nil && "Context or backend not initialized! 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(0);
}
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 = offsetof(ImDrawVert, pos);
vertexDescriptor.attributes[0].format = MTLVertexFormatFloat2; // position
vertexDescriptor.attributes[0].bufferIndex = 0;
vertexDescriptor.attributes[1].offset = offsetof(ImDrawVert, uv);
vertexDescriptor.attributes[1].format = MTLVertexFormatFloat2; // texCoords
vertexDescriptor.attributes[1].bufferIndex = 0;
vertexDescriptor.attributes[2].offset = 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
//-----------------------------------------------------------------------------
#endif // #ifndef IMGUI_DISABLE
