ghostty/src/renderer/metal/shaders.zig
2023-11-17 21:50:53 -08:00

654 lines
23 KiB
Zig

const std = @import("std");
const Allocator = std.mem.Allocator;
const assert = std.debug.assert;
const macos = @import("macos");
const objc = @import("objc");
const math = @import("../../math.zig");
const mtl = @import("api.zig");
const log = std.log.scoped(.metal);
/// This contains the state for the shaders used by the Metal renderer.
pub const Shaders = struct {
library: objc.Object,
/// The cell shader is the shader used to render the terminal cells.
/// It is a single shader that is used for both the background and
/// foreground.
cell_pipeline: objc.Object,
/// The image shader is the shader used to render images for things
/// like the Kitty image protocol.
image_pipeline: objc.Object,
/// Custom shaders to run against the final drawable texture. This
/// can be used to apply a lot of effects. Each shader is run in sequence
/// against the output of the previous shader.
post_pipelines: []const objc.Object,
/// Initialize our shader set.
///
/// "post_shaders" is an optional list of postprocess shaders to run
/// against the final drawable texture. This is an array of shader source
/// code, not file paths.
pub fn init(
alloc: Allocator,
device: objc.Object,
post_shaders: []const [:0]const u8,
) !Shaders {
const library = try initLibrary(device);
errdefer library.msgSend(void, objc.sel("release"), .{});
const cell_pipeline = try initCellPipeline(device, library);
errdefer cell_pipeline.msgSend(void, objc.sel("release"), .{});
const image_pipeline = try initImagePipeline(device, library);
errdefer image_pipeline.msgSend(void, objc.sel("release"), .{});
const post_pipelines: []const objc.Object = initPostPipelines(
alloc,
device,
library,
post_shaders,
) catch |err| err: {
// If an error happens while building postprocess shaders we
// want to just not use any postprocess shaders since we don't
// want to block Ghostty from working.
log.warn("error initializing postprocess shaders err={}", .{err});
break :err &.{};
};
errdefer if (post_pipelines.len > 0) {
for (post_pipelines) |pipeline| pipeline.msgSend(void, objc.sel("release"), .{});
alloc.free(post_pipelines);
};
return .{
.library = library,
.cell_pipeline = cell_pipeline,
.image_pipeline = image_pipeline,
.post_pipelines = post_pipelines,
};
}
pub fn deinit(self: *Shaders, alloc: Allocator) void {
// Release our primary shaders
self.cell_pipeline.msgSend(void, objc.sel("release"), .{});
self.image_pipeline.msgSend(void, objc.sel("release"), .{});
self.library.msgSend(void, objc.sel("release"), .{});
// Release our postprocess shaders
if (self.post_pipelines.len > 0) {
for (self.post_pipelines) |pipeline| {
pipeline.msgSend(void, objc.sel("release"), .{});
}
alloc.free(self.post_pipelines);
}
}
};
/// This is a single parameter for the terminal cell shader.
pub const Cell = extern struct {
mode: Mode,
grid_pos: [2]f32,
glyph_pos: [2]u32 = .{ 0, 0 },
glyph_size: [2]u32 = .{ 0, 0 },
glyph_offset: [2]i32 = .{ 0, 0 },
color: [4]u8,
cell_width: u8,
pub const Mode = enum(u8) {
bg = 1,
fg = 2,
fg_color = 7,
strikethrough = 8,
};
};
/// Single parameter for the image shader. See shader for field details.
pub const Image = extern struct {
grid_pos: [2]f32,
cell_offset: [2]f32,
source_rect: [4]f32,
dest_size: [2]f32,
};
/// The uniforms that are passed to the terminal cell shader.
pub const Uniforms = extern struct {
/// The projection matrix for turning world coordinates to normalized.
/// This is calculated based on the size of the screen.
projection_matrix: math.Mat,
/// Size of a single cell in pixels, unscaled.
cell_size: [2]f32,
/// Metrics for underline/strikethrough
strikethrough_position: f32,
strikethrough_thickness: f32,
};
/// The uniforms used for custom postprocess shaders.
pub const PostUniforms = extern struct {
// Note: all of the explicit aligmnments are copied from the
// MSL developer reference just so that we can be sure that we got
// it all exactly right.
resolution: [3]f32 align(16),
time: f32 align(4),
time_delta: f32 align(4),
frame_rate: f32 align(4),
frame: i32 align(4),
channel_time: [4][4]f32 align(16),
channel_resolution: [4][4]f32 align(16),
mouse: [4]f32 align(16),
date: [4]f32 align(16),
sample_rate: f32 align(4),
};
/// Initialize the MTLLibrary. A MTLLibrary is a collection of shaders.
fn initLibrary(device: objc.Object) !objc.Object {
// Hardcoded since this file isn't meant to be reusable.
const data = @embedFile("../shaders/cell.metal");
const source = try macos.foundation.String.createWithBytes(
data,
.utf8,
false,
);
defer source.release();
var err: ?*anyopaque = null;
const library = device.msgSend(
objc.Object,
objc.sel("newLibraryWithSource:options:error:"),
.{
source,
@as(?*anyopaque, null),
&err,
},
);
try checkError(err);
return library;
}
/// Initialize our custom shader pipelines. The shaders argument is a
/// set of shader source code, not file paths.
fn initPostPipelines(
alloc: Allocator,
device: objc.Object,
library: objc.Object,
shaders: []const [:0]const u8,
) ![]const objc.Object {
// If we have no shaders, do nothing.
if (shaders.len == 0) return &.{};
// Keeps track of how many shaders we successfully wrote.
var i: usize = 0;
// Initialize our result set. If any error happens, we undo everything.
var pipelines = try alloc.alloc(objc.Object, shaders.len);
errdefer {
for (pipelines[0..i]) |pipeline| {
pipeline.msgSend(void, objc.sel("release"), .{});
}
alloc.free(pipelines);
}
// Build each shader. Note we don't use "0.." to build our index
// because we need to keep track of our length to clean up above.
for (shaders) |source| {
pipelines[i] = try initPostPipeline(device, library, source);
i += 1;
}
return pipelines;
}
/// Initialize a single custom shader pipeline from shader source.
fn initPostPipeline(
device: objc.Object,
library: objc.Object,
data: [:0]const u8,
) !objc.Object {
// Create our library which has the shader source
const post_library = library: {
const source = try macos.foundation.String.createWithBytes(
data,
.utf8,
false,
);
defer source.release();
var err: ?*anyopaque = null;
const post_library = device.msgSend(
objc.Object,
objc.sel("newLibraryWithSource:options:error:"),
.{ source, @as(?*anyopaque, null), &err },
);
try checkError(err);
errdefer post_library.msgSend(void, objc.sel("release"), .{});
break :library post_library;
};
defer post_library.msgSend(void, objc.sel("release"), .{});
// Get our vertex and fragment functions
const func_vert = func_vert: {
const str = try macos.foundation.String.createWithBytes(
"post_vertex",
.utf8,
false,
);
defer str.release();
const ptr = library.msgSend(?*anyopaque, objc.sel("newFunctionWithName:"), .{str});
break :func_vert objc.Object.fromId(ptr.?);
};
const func_frag = func_frag: {
const str = try macos.foundation.String.createWithBytes(
"main0",
.utf8,
false,
);
defer str.release();
const ptr = post_library.msgSend(?*anyopaque, objc.sel("newFunctionWithName:"), .{str});
break :func_frag objc.Object.fromId(ptr.?);
};
// Create our descriptor
const desc = init: {
const Class = objc.getClass("MTLRenderPipelineDescriptor").?;
const id_alloc = Class.msgSend(objc.Object, objc.sel("alloc"), .{});
const id_init = id_alloc.msgSend(objc.Object, objc.sel("init"), .{});
break :init id_init;
};
desc.setProperty("vertexFunction", func_vert);
desc.setProperty("fragmentFunction", func_frag);
// Set our color attachment
const attachments = objc.Object.fromId(desc.getProperty(?*anyopaque, "colorAttachments"));
{
const attachment = attachments.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 0)},
);
// Value is MTLPixelFormatBGRA8Unorm
attachment.setProperty("pixelFormat", @as(c_ulong, 80));
}
// Make our state
var err: ?*anyopaque = null;
const pipeline_state = device.msgSend(
objc.Object,
objc.sel("newRenderPipelineStateWithDescriptor:error:"),
.{ desc, &err },
);
try checkError(err);
return pipeline_state;
}
/// Initialize the cell render pipeline for our shader library.
fn initCellPipeline(device: objc.Object, library: objc.Object) !objc.Object {
// Get our vertex and fragment functions
const func_vert = func_vert: {
const str = try macos.foundation.String.createWithBytes(
"uber_vertex",
.utf8,
false,
);
defer str.release();
const ptr = library.msgSend(?*anyopaque, objc.sel("newFunctionWithName:"), .{str});
break :func_vert objc.Object.fromId(ptr.?);
};
const func_frag = func_frag: {
const str = try macos.foundation.String.createWithBytes(
"uber_fragment",
.utf8,
false,
);
defer str.release();
const ptr = library.msgSend(?*anyopaque, objc.sel("newFunctionWithName:"), .{str});
break :func_frag objc.Object.fromId(ptr.?);
};
// Create the vertex descriptor. The vertex descriptor describes the
// data layout of the vertex inputs. We use indexed (or "instanced")
// rendering, so this makes it so that each instance gets a single
// Cell as input.
const vertex_desc = vertex_desc: {
const desc = init: {
const Class = objc.getClass("MTLVertexDescriptor").?;
const id_alloc = Class.msgSend(objc.Object, objc.sel("alloc"), .{});
const id_init = id_alloc.msgSend(objc.Object, objc.sel("init"), .{});
break :init id_init;
};
// Our attributes are the fields of the input
const attrs = objc.Object.fromId(desc.getProperty(?*anyopaque, "attributes"));
{
const attr = attrs.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 0)},
);
attr.setProperty("format", @intFromEnum(mtl.MTLVertexFormat.uchar));
attr.setProperty("offset", @as(c_ulong, @offsetOf(Cell, "mode")));
attr.setProperty("bufferIndex", @as(c_ulong, 0));
}
{
const attr = attrs.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 1)},
);
attr.setProperty("format", @intFromEnum(mtl.MTLVertexFormat.float2));
attr.setProperty("offset", @as(c_ulong, @offsetOf(Cell, "grid_pos")));
attr.setProperty("bufferIndex", @as(c_ulong, 0));
}
{
const attr = attrs.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 2)},
);
attr.setProperty("format", @intFromEnum(mtl.MTLVertexFormat.uint2));
attr.setProperty("offset", @as(c_ulong, @offsetOf(Cell, "glyph_pos")));
attr.setProperty("bufferIndex", @as(c_ulong, 0));
}
{
const attr = attrs.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 3)},
);
attr.setProperty("format", @intFromEnum(mtl.MTLVertexFormat.uint2));
attr.setProperty("offset", @as(c_ulong, @offsetOf(Cell, "glyph_size")));
attr.setProperty("bufferIndex", @as(c_ulong, 0));
}
{
const attr = attrs.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 4)},
);
attr.setProperty("format", @intFromEnum(mtl.MTLVertexFormat.int2));
attr.setProperty("offset", @as(c_ulong, @offsetOf(Cell, "glyph_offset")));
attr.setProperty("bufferIndex", @as(c_ulong, 0));
}
{
const attr = attrs.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 5)},
);
attr.setProperty("format", @intFromEnum(mtl.MTLVertexFormat.uchar4));
attr.setProperty("offset", @as(c_ulong, @offsetOf(Cell, "color")));
attr.setProperty("bufferIndex", @as(c_ulong, 0));
}
{
const attr = attrs.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 6)},
);
attr.setProperty("format", @intFromEnum(mtl.MTLVertexFormat.uchar));
attr.setProperty("offset", @as(c_ulong, @offsetOf(Cell, "cell_width")));
attr.setProperty("bufferIndex", @as(c_ulong, 0));
}
// The layout describes how and when we fetch the next vertex input.
const layouts = objc.Object.fromId(desc.getProperty(?*anyopaque, "layouts"));
{
const layout = layouts.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 0)},
);
// Access each Cell per instance, not per vertex.
layout.setProperty("stepFunction", @intFromEnum(mtl.MTLVertexStepFunction.per_instance));
layout.setProperty("stride", @as(c_ulong, @sizeOf(Cell)));
}
break :vertex_desc desc;
};
defer vertex_desc.msgSend(void, objc.sel("release"), .{});
// Create our descriptor
const desc = init: {
const Class = objc.getClass("MTLRenderPipelineDescriptor").?;
const id_alloc = Class.msgSend(objc.Object, objc.sel("alloc"), .{});
const id_init = id_alloc.msgSend(objc.Object, objc.sel("init"), .{});
break :init id_init;
};
defer desc.msgSend(void, objc.sel("release"), .{});
// Set our properties
desc.setProperty("vertexFunction", func_vert);
desc.setProperty("fragmentFunction", func_frag);
desc.setProperty("vertexDescriptor", vertex_desc);
// Set our color attachment
const attachments = objc.Object.fromId(desc.getProperty(?*anyopaque, "colorAttachments"));
{
const attachment = attachments.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 0)},
);
// Value is MTLPixelFormatBGRA8Unorm
attachment.setProperty("pixelFormat", @as(c_ulong, 80));
// Blending. This is required so that our text we render on top
// of our drawable properly blends into the bg.
attachment.setProperty("blendingEnabled", true);
attachment.setProperty("rgbBlendOperation", @intFromEnum(mtl.MTLBlendOperation.add));
attachment.setProperty("alphaBlendOperation", @intFromEnum(mtl.MTLBlendOperation.add));
attachment.setProperty("sourceRGBBlendFactor", @intFromEnum(mtl.MTLBlendFactor.one));
attachment.setProperty("sourceAlphaBlendFactor", @intFromEnum(mtl.MTLBlendFactor.one));
attachment.setProperty("destinationRGBBlendFactor", @intFromEnum(mtl.MTLBlendFactor.one_minus_source_alpha));
attachment.setProperty("destinationAlphaBlendFactor", @intFromEnum(mtl.MTLBlendFactor.one_minus_source_alpha));
}
// Make our state
var err: ?*anyopaque = null;
const pipeline_state = device.msgSend(
objc.Object,
objc.sel("newRenderPipelineStateWithDescriptor:error:"),
.{ desc, &err },
);
try checkError(err);
errdefer pipeline_state.msgSend(void, objc.sel("release"), .{});
return pipeline_state;
}
/// Initialize the image render pipeline for our shader library.
fn initImagePipeline(device: objc.Object, library: objc.Object) !objc.Object {
// Get our vertex and fragment functions
const func_vert = func_vert: {
const str = try macos.foundation.String.createWithBytes(
"image_vertex",
.utf8,
false,
);
defer str.release();
const ptr = library.msgSend(?*anyopaque, objc.sel("newFunctionWithName:"), .{str});
break :func_vert objc.Object.fromId(ptr.?);
};
const func_frag = func_frag: {
const str = try macos.foundation.String.createWithBytes(
"image_fragment",
.utf8,
false,
);
defer str.release();
const ptr = library.msgSend(?*anyopaque, objc.sel("newFunctionWithName:"), .{str});
break :func_frag objc.Object.fromId(ptr.?);
};
// Create the vertex descriptor. The vertex descriptor describes the
// data layout of the vertex inputs. We use indexed (or "instanced")
// rendering, so this makes it so that each instance gets a single
// Image as input.
const vertex_desc = vertex_desc: {
const desc = init: {
const Class = objc.getClass("MTLVertexDescriptor").?;
const id_alloc = Class.msgSend(objc.Object, objc.sel("alloc"), .{});
const id_init = id_alloc.msgSend(objc.Object, objc.sel("init"), .{});
break :init id_init;
};
// Our attributes are the fields of the input
const attrs = objc.Object.fromId(desc.getProperty(?*anyopaque, "attributes"));
{
const attr = attrs.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 1)},
);
attr.setProperty("format", @intFromEnum(mtl.MTLVertexFormat.float2));
attr.setProperty("offset", @as(c_ulong, @offsetOf(Image, "grid_pos")));
attr.setProperty("bufferIndex", @as(c_ulong, 0));
}
{
const attr = attrs.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 2)},
);
attr.setProperty("format", @intFromEnum(mtl.MTLVertexFormat.float2));
attr.setProperty("offset", @as(c_ulong, @offsetOf(Image, "cell_offset")));
attr.setProperty("bufferIndex", @as(c_ulong, 0));
}
{
const attr = attrs.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 3)},
);
attr.setProperty("format", @intFromEnum(mtl.MTLVertexFormat.float4));
attr.setProperty("offset", @as(c_ulong, @offsetOf(Image, "source_rect")));
attr.setProperty("bufferIndex", @as(c_ulong, 0));
}
{
const attr = attrs.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 4)},
);
attr.setProperty("format", @intFromEnum(mtl.MTLVertexFormat.float2));
attr.setProperty("offset", @as(c_ulong, @offsetOf(Image, "dest_size")));
attr.setProperty("bufferIndex", @as(c_ulong, 0));
}
// The layout describes how and when we fetch the next vertex input.
const layouts = objc.Object.fromId(desc.getProperty(?*anyopaque, "layouts"));
{
const layout = layouts.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 0)},
);
// Access each Image per instance, not per vertex.
layout.setProperty("stepFunction", @intFromEnum(mtl.MTLVertexStepFunction.per_instance));
layout.setProperty("stride", @as(c_ulong, @sizeOf(Image)));
}
break :vertex_desc desc;
};
// Create our descriptor
const desc = init: {
const Class = objc.getClass("MTLRenderPipelineDescriptor").?;
const id_alloc = Class.msgSend(objc.Object, objc.sel("alloc"), .{});
const id_init = id_alloc.msgSend(objc.Object, objc.sel("init"), .{});
break :init id_init;
};
// Set our properties
desc.setProperty("vertexFunction", func_vert);
desc.setProperty("fragmentFunction", func_frag);
desc.setProperty("vertexDescriptor", vertex_desc);
// Set our color attachment
const attachments = objc.Object.fromId(desc.getProperty(?*anyopaque, "colorAttachments"));
{
const attachment = attachments.msgSend(
objc.Object,
objc.sel("objectAtIndexedSubscript:"),
.{@as(c_ulong, 0)},
);
// Value is MTLPixelFormatBGRA8Unorm
attachment.setProperty("pixelFormat", @as(c_ulong, 80));
// Blending. This is required so that our text we render on top
// of our drawable properly blends into the bg.
attachment.setProperty("blendingEnabled", true);
attachment.setProperty("rgbBlendOperation", @intFromEnum(mtl.MTLBlendOperation.add));
attachment.setProperty("alphaBlendOperation", @intFromEnum(mtl.MTLBlendOperation.add));
attachment.setProperty("sourceRGBBlendFactor", @intFromEnum(mtl.MTLBlendFactor.one));
attachment.setProperty("sourceAlphaBlendFactor", @intFromEnum(mtl.MTLBlendFactor.one));
attachment.setProperty("destinationRGBBlendFactor", @intFromEnum(mtl.MTLBlendFactor.one_minus_source_alpha));
attachment.setProperty("destinationAlphaBlendFactor", @intFromEnum(mtl.MTLBlendFactor.one_minus_source_alpha));
}
// Make our state
var err: ?*anyopaque = null;
const pipeline_state = device.msgSend(
objc.Object,
objc.sel("newRenderPipelineStateWithDescriptor:error:"),
.{ desc, &err },
);
try checkError(err);
return pipeline_state;
}
fn checkError(err_: ?*anyopaque) !void {
const nserr = objc.Object.fromId(err_ orelse return);
const str = @as(
*macos.foundation.String,
@ptrCast(nserr.getProperty(?*anyopaque, "localizedDescription").?),
);
log.err("metal error={s}", .{str.cstringPtr(.ascii).?});
return error.MetalFailed;
}
// Intel macOS 13 doesn't like it when any field in a vertex buffer is not
// aligned on the alignment of the struct. I don't understand it, I think
// this must be some macOS 13 Metal GPU driver bug because it doesn't matter
// on macOS 12 or Apple Silicon macOS 13.
//
// To be safe, we put this test in here.
test "Cell offsets" {
const testing = std.testing;
const alignment = @alignOf(Cell);
inline for (@typeInfo(Cell).Struct.fields) |field| {
const offset = @offsetOf(Cell, field.name);
try testing.expectEqual(0, @mod(offset, alignment));
}
}