From ac58b7d33eff8e6748b6bb1c296f18cc6ae6d5a6 Mon Sep 17 00:00:00 2001
From: Ali Chraghi <alichraghi@proton.me>
Date: Fri, 2 Feb 2024 17:48:40 +0330
Subject: [PATCH] std: add gpu namespace

---
 lib/std/gpu.zig | 192 ++++++++++++++++++++++++++++++++++++++++++++++++
 lib/std/std.zig |   3 +
 2 files changed, 195 insertions(+)
 create mode 100644 lib/std/gpu.zig

diff --git a/lib/std/gpu.zig b/lib/std/gpu.zig
new file mode 100644
index 000000000000..0c998c86c222
--- /dev/null
+++ b/lib/std/gpu.zig
@@ -0,0 +1,192 @@
+const std = @import("std.zig");
+const comptimePrint = std.fmt.comptimePrint;
+
+/// Will make `ptr` contain the location of the current invocation within the
+/// global workgroup. Each component is equal to the index of the local workgroup
+/// multiplied by the size of the local workgroup plus `localInvocationId`.
+/// `ptr` must be a reference to variable or struct field.
+pub fn globalInvocationId(comptime ptr: *addrspace(.input) @Vector(3, u32)) void {
+    asm volatile (
+        \\OpDecorate %ptr BuiltIn GlobalInvocationId
+        :
+        : [ptr] "" (ptr),
+    );
+}
+
+/// Will make that variable contain the location of the current cluster
+/// culling, task, mesh, or compute shader invocation within the local
+/// workgroup. Each component ranges from zero through to the size of the
+/// workgroup in that dimension minus one.
+/// `ptr` must be a reference to variable or struct field.
+pub fn localInvocationId(comptime ptr: *addrspace(.input) @Vector(3, u32)) void {
+    asm volatile (
+        \\OpDecorate %ptr BuiltIn LocalInvocationId
+        :
+        : [ptr] "" (ptr),
+    );
+}
+
+/// Output vertex position from a `Vertex` entrypoint
+/// `ptr` must be a reference to variable or struct field.
+pub fn position(comptime ptr: *addrspace(.output) @Vector(4, f32)) void {
+    asm volatile (
+        \\OpDecorate %ptr BuiltIn Position
+        :
+        : [ptr] "" (ptr),
+    );
+}
+
+/// Will make `ptr` contain the index of the vertex that is
+/// being processed by the current vertex shader invocation.
+/// `ptr` must be a reference to variable or struct field.
+pub fn vertexIndex(comptime ptr: *addrspace(.input) u32) void {
+    asm volatile (
+        \\OpDecorate %ptr BuiltIn VertexIndex
+        :
+        : [ptr] "" (ptr),
+    );
+}
+
+/// Output fragment depth from a `Fragment` entrypoint
+/// `ptr` must be a reference to variable or struct field.
+pub fn fragmentCoord(comptime ptr: *addrspace(.input) @Vector(4, f32)) void {
+    asm volatile (
+        \\OpDecorate %ptr BuiltIn FragCoord
+        :
+        : [ptr] "" (ptr),
+    );
+}
+
+/// Output fragment depth from a `Fragment` entrypoint
+/// `ptr` must be a reference to variable or struct field.
+pub fn fragmentDepth(comptime ptr: *addrspace(.output) f32) void {
+    asm volatile (
+        \\OpDecorate %ptr BuiltIn FragDepth
+        :
+        : [ptr] "" (ptr),
+    );
+}
+
+/// Forms the main linkage for `input` and `output` address spaces.
+/// `ptr` must be a reference to variable or struct field.
+pub fn location(comptime ptr: anytype, comptime loc: u32) void {
+    const code = comptimePrint("OpDecorate %ptr Location {}", .{loc});
+    asm volatile (code
+        :
+        : [ptr] "" (ptr),
+    );
+}
+
+/// Forms the main linkage for `input` and `output` address spaces.
+/// `ptr` must be a reference to variable or struct field.
+pub fn binding(comptime ptr: anytype, comptime group: u32, comptime bind: u32) void {
+    const code = comptimePrint(
+        \\OpDecorate %ptr DescriptorSet {}
+        \\OpDecorate %ptr Binding {}
+    , .{ group, bind });
+    asm volatile (code
+        :
+        : [ptr] "" (ptr),
+    );
+}
+
+pub const Origin = enum(u32) {
+    /// Increase toward the right and downward
+    upper_left = 7,
+    /// Increase toward the right and upward
+    lower_left = 8,
+};
+
+/// The coordinates appear to originate in the specified `origin`.
+/// Only valid with the `Fragment` calling convention.
+pub fn fragmentOrigin(comptime entry_point: anytype, comptime origin: Origin) void {
+    const origin_enum = switch (origin) {
+        .upper_left => .OriginUpperLeft,
+        .lower_left => .OriginLowerLeft,
+    };
+    asm volatile ("OpExecutionMode %entry_point " ++ @tagName(origin_enum)
+        :
+        : [entry_point] "" (entry_point),
+    );
+}
+
+pub const DepthMode = enum(u32) {
+    /// Declares that this entry point dynamically writes the
+    /// `fragmentDepth` built in-decorated variable.
+    replacing = 12,
+    /// Indicates that per-fragment tests may assume that
+    /// any `fragmentDepth` built in-decorated value written by the shader is
+    /// greater-than-or-equal to the fragment’s interpolated depth value
+    greater = 14,
+    /// Indicates that per-fragment tests may assume that
+    /// any `fragmentDepth` built in-decorated value written by the shader is
+    /// less-than-or-equal to the fragment’s interpolated depth value
+    less = 15,
+    /// Indicates that per-fragment tests may assume that
+    /// any `fragmentDepth` built in-decorated value written by the shader is
+    /// the same as the fragment’s interpolated depth value
+    unchanged = 16,
+};
+
+/// Only valid with the `Fragment` calling convention.
+pub fn depthMode(comptime entry_point: anytype, comptime mode: DepthMode) void {
+    const code = comptimePrint("OpExecutionMode %entry_point {}", .{@intFromEnum(mode)});
+    asm volatile (code
+        :
+        : [entry_point] "" (entry_point),
+    );
+}
+
+/// Indicates the workgroup size in the `x`, `y`, and `z` dimensions.
+/// Only valid with the `GLCompute` or `Kernel` calling conventions.
+pub fn workgroupSize(comptime entry_point: anytype, comptime size: @Vector(3, u32)) void {
+    const code = comptimePrint("OpExecutionMode %entry_point LocalSize {} {} {}", .{
+        size[0],
+        size[1],
+        size[2],
+    });
+    asm volatile (code
+        :
+        : [entry_point] "" (entry_point),
+    );
+}
+
+/// A hint to the client, which indicates the workgroup size in the `x`, `y`, and `z` dimensions.
+/// Only valid with the `GLCompute` or `Kernel` calling conventions.
+pub fn workgroupSizeHint(comptime entry_point: anytype, comptime size: @Vector(3, u32)) void {
+    const code = comptimePrint("OpExecutionMode %entry_point LocalSizeHint {} {} {}", .{
+        size[0],
+        size[1],
+        size[2],
+    });
+    asm volatile (code
+        :
+        : [entry_point] "" (entry_point),
+    );
+}
+
+/// Same as `kernelWorkgroupSize` but with runtime-known sizes
+pub fn workgroupSizeId(comptime entry_point: anytype, comptime size: @Vector(3, u32)) void {
+    const code = comptimePrint("OpExecutionMode %entry_point LocalSize {} {} {}", .{
+        size[0],
+        size[1],
+        size[2],
+    });
+    asm volatile (code
+        :
+        : [entry_point] "" (entry_point),
+    );
+}
+
+/// Same as `kernelWorkgroupSizeHint` but with runtime-known sizes
+pub fn workgroupSizeHintId(comptime entry_point: anytype, comptime size: @Vector(3, u32)) void {
+    const code = comptimePrint("OpExecutionMode %entry_point LocalSizeHint {} {} {}", .{
+        size[0],
+        size[1],
+        size[2],
+    });
+    asm volatile (code
+        :
+        : [entry_point] "" (entry_point),
+    );
+}
diff --git a/lib/std/std.zig b/lib/std/std.zig
index 66e30c4b4ee1..9f249c2a6227 100644
--- a/lib/std/std.zig
+++ b/lib/std/std.zig
@@ -104,6 +104,9 @@ pub const fmt = @import("fmt.zig");
 /// File system-related functionality.
 pub const fs = @import("fs.zig");
 
+/// GPU programming helpers.
+pub const gpu = @import("gpu.zig");
+
 /// Fast hashing functions (i.e. not cryptographically secure).
 pub const hash = @import("hash.zig");
 pub const hash_map = @import("hash_map.zig");