Merge pull request #2736 from ghostty-org/push-sltwuokrztpt

macos: enable Metal shader logging

.github/workflows/test.yml

@@ -196,6 +196,9 @@ jobs:
           name: ghostty
           authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
 
+      - name: XCode Select
+        run: sudo xcode-select -s /Applications/Xcode_16.0.app
+
       - name: Test All
         run: |
           # OpenGL
@@ -352,6 +355,9 @@ jobs:
           name: ghostty
           authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
 
+      - name: XCode Select
+        run: sudo xcode-select -s /Applications/Xcode_16.0.app
+
       - name: test
         run: nix develop -c zig build test
 

build.zig

@@ -1385,10 +1385,21 @@ fn addMetallib(
     b: *std.Build,
     step: *std.Build.Step.Compile,
 ) !void {
+    const optimize = step.root_module.optimize.?;
+
     const metal_step = MetallibStep.create(b, .{
         .name = "Ghostty",
         .target = step.root_module.resolved_target.?,
         .sources = &.{b.path("src/renderer/shaders/cell.metal")},
+        .logging = switch (optimize) {
+            .Debug,
+            => true,
+
+            .ReleaseFast,
+            .ReleaseSmall,
+            .ReleaseSafe,
+            => false,
+        },
     });
 
     metal_step.output.addStepDependencies(&step.step);

macos/Ghostty.xcodeproj/xcshareddata/xcschemes/Ghostty.xcscheme

@@ -55,6 +55,23 @@
             isEnabled = "YES">
          </CommandLineArgument>
       </CommandLineArguments>
+      <EnvironmentVariables>
+         <EnvironmentVariable
+            key = "MTL_LOG_BUFFER_SIZE"
+            value = "4096"
+            isEnabled = "YES">
+         </EnvironmentVariable>
+         <EnvironmentVariable
+            key = "MTL_LOG_LEVEL"
+            value = "MTLLogLevelDebug"
+            isEnabled = "YES">
+         </EnvironmentVariable>
+         <EnvironmentVariable
+            key = "MTL_LOG_TO_STDERR"
+            value = "1"
+            isEnabled = "YES">
+         </EnvironmentVariable>
+      </EnvironmentVariables>
       <AdditionalOptions>
          <AdditionalOption
             key = "NSZombieEnabled"

src/build/MetallibStep.zig

@@ -16,6 +16,9 @@ pub const Options = struct {
 
     /// The Metal source files.
     sources: []const LazyPath,
+
+    /// Whether to enable Metal shader logging.
+    logging: bool = false,
 };
 
 step: *Step,
@@ -42,7 +45,20 @@ pub fn create(b: *std.Build, opts: Options) *MetallibStep {
         b,
         b.fmt("metal {s}", .{opts.name}),
     );
-    run_ir.addArgs(&.{ "xcrun", "-sdk", sdk, "metal", "-o" });
+    run_ir.addArgs(&.{
+        "xcrun",
+        "-sdk",
+        sdk,
+        "metal",
+        "-std=metal3.2",
+    });
+
+    if (opts.logging) run_ir.addArgs(&.{
+        // https://developer.apple.com/documentation/metal/logging_shader_debug_messages
+        "-fmetal-enable-logging",
+    });
+
+    run_ir.addArgs(&.{"-o"});
     const output_ir = run_ir.addOutputFileArg(b.fmt("{s}.ir", .{opts.name}));
     run_ir.addArgs(&.{"-c"});
     for (opts.sources) |source| run_ir.addFileArg(source);

src/renderer/shaders/cell.metal

@@ -2,6 +2,8 @@
 
 using namespace metal;
 
+constant os_log logger("com.mitchellh.ghostty", "cell");
+
 enum Padding : uint8_t {
   EXTEND_LEFT = 1u,
   EXTEND_RIGHT = 2u,
@@ -79,9 +81,7 @@ struct FullScreenVertexOut {
   float4 position [[position]];
 };
 
-vertex FullScreenVertexOut full_screen_vertex(
-  uint vid [[vertex_id]]
-) {
+vertex FullScreenVertexOut full_screen_vertex(uint vid [[vertex_id]]) {
   FullScreenVertexOut out;
 
   float4 position;
@@ -112,12 +112,11 @@ vertex FullScreenVertexOut full_screen_vertex(
 //-------------------------------------------------------------------
 #pragma mark - Cell BG Shader
 
-fragment float4 cell_bg_fragment(
-  FullScreenVertexOut in [[stage_in]],
-  constant uchar4 *cells [[buffer(0)]],
-  constant Uniforms& uniforms [[buffer(1)]]
-) {
-  int2 grid_pos = int2(floor((in.position.xy - uniforms.grid_padding.wx) / uniforms.cell_size));
+fragment float4 cell_bg_fragment(FullScreenVertexOut in [[stage_in]],
+                                 constant uchar4* cells [[buffer(0)]],
+                                 constant Uniforms& uniforms [[buffer(1)]]) {
+  int2 grid_pos = int2(
+      floor((in.position.xy - uniforms.grid_padding.wx) / uniforms.cell_size));
 
   // Clamp x position, extends edge bg colors in to padding on sides.
   if (grid_pos.x < 0) {
@@ -197,12 +196,12 @@ struct CellTextVertexOut {
   float2 tex_coord;
 };
 
-vertex CellTextVertexOut cell_text_vertex(
-  uint vid [[vertex_id]],
+vertex CellTextVertexOut cell_text_vertex(uint vid [[vertex_id]],
                                           CellTextVertexIn in [[stage_in]],
-  constant Uniforms& uniforms [[buffer(1)]],
-  constant uchar4 *bg_colors [[buffer(2)]]
-) {
+                                          constant Uniforms& uniforms
+                                          [[buffer(1)]],
+                                          constant uchar4* bg_colors
+                                          [[buffer(2)]]) {
   // Convert the grid x, y into world space x, y by accounting for cell size
   float2 cell_pos = uniforms.cell_size * float2(in.grid_pos);
 
@@ -287,36 +286,31 @@ vertex CellTextVertexOut cell_text_vertex(
   // and Powerline glyphs to be unaffected (else parts of the line would
   // have different colors as some parts are displayed via background colors).
   if (uniforms.min_contrast > 1.0f && in.mode == MODE_TEXT) {
-    float4 bg_color = float4(bg_colors[in.grid_pos.y * uniforms.grid_size.x + in.grid_pos.x]) / 255.0f;
+    float4 bg_color =
+        float4(
+            bg_colors[in.grid_pos.y * uniforms.grid_size.x + in.grid_pos.x]) /
+        255.0f;
     out.color = contrasted_color(uniforms.min_contrast, out.color, bg_color);
   }
 
   // If this cell is the cursor cell, then we need to change the color.
-  if (
-    in.mode != MODE_TEXT_CURSOR &&
-    (
-      in.grid_pos.x == uniforms.cursor_pos.x ||
-      uniforms.cursor_wide &&
-        in.grid_pos.x == uniforms.cursor_pos.x + 1
-    ) &&
-    in.grid_pos.y == uniforms.cursor_pos.y
-  ) {
+  if (in.mode != MODE_TEXT_CURSOR &&
+      (in.grid_pos.x == uniforms.cursor_pos.x ||
+       uniforms.cursor_wide && in.grid_pos.x == uniforms.cursor_pos.x + 1) &&
+      in.grid_pos.y == uniforms.cursor_pos.y) {
     out.color = float4(uniforms.cursor_color) / 255.0f;
   }
 
   return out;
 }
 
-fragment float4 cell_text_fragment(
-  CellTextVertexOut in [[stage_in]],
-  texture2d<float> textureGrayscale [[texture(0)]],
-  texture2d<float> textureColor [[texture(1)]]
-) {
-  constexpr sampler textureSampler(
-    coord::pixel,
-    address::clamp_to_edge,
-    filter::nearest
-  );
+fragment float4 cell_text_fragment(CellTextVertexOut in [[stage_in]],
+                                   texture2d<float> textureGrayscale
+                                   [[texture(0)]],
+                                   texture2d<float> textureColor
+                                   [[texture(1)]]) {
+  constexpr sampler textureSampler(coord::pixel, address::clamp_to_edge,
+                                   filter::nearest);
 
   switch (in.mode) {
     default:
@@ -367,12 +361,10 @@ struct ImageVertexOut {
   float2 tex_coord;
 };
 
-vertex ImageVertexOut image_vertex(
-  uint vid [[vertex_id]],
+vertex ImageVertexOut image_vertex(uint vid [[vertex_id]],
                                    ImageVertexIn in [[stage_in]],
                                    texture2d<uint> image [[texture(0)]],
-  constant Uniforms& uniforms [[buffer(1)]]
-) {
+                                   constant Uniforms& uniforms [[buffer(1)]]) {
   // The size of the image in pixels
   float2 image_size = float2(image.get_width(), image.get_height());
 
@@ -409,10 +401,8 @@ vertex ImageVertexOut image_vertex(
   return out;
 }
 
-fragment float4 image_fragment(
-  ImageVertexOut in [[stage_in]],
-  texture2d<uint> image [[texture(0)]]
-) {
+fragment float4 image_fragment(ImageVertexOut in [[stage_in]],
+                               texture2d<uint> image [[texture(0)]]) {
   constexpr sampler textureSampler(address::clamp_to_edge, filter::linear);
 
   // Ehhhhh our texture is in RGBA8Uint but our color attachment is
@@ -426,4 +416,3 @@ fragment float4 image_fragment(
   result.rgb *= result.a;
   return result;
 }
-