GPU: Add command line option to output shader source

This command line outputs only shaders whose name
matches the argument string.

Metal is missing as it waits until #147010 lands.

Pull Request: https://projects.blender.org/blender/blender/pulls/147970

source/blender/blenkernel/BKE_global.hh

@@ -170,7 +170,13 @@ struct Global {
    * Triggers a GPU capture if the name matches a DebugScope.
    * Set using `--debug-gpu-scope-capture "debug_scope"`.
    */
-  char gpu_debug_scope_name[200];
+  char gpu_debug_scope_name[100];
+
+  /**
+   * Save final shader string to disk.
+   * Set using `--debug-gpu-shader-source "shader_name"`.
+   */
+  char gpu_debug_shader_source_name[100];
 
   bool profile_gpu;
 };

source/blender/gpu/opengl/gl_shader.cc

@@ -38,6 +38,7 @@
 
 #include <fmt/format.h>
 
+#include <filesystem>
 #include <fstream>
 #include <iostream>
 #include <sstream>
@@ -1218,6 +1219,21 @@ StringRefNull GLShader::glsl_patch_get(GLenum gl_stage)
   return "";
 }
 
+static StringRefNull stage_name_get(GLenum gl_stage)
+{
+  switch (gl_stage) {
+    case GL_VERTEX_SHADER:
+      return "vertex";
+    case GL_GEOMETRY_SHADER:
+      return "geometry";
+    case GL_FRAGMENT_SHADER:
+      return "fragment";
+    case GL_COMPUTE_SHADER:
+      return "compute";
+  }
+  return "";
+}
+
 GLuint GLShader::create_shader_stage(GLenum gl_stage,
                                      MutableSpan<StringRefNull> sources,
                                      GLSources &gl_sources,
@@ -1246,21 +1262,7 @@ GLuint GLShader::create_shader_stage(GLenum gl_stage,
 
   if (DEBUG_LOG_SHADER_SRC_ON_ERROR) {
     /* Store the generated source for printing in case the link fails. */
-    StringRefNull source_type;
-    switch (gl_stage) {
-      case GL_VERTEX_SHADER:
-        source_type = "VertShader";
-        break;
-      case GL_GEOMETRY_SHADER:
-        source_type = "GeomShader";
-        break;
-      case GL_FRAGMENT_SHADER:
-        source_type = "FragShader";
-        break;
-      case GL_COMPUTE_SHADER:
-        source_type = "ComputeShader";
-        break;
-    }
+    StringRefNull source_type = stage_name_get(gl_stage);
 
     debug_source += "\n\n----------" + source_type + "----------\n\n";
     for (StringRefNull source : sources) {
@@ -1281,6 +1283,24 @@ GLuint GLShader::create_shader_stage(GLenum gl_stage,
 
   std::string concat_source = fmt::to_string(fmt::join(sources, ""));
 
+  std::string full_name = this->name_get() + "_" + stage_name_get(gl_stage);
+
+  if (this->name_get() == G.gpu_debug_shader_source_name) {
+    namespace fs = std::filesystem;
+    fs::path shader_dir = fs::current_path() / "Shaders";
+    fs::create_directories(shader_dir);
+    fs::path file_path = shader_dir / (full_name + ".glsl");
+
+    std::ofstream output_source_file(file_path);
+    if (output_source_file) {
+      output_source_file << concat_source;
+      output_source_file.close();
+    }
+    else {
+      std::cerr << "Shader Source Debug: Failed to open file: " << file_path << "\n";
+    }
+  }
+
   /* Patch line directives so that we can make error reporting consistent. */
   size_t start_pos = 0;
   while ((start_pos = concat_source.find("#line ", start_pos)) != std::string::npos) {

source/blender/gpu/vulkan/vk_shader_compiler.cc

@@ -19,6 +19,11 @@
 #include "vk_shader.hh"
 #include "vk_shader_compiler.hh"
 
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <string>
+
 namespace blender::gpu {
 
 static std::optional<std::string> cache_dir_get()
@@ -212,10 +217,27 @@ static bool compile_ex(shaderc::Compiler &compiler,
     options.SetGenerateDebugInfo();
   }
 
+  std::string full_name = shader.name_get() + "_" + to_stage_name(stage);
+
+  if (shader.name_get() == G.gpu_debug_shader_source_name) {
+    namespace fs = std::filesystem;
+    fs::path shader_dir = fs::current_path() / "Shaders";
+    fs::create_directories(shader_dir);
+    fs::path file_path = shader_dir / (full_name + ".glsl");
+
+    std::ofstream output_source_file(file_path);
+    if (output_source_file) {
+      output_source_file << shader_module.combined_sources;
+      output_source_file.close();
+    }
+    else {
+      std::cerr << "Shader Source Debug: Failed to open file: " << file_path << "\n";
+    }
+  }
+
   /* Removes line directive. */
   std::string sources = patch_line_directives(shader_module.combined_sources);
 
-  std::string full_name = shader.name_get() + "_" + to_stage_name(stage);
   shader_module.compilation_result = compiler.CompileGlslToSpv(
       sources, stage, full_name.c_str(), options);
   bool compilation_succeeded = shader_module.compilation_result.GetCompilationStatus() ==

source/creator/creator_args.cc

@@ -763,6 +763,7 @@ static void print_help(bArgs *ba, bool all)
   BLI_args_print_arg_doc(ba, "--debug-gpu-force-workarounds");
   BLI_args_print_arg_doc(ba, "--debug-gpu-compile-shaders");
   BLI_args_print_arg_doc(ba, "--debug-gpu-shader-debug-info");
+  BLI_args_print_arg_doc(ba, "--debug-gpu-shader-source");
   if (defs.with_renderdoc) {
     BLI_args_print_arg_doc(ba, "--debug-gpu-scope-capture");
     BLI_args_print_arg_doc(ba, "--debug-gpu-renderdoc");
@@ -1545,6 +1546,20 @@ static int arg_handle_debug_gpu_scope_capture_set(int argc, const char **argv, v
   return 0;
 }
 
+static const char arg_handle_debug_gpu_shader_source_doc[] =
+    "\n"
+    "\tCapture the GPU commands issued inside the give scope name."
+    "\tFiles are saved in the current working directory inside a folder named \"Shaders\".";
+static int arg_handle_debug_gpu_shader_source(int argc, const char **argv, void * /*data*/)
+{
+  if (argc > 1) {
+    STRNCPY(G.gpu_debug_scope_name, argv[1]);
+    return 1;
+  }
+  fprintf(stderr, "\nError: you must specify a shader name to capture.\n");
+  return 0;
+}
+
 static const char arg_handle_debug_gpu_renderdoc_set_doc[] =
     "\n"
     "\tEnable RenderDoc integration for GPU frame grabbing and debugging.";
@@ -3014,6 +3029,8 @@ void main_args_setup(bContext *C, bArgs *ba, bool all)
                "--debug-gpu-compile-shaders",
                CB(arg_handle_debug_gpu_compile_shaders_set),
                nullptr);
+  BLI_args_add(
+      ba, nullptr, "--debug-gpu-shader-source", CB(arg_handle_debug_gpu_shader_source), nullptr);
   if (defs.with_renderdoc) {
     BLI_args_add(ba,
                  nullptr,