gl_shader.hh

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/* SPDX-FileCopyrightText: 2020 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

 
#pragma once
 
#include "MEM_guardedalloc.h"
 
#include <epoxy/gl.h>
 
#include "BLI_map.hh"
#include "BLI_subprocess.hh"
#include "BLI_utility_mixins.hh"
 
#include "GPU_capabilities.hh"
#include "gpu_shader_create_info.hh"
#include "gpu_shader_private.hh"
 
#include <functional>
#include <mutex>
 
namespace blender::gpu {

struct GLSource {
  std::string source;
  std::optional<StringRefNull> source_ref;
 
  GLSource() = default;
  GLSource(StringRefNull other_source);
};
class GLSources : public Vector<GLSource> {
 public:
  GLSources &operator=(Span<StringRefNull> other);
  Vector<StringRefNull> sources_get() const;
  std::string to_string() const;
};

struct GLSourcesBaked : NonCopyable {
  std::string comp;
  std::string vert;
  std::string geom;
  std::string frag;
 
  /* Returns the size (in bytes) required to store the source of all the used stages. */
  size_t size();
};

class GLShader : public Shader {
  friend shader::ShaderCreateInfo;
  friend shader::StageInterfaceInfo;
  friend class GLSubprocessShaderCompiler;
  friend class GLShaderCompiler;
 
 private:
  struct GLProgram {
    GLuint program_id = 0;
    GLuint vert_shader = 0;
    GLuint geom_shader = 0;
    GLuint frag_shader = 0;
    GLuint compute_shader = 0;
 
    std::mutex compilation_mutex;
 
    GLProgram() {}
    ~GLProgram();
 
    void program_link(StringRefNull shader_name);
  };
 
  using GLProgramCacheKey = Vector<shader::SpecializationConstant::Value>;
  Map<GLProgramCacheKey, std::unique_ptr<GLProgram>> program_cache_;
 
  std::mutex program_cache_mutex_;

  GLProgram *main_program_ = nullptr;
 
  /* When true, the shader generates its GLSources but it's not compiled.
   * (Used for batch compilation) */
  bool async_compilation_ = false;

  GLSources vertex_sources_;
  GLSources geometry_sources_;
  GLSources fragment_sources_;
  GLSources compute_sources_;
 
  Vector<const char *> specialization_constant_names_;
 
  void update_program_and_sources(GLSources &stage_sources, MutableSpan<StringRefNull> sources);

  GLShader::GLProgram &program_get(const shader::SpecializationConstants *constants_state);

  bool compilation_failed_ = false;
 
  std::string debug_source;
 
 public:
  GLShader(const char *name);
  ~GLShader();
 
  void init(const shader::ShaderCreateInfo &info, bool is_batch_compilation) override;

  void vertex_shader_from_glsl(MutableSpan<StringRefNull> sources) override;
  void geometry_shader_from_glsl(MutableSpan<StringRefNull> sources) override;
  void fragment_shader_from_glsl(MutableSpan<StringRefNull> sources) override;
  void compute_shader_from_glsl(MutableSpan<StringRefNull> sources) override;
  bool finalize(const shader::ShaderCreateInfo *info = nullptr) override;
  bool post_finalize(const shader::ShaderCreateInfo *info = nullptr);
  void warm_cache(int /*limit*/) override {};
 
  std::string resources_declare(const shader::ShaderCreateInfo &info) const override;
  std::string constants_declare(const shader::SpecializationConstants &constants_state) const;
  std::string vertex_interface_declare(const shader::ShaderCreateInfo &info) const override;
  std::string fragment_interface_declare(const shader::ShaderCreateInfo &info) const override;
  std::string geometry_interface_declare(const shader::ShaderCreateInfo &info) const override;
  std::string geometry_layout_declare(const shader::ShaderCreateInfo &info) const override;
  std::string compute_layout_declare(const shader::ShaderCreateInfo &info) const override;
 
  void bind(const shader::SpecializationConstants *constants_state) override;
  void unbind() override;
 
  void uniform_float(int location, int comp_len, int array_size, const float *data) override;
  void uniform_int(int location, int comp_len, int array_size, const int *data) override;
 
  bool is_compute() const
  {
    if (!vertex_sources_.is_empty()) {
      return false;
    }
    if (!compute_sources_.is_empty()) {
      return true;
    }
    return main_program_->compute_shader != 0;
  }
 
  GLSourcesBaked get_sources();
 
 private:
  StringRefNull glsl_patch_get(GLenum gl_stage);
 
  bool has_specialization_constants() const
  {
    return constants->types.is_empty() == false;
  }

  GLuint create_shader_stage(GLenum gl_stage,
                             MutableSpan<StringRefNull> sources,
                             GLSources &gl_sources,
                             const shader::SpecializationConstants &constants_state);

  std::string workaround_geometry_shader_source_create(const shader::ShaderCreateInfo &info);
 
  bool do_geometry_shader_injection(const shader::ShaderCreateInfo *info) const;
 
  MEM_CXX_CLASS_ALLOC_FUNCS("GLShader");
};
 
class GLShaderCompiler : public ShaderCompiler {
 public:
  GLShaderCompiler()
      : ShaderCompiler(GPU_max_parallel_compilations(), GPUWorker::ContextType::PerThread, true) {
        };
 
  virtual void specialize_shader(ShaderSpecialization &specialization) override;
};
 
#if BLI_SUBPROCESS_SUPPORT
 
class GLCompilerWorker {
  friend class GLSubprocessShaderCompiler;
 
 private:
  BlenderSubprocess subprocess_;
  std::unique_ptr<SharedMemory> shared_mem_;
  std::unique_ptr<SharedSemaphore> start_semaphore_;
  std::unique_ptr<SharedSemaphore> end_semaphore_;
  std::unique_ptr<SharedSemaphore> close_semaphore_;
  enum State {
    /* The worker has been acquired and the compilation has been requested. */
    COMPILATION_REQUESTED,
    /* The shader binary result is ready to be read. */
    COMPILATION_READY,
    /* The binary result has been loaded into a program and the worker can be released. */
    COMPILATION_FINISHED,
    /* The worker is not currently in use and can be acquired. */
    AVAILABLE
  };
  std::atomic<State> state_ = AVAILABLE;
  double compilation_start = 0;
 
  GLCompilerWorker();
  ~GLCompilerWorker();
 
  void compile(const GLSourcesBaked &sources);
  bool block_until_ready();
  bool load_program_binary(GLint program);
  void release();
 
  /* Check if the process may have closed/crashed/hanged. */
  bool is_lost();
};
 
class GLSubprocessShaderCompiler : public ShaderCompiler {
 private:
  Vector<GLCompilerWorker *> workers_;
  std::mutex workers_mutex_;
 
  GLCompilerWorker *get_compiler_worker();
 
  GLShader::GLProgram *specialization_program_get(ShaderSpecialization &specialization);
 
 public:
  GLSubprocessShaderCompiler()
      : ShaderCompiler(GPU_max_parallel_compilations(), GPUWorker::ContextType::PerThread, true) {
        };
  virtual ~GLSubprocessShaderCompiler() override;
 
  virtual Shader *compile_shader(const shader::ShaderCreateInfo &info) override;
  virtual void specialize_shader(ShaderSpecialization &specialization) override;
};
 
#else
 
class GLSubprocessShaderCompiler : public ShaderCompiler {};
 
#endif
 
class GLLogParser : public GPULogParser {
 public:
  const char *parse_line(const char *source_combined,
                         const char *log_line,
                         GPULogItem &log_item) override;
 
 protected:
  const char *skip_severity_prefix(const char *log_line, GPULogItem &log_item);
  const char *skip_severity_keyword(const char *log_line, GPULogItem &log_item);
 
  MEM_CXX_CLASS_ALLOC_FUNCS("GLLogParser");
};
 
}  // namespace blender::gpu