/* SPDX-FileCopyrightText: 2021 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup gpu
 *
 * Descriptor type used to define shader structure, resources and interfaces.
 *
 * Some rule of thumb:
 * - Do not include anything else than this file in each info file.
 */

#pragma once

#include "BLI_hash.hh"
#include "BLI_string_ref.hh"
#include "BLI_vector.hh"
#include "GPU_common_types.hh"
#include "GPU_material.hh"
#include "GPU_texture.hh"

#include <iostream>

namespace blender::gpu::shader {

/* Helps intellisense / auto-completion. */
#ifndef GPU_SHADER_CREATE_INFO
#  define GPU_SHADER_INTERFACE_INFO(_interface, _inst_name) \
    StageInterfaceInfo _interface(#_interface, _inst_name); \
    _interface
#  define GPU_SHADER_CREATE_INFO(_info) \
    ShaderCreateInfo _info(#_info); \
    _info
#endif

/* All of these functions is a bit out of place */
static inline Type to_type(const eGPUType type)
{
  switch (type) {
    case GPU_FLOAT:
      return Type::FLOAT;
    case GPU_VEC2:
      return Type::VEC2;
    case GPU_VEC3:
      return Type::VEC3;
    case GPU_VEC4:
      return Type::VEC4;
    case GPU_MAT3:
      return Type::MAT3;
    case GPU_MAT4:
      return Type::MAT4;
    default:
      BLI_assert_msg(0, "Error: Cannot convert eGPUType to shader::Type.");
      return Type::FLOAT;
  }
}

static inline std::ostream &operator<<(std::ostream &stream, const Type type)
{
  switch (type) {
    case Type::FLOAT:
      return stream << "float";
    case Type::VEC2:
      return stream << "vec2";
    case Type::VEC3:
      return stream << "vec3";
    case Type::VEC4:
      return stream << "vec4";
    case Type::MAT3:
      return stream << "mat3";
    case Type::MAT4:
      return stream << "mat4";
    case Type::VEC3_101010I2:
      return stream << "vec3_1010102_Inorm";
    case Type::UCHAR:
      return stream << "uchar";
    case Type::UCHAR2:
      return stream << "uchar2";
    case Type::UCHAR3:
      return stream << "uchar3";
    case Type::UCHAR4:
      return stream << "uchar4";
    case Type::CHAR:
      return stream << "char";
    case Type::CHAR2:
      return stream << "char2";
    case Type::CHAR3:
      return stream << "char3";
    case Type::CHAR4:
      return stream << "char4";
    case Type::INT:
      return stream << "int";
    case Type::IVEC2:
      return stream << "ivec2";
    case Type::IVEC3:
      return stream << "ivec3";
    case Type::IVEC4:
      return stream << "ivec4";
    case Type::UINT:
      return stream << "uint";
    case Type::UVEC2:
      return stream << "uvec2";
    case Type::UVEC3:
      return stream << "uvec3";
    case Type::UVEC4:
      return stream << "uvec4";
    case Type::USHORT:
      return stream << "ushort";
    case Type::USHORT2:
      return stream << "ushort2";
    case Type::USHORT3:
      return stream << "ushort3";
    case Type::USHORT4:
      return stream << "ushort4";
    case Type::SHORT:
      return stream << "short";
    case Type::SHORT2:
      return stream << "short2";
    case Type::SHORT3:
      return stream << "short3";
    case Type::SHORT4:
      return stream << "short4";
    case Type::BOOL:
      return stream << "bool";
    default:
      BLI_assert(0);
      return stream;
  }
}

static inline std::ostream &operator<<(std::ostream &stream, const eGPUType type)
{
  switch (type) {
    case GPU_CLOSURE:
      return stream << "Closure";
    default:
      return stream << to_type(type);
  }
}

enum class BuiltinBits {
  NONE = 0,
  /**
   * Allow getting barycentric coordinates inside the fragment shader.
   * \note Emulated on OpenGL.
   */
  BARYCENTRIC_COORD = (1 << 0),
  FRAG_COORD = (1 << 2),
  FRONT_FACING = (1 << 4),
  GLOBAL_INVOCATION_ID = (1 << 5),
  INSTANCE_ID = (1 << 6),
  /**
   * Allow setting the target layer when the output is a layered frame-buffer.
   * \note Emulated through geometry shader on older hardware.
   */
  LAYER = (1 << 7),
  LOCAL_INVOCATION_ID = (1 << 8),
  LOCAL_INVOCATION_INDEX = (1 << 9),
  NUM_WORK_GROUP = (1 << 10),
  POINT_COORD = (1 << 11),
  POINT_SIZE = (1 << 12),
  PRIMITIVE_ID = (1 << 13),
  VERTEX_ID = (1 << 14),
  WORK_GROUP_ID = (1 << 15),
  WORK_GROUP_SIZE = (1 << 16),
  /**
   * Allow setting the target viewport when using multi viewport feature.
   * \note Emulated through geometry shader on older hardware.
   */
  VIEWPORT_INDEX = (1 << 17),

  /* Texture atomics requires usage options to alter compilation flag. */
  TEXTURE_ATOMIC = (1 << 18),

  /* Not a builtin but a flag we use to tag shaders that use the debug features. */
  USE_DEBUG_DRAW = (1 << 29),
  USE_DEBUG_PRINT = (1 << 30),
};
ENUM_OPERATORS(BuiltinBits, BuiltinBits::USE_DEBUG_PRINT);

/**
 * Follow convention described in:
 * https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_conservative_depth.txt
 */
enum class DepthWrite {
  /* UNCHANGED specified as default to indicate gl_FragDepth is not used. */
  UNCHANGED = 0,
  ANY,
  GREATER,
  LESS,
};

/* Samplers & images. */
enum class ImageType {
  /** Color samplers/image. */
  FLOAT_BUFFER = 0,
  FLOAT_1D,
  FLOAT_1D_ARRAY,
  FLOAT_2D,
  FLOAT_2D_ARRAY,
  FLOAT_3D,
  FLOAT_CUBE,
  FLOAT_CUBE_ARRAY,
  INT_BUFFER,
  INT_1D,
  INT_1D_ARRAY,
  INT_2D,
  INT_2D_ARRAY,
  INT_3D,
  INT_CUBE,
  INT_CUBE_ARRAY,
  UINT_BUFFER,
  UINT_1D,
  UINT_1D_ARRAY,
  UINT_2D,
  UINT_2D_ARRAY,
  UINT_3D,
  UINT_CUBE,
  UINT_CUBE_ARRAY,
  /** Depth samplers (not supported as image). */
  SHADOW_2D,
  SHADOW_2D_ARRAY,
  SHADOW_CUBE,
  SHADOW_CUBE_ARRAY,
  DEPTH_2D,
  DEPTH_2D_ARRAY,
  DEPTH_CUBE,
  DEPTH_CUBE_ARRAY,
  /** Atomic texture type wrappers.
   * For OpenGL, these map to the equivalent (U)INT_* types.
   * NOTE: Atomic variants MUST be used if the texture bound to this resource has usage flag:
   * `GPU_TEXTURE_USAGE_ATOMIC`, even if atomic texture operations are not used in the given
   * shader.
   * The shader source MUST also utilize the correct atomic sampler handle e.g.
   * `usampler2DAtomic` in conjunction with these types, for passing texture/image resources into
   * functions. */
  UINT_2D_ATOMIC,
  UINT_2D_ARRAY_ATOMIC,
  UINT_3D_ATOMIC,
  INT_2D_ATOMIC,
  INT_2D_ARRAY_ATOMIC,
  INT_3D_ATOMIC
};

/* Storage qualifiers. */
enum class Qualifier {
  /** Restrict flag is set by default. Unless specified otherwise. */
  NO_RESTRICT = (1 << 0),
  READ = (1 << 1),
  WRITE = (1 << 2),
  /** Shorthand version of combined flags. */
  READ_WRITE = READ | WRITE,
  QUALIFIER_MAX = (WRITE << 1) - 1,
};
ENUM_OPERATORS(Qualifier, Qualifier::QUALIFIER_MAX);

enum class Frequency {
  BATCH = 0,
  PASS,
};

/* Dual Source Blending Index. */
enum class DualBlend {
  NONE = 0,
  SRC_0,
  SRC_1,
};

/* Interpolation qualifiers. */
enum class Interpolation {
  SMOOTH = 0,
  FLAT,
  NO_PERSPECTIVE,
};

/** Input layout for geometry shader. */
enum class PrimitiveIn {
  POINTS = 0,
  LINES,
  LINES_ADJACENCY,
  TRIANGLES,
  TRIANGLES_ADJACENCY,
};

/** Output layout for geometry shader. */
enum class PrimitiveOut {
  POINTS = 0,
  LINE_STRIP,
  TRIANGLE_STRIP,
  LINES,
  TRIANGLES,
};

struct StageInterfaceInfo {
  struct InOut {
    Interpolation interp;
    Type type;
    StringRefNull name;
  };

  StringRefNull name;
  /**
   * Name of the instance of the block (used to access).
   * Can be empty string (i.e: "") only if not using geometry shader.
   */
  StringRefNull instance_name;
  /** List of all members of the interface. */
  Vector<InOut> inouts;

  StageInterfaceInfo(const char *name_, const char *instance_name_)
      : name(name_), instance_name(instance_name_){};
  ~StageInterfaceInfo(){};

  using Self = StageInterfaceInfo;

  Self &smooth(Type type, StringRefNull _name)
  {
    inouts.append({Interpolation::SMOOTH, type, _name});
    return *(Self *)this;
  }

  Self &flat(Type type, StringRefNull _name)
  {
    inouts.append({Interpolation::FLAT, type, _name});
    return *(Self *)this;
  }

  Self &no_perspective(Type type, StringRefNull _name)
  {
    inouts.append({Interpolation::NO_PERSPECTIVE, type, _name});
    return *(Self *)this;
  }
};

/**
 * \brief Describe inputs & outputs, stage interfaces, resources and sources of a shader.
 *        If all data is correctly provided, this is all that is needed to create and compile
 *        a #GPUShader.
 *
 * IMPORTANT: All strings are references only. Make sure all the strings used by a
 *            #ShaderCreateInfo are not freed until it is consumed or deleted.
 */
struct ShaderCreateInfo {
  /** Shader name for debugging. */
  StringRefNull name_;
  /** True if the shader is static and can be pre-compiled at compile time. */
  bool do_static_compilation_ = false;
  /** If true, all additionally linked create info will be merged into this one. */
  bool finalized_ = false;
  /** If true, all resources will have an automatic location assigned. */
  bool auto_resource_location_ = false;
  /** If true, force depth and stencil tests to always happen before fragment shader invocation. */
  bool early_fragment_test_ = false;
  /** If true, force the use of the GL shader introspection for resource location. */
  bool legacy_resource_location_ = false;
  /** Allow optimization when fragment shader writes to `gl_FragDepth`. */
  DepthWrite depth_write_ = DepthWrite::UNCHANGED;
  /** GPU Backend compatibility flag. Temporary requirement until Metal enablement is fully
   * complete. */
  bool metal_backend_only_ = false;
  /**
   * Maximum length of all the resource names including each null terminator.
   * Only for names used by #gpu::ShaderInterface.
   */
  size_t interface_names_size_ = 0;
  /** Manually set builtins. */
  BuiltinBits builtins_ = BuiltinBits::NONE;
  /** Manually set generated code. */
  std::string vertex_source_generated = "";
  std::string fragment_source_generated = "";
  std::string compute_source_generated = "";
  std::string geometry_source_generated = "";
  std::string typedef_source_generated = "";
  /** Manually set generated dependencies. */
  Vector<const char *, 0> dependencies_generated;

#define TEST_EQUAL(a, b, _member) \
  if (!((a)._member == (b)._member)) { \
    return false; \
  }

#define TEST_VECTOR_EQUAL(a, b, _vector) \
  TEST_EQUAL(a, b, _vector.size()); \
  for (auto i : _vector.index_range()) { \
    TEST_EQUAL(a, b, _vector[i]); \
  }

  struct VertIn {
    int index;
    Type type;
    StringRefNull name;

    bool operator==(const VertIn &b) const
    {
      TEST_EQUAL(*this, b, index);
      TEST_EQUAL(*this, b, type);
      TEST_EQUAL(*this, b, name);
      return true;
    }
  };
  Vector<VertIn> vertex_inputs_;

  struct GeometryStageLayout {
    PrimitiveIn primitive_in;
    int invocations;
    PrimitiveOut primitive_out;
    /** Set to -1 by default to check if used. */
    int max_vertices = -1;

    bool operator==(const GeometryStageLayout &b)
    {
      TEST_EQUAL(*this, b, primitive_in);
      TEST_EQUAL(*this, b, invocations);
      TEST_EQUAL(*this, b, primitive_out);
      TEST_EQUAL(*this, b, max_vertices);
      return true;
    }
  };
  GeometryStageLayout geometry_layout_;

  struct ComputeStageLayout {
    int local_size_x = -1;
    int local_size_y = -1;
    int local_size_z = -1;

    bool operator==(const ComputeStageLayout &b)
    {
      TEST_EQUAL(*this, b, local_size_x);
      TEST_EQUAL(*this, b, local_size_y);
      TEST_EQUAL(*this, b, local_size_z);
      return true;
    }
  };
  ComputeStageLayout compute_layout_;

  struct FragOut {
    int index;
    Type type;
    DualBlend blend;
    StringRefNull name;
    /* NOTE: Currently only supported by Metal. */
    int raster_order_group;

    bool operator==(const FragOut &b) const
    {
      TEST_EQUAL(*this, b, index);
      TEST_EQUAL(*this, b, type);
      TEST_EQUAL(*this, b, blend);
      TEST_EQUAL(*this, b, name);
      TEST_EQUAL(*this, b, raster_order_group);
      return true;
    }
  };
  Vector<FragOut> fragment_outputs_;

  using SubpassIn = FragOut;
  Vector<SubpassIn> subpass_inputs_;

  Vector<SpecializationConstant> specialization_constants_;

  struct Sampler {
    ImageType type;
    GPUSamplerState sampler;
    StringRefNull name;
  };

  struct Image {
    eGPUTextureFormat format;
    ImageType type;
    Qualifier qualifiers;
    StringRefNull name;
  };

  struct UniformBuf {
    StringRefNull type_name;
    StringRefNull name;
  };

  struct StorageBuf {
    Qualifier qualifiers;
    StringRefNull type_name;
    StringRefNull name;
  };

  struct Resource {
    enum BindType {
      UNIFORM_BUFFER = 0,
      STORAGE_BUFFER,
      SAMPLER,
      IMAGE,
    };

    BindType bind_type;
    int slot;
    union {
      Sampler sampler;
      Image image;
      UniformBuf uniformbuf;
      StorageBuf storagebuf;
    };

    Resource(BindType type, int _slot) : bind_type(type), slot(_slot){};

    bool operator==(const Resource &b) const
    {
      TEST_EQUAL(*this, b, bind_type);
      TEST_EQUAL(*this, b, slot);
      switch (bind_type) {
        case UNIFORM_BUFFER:
          TEST_EQUAL(*this, b, uniformbuf.type_name);
          TEST_EQUAL(*this, b, uniformbuf.name);
          break;
        case STORAGE_BUFFER:
          TEST_EQUAL(*this, b, storagebuf.qualifiers);
          TEST_EQUAL(*this, b, storagebuf.type_name);
          TEST_EQUAL(*this, b, storagebuf.name);
          break;
        case SAMPLER:
          TEST_EQUAL(*this, b, sampler.type);
          TEST_EQUAL(*this, b, sampler.sampler);
          TEST_EQUAL(*this, b, sampler.name);
          break;
        case IMAGE:
          TEST_EQUAL(*this, b, image.format);
          TEST_EQUAL(*this, b, image.type);
          TEST_EQUAL(*this, b, image.qualifiers);
          TEST_EQUAL(*this, b, image.name);
          break;
      }
      return true;
    }
  };
  /**
   * Resources are grouped by frequency of change.
   * Pass resources are meant to be valid for the whole pass.
   * Batch resources can be changed in a more granular manner (per object/material).
   * Mis-usage will only produce suboptimal performance.
   */
  Vector<Resource> pass_resources_, batch_resources_;

  Vector<StageInterfaceInfo *> vertex_out_interfaces_;
  Vector<StageInterfaceInfo *> geometry_out_interfaces_;

  struct PushConst {
    Type type;
    StringRefNull name;
    int array_size;

    bool operator==(const PushConst &b) const
    {
      TEST_EQUAL(*this, b, type);
      TEST_EQUAL(*this, b, name);
      TEST_EQUAL(*this, b, array_size);
      return true;
    }
  };

  Vector<PushConst> push_constants_;

  /* Sources for resources type definitions. */
  Vector<StringRefNull> typedef_sources_;

  StringRefNull vertex_source_, geometry_source_, fragment_source_, compute_source_;

  Vector<std::array<StringRefNull, 2>> defines_;
  /**
   * Name of other infos to recursively merge with this one.
   * No data slot must overlap otherwise we throw an error.
   */
  Vector<StringRefNull> additional_infos_;

  /* Transform feedback properties. */
  eGPUShaderTFBType tf_type_ = GPU_SHADER_TFB_NONE;
  Vector<const char *> tf_names_;

  /* Api-specific parameters. */
#ifdef WITH_METAL_BACKEND
  ushort mtl_max_threads_per_threadgroup_ = 0;
#endif

 public:
  ShaderCreateInfo(const char *name) : name_(name){};
  ~ShaderCreateInfo(){};

  using Self = ShaderCreateInfo;

  /* -------------------------------------------------------------------- */
  /** \name Shaders in/outs (fixed function pipeline config)
   * \{ */

  Self &vertex_in(int slot, Type type, StringRefNull name)
  {
    vertex_inputs_.append({slot, type, name});
    interface_names_size_ += name.size() + 1;
    return *(Self *)this;
  }

  Self &vertex_out(StageInterfaceInfo &interface)
  {
    vertex_out_interfaces_.append(&interface);
    return *(Self *)this;
  }

  Self &geometry_layout(PrimitiveIn prim_in,
                        PrimitiveOut prim_out,
                        int max_vertices,
                        int invocations = -1)
  {
    geometry_layout_.primitive_in = prim_in;
    geometry_layout_.primitive_out = prim_out;
    geometry_layout_.max_vertices = max_vertices;
    geometry_layout_.invocations = invocations;
    return *(Self *)this;
  }

  Self &local_group_size(int local_size_x, int local_size_y = 1, int local_size_z = 1)
  {
    compute_layout_.local_size_x = local_size_x;
    compute_layout_.local_size_y = local_size_y;
    compute_layout_.local_size_z = local_size_z;
    return *(Self *)this;
  }

  /**
   * Force fragment tests before fragment shader invocation.
   * IMPORTANT: This is incompatible with using the gl_FragDepth output.
   */
  Self &early_fragment_test(bool enable)
  {
    early_fragment_test_ = enable;
    return *(Self *)this;
  }

  /**
   * Only needed if geometry shader is enabled.
   * IMPORTANT: Input and output instance name will have respectively "_in" and "_out" suffix
   * appended in the geometry shader IF AND ONLY IF the vertex_out interface instance name matches
   * the geometry_out interface instance name.
   */
  Self &geometry_out(StageInterfaceInfo &interface)
  {
    geometry_out_interfaces_.append(&interface);
    return *(Self *)this;
  }

  Self &fragment_out(int slot,
                     Type type,
                     StringRefNull name,
                     DualBlend blend = DualBlend::NONE,
                     int raster_order_group = -1)
  {
    fragment_outputs_.append({slot, type, blend, name, raster_order_group});
    return *(Self *)this;
  }

  /**
   * Allows to fetch frame-buffer values from previous render sub-pass.
   *
   * On Apple Silicon, the additional `raster_order_group` is there to set the sub-pass
   * dependencies. Any sub-pass input need to have the same `raster_order_group` defined in the
   * shader writing them.
   *
   * IMPORTANT: Currently emulated on all backend except Metal. This is only for debugging purpose
   * as it is too slow to be viable.
   *
   * TODO(fclem): Vulkan can implement that using `subpassInput`. However sub-pass boundaries might
   * be difficult to inject implicitly and will require more high level changes.
   * TODO(fclem): OpenGL can emulate that using `GL_EXT_shader_framebuffer_fetch`.
   */
  Self &subpass_in(int slot, Type type, StringRefNull name, int raster_order_group = -1)
  {
    subpass_inputs_.append({slot, type, DualBlend::NONE, name, raster_order_group});
    return *(Self *)this;
  }

  /** \} */

  /* -------------------------------------------------------------------- */
  /** \name Shader specialization constants
   * \{ */

  /* Adds a specialization constant which is a dynamically modifiable value, which will be
   * statically compiled into a PSO configuration to provide optimal runtime performance,
   * with a reduced re-compilation cost vs Macro's with easier generation of unique permutations
   * based on run-time values.
   *
   * Tip: To evaluate use-cases of where specialization constants can provide a performance
   * gain, benchmark a given shader in its default case. Attempt to statically disable branches or
   * conditions which rely on uniform look-ups and measure if there is a marked improvement in
   * performance and/or reduction in memory bandwidth/register pressure.
   *
   * NOTE: Specialization constants will incur new compilation of PSOs and thus can incur an
   * unexpected cost. Specialization constants should be reserved for infrequently changing
   * parameters (e.g. user setting parameters such as toggling of features or quality level
   * presets), or those with a low set of possible runtime permutations.
   *
   * Specialization constants are assigned at runtime using:
   *  - `GPU_shader_constant_*(shader, name, value)`
   * or
   *  - `DrawPass::specialize_constant(shader, name, value)`
   *
   * All constants **MUST** be specified before binding a shader.
   */
  Self &specialization_constant(Type type, StringRefNull name, double default_value)
  {
    SpecializationConstant constant;
    constant.type = type;
    constant.name = name;
    switch (type) {
      case Type::INT:
        constant.value.i = static_cast<int>(default_value);
        break;
      case Type::BOOL:
      case Type::UINT:
        constant.value.u = static_cast<uint>(default_value);
        break;
      case Type::FLOAT:
        constant.value.f = static_cast<float>(default_value);
        break;
      default:
        BLI_assert_msg(0, "Only scalar types can be used as constants");
        break;
    }
    specialization_constants_.append(constant);
    interface_names_size_ += name.size() + 1;
    return *(Self *)this;
  }

  /* TODO: Add API to specify unique specialization config permutations in CreateInfo, allowing
   * specialized compilation to be primed and handled in the background at start-up, rather than
   * waiting for a given permutation to occur dynamically. */

  /** \} */

  /* -------------------------------------------------------------------- */
  /** \name Resources bindings points
   * \{ */

  Self &uniform_buf(int slot,
                    StringRefNull type_name,
                    StringRefNull name,
                    Frequency freq = Frequency::PASS)
  {
    Resource res(Resource::BindType::UNIFORM_BUFFER, slot);
    res.uniformbuf.name = name;
    res.uniformbuf.type_name = type_name;
    ((freq == Frequency::PASS) ? pass_resources_ : batch_resources_).append(res);
    interface_names_size_ += name.size() + 1;
    return *(Self *)this;
  }

  Self &storage_buf(int slot,
                    Qualifier qualifiers,
                    StringRefNull type_name,
                    StringRefNull name,
                    Frequency freq = Frequency::PASS)
  {
    Resource res(Resource::BindType::STORAGE_BUFFER, slot);
    res.storagebuf.qualifiers = qualifiers;
    res.storagebuf.type_name = type_name;
    res.storagebuf.name = name;
    ((freq == Frequency::PASS) ? pass_resources_ : batch_resources_).append(res);
    interface_names_size_ += name.size() + 1;
    return *(Self *)this;
  }

  Self &image(int slot,
              eGPUTextureFormat format,
              Qualifier qualifiers,
              ImageType type,
              StringRefNull name,
              Frequency freq = Frequency::PASS)
  {
    Resource res(Resource::BindType::IMAGE, slot);
    res.image.format = format;
    res.image.qualifiers = qualifiers;
    res.image.type = type;
    res.image.name = name;
    ((freq == Frequency::PASS) ? pass_resources_ : batch_resources_).append(res);
    interface_names_size_ += name.size() + 1;
    return *(Self *)this;
  }

  Self &sampler(int slot,
                ImageType type,
                StringRefNull name,
                Frequency freq = Frequency::PASS,
                GPUSamplerState sampler = GPUSamplerState::internal_sampler())
  {
    Resource res(Resource::BindType::SAMPLER, slot);
    res.sampler.type = type;
    res.sampler.name = name;
    /* Produces ASAN errors for the moment. */
    // res.sampler.sampler = sampler;
    UNUSED_VARS(sampler);
    ((freq == Frequency::PASS) ? pass_resources_ : batch_resources_).append(res);
    interface_names_size_ += name.size() + 1;
    return *(Self *)this;
  }

  /** \} */

  /* -------------------------------------------------------------------- */
  /** \name Shader Source
   * \{ */

  Self &vertex_source(StringRefNull filename)
  {
    vertex_source_ = filename;
    return *(Self *)this;
  }

  Self &geometry_source(StringRefNull filename)
  {
    geometry_source_ = filename;
    return *(Self *)this;
  }

  Self &fragment_source(StringRefNull filename)
  {
    fragment_source_ = filename;
    return *(Self *)this;
  }

  Self &compute_source(StringRefNull filename)
  {
    compute_source_ = filename;
    return *(Self *)this;
  }

  /** \} */

  /* -------------------------------------------------------------------- */
  /** \name Push constants
   *
   * Data managed by GPUShader. Can be set through uniform functions. Must be less than 128bytes.
   * \{ */

  Self &push_constant(Type type, StringRefNull name, int array_size = 0)
  {
    /* We don't have support for UINT push constants yet, use INT instead. */
    BLI_assert(type != Type::UINT);
    BLI_assert_msg(name.find("[") == -1,
                   "Array syntax is forbidden for push constants."
                   "Use the array_size parameter instead.");
    push_constants_.append({type, name, array_size});
    interface_names_size_ += name.size() + 1;
    return *(Self *)this;
  }

  /** \} */

  /* -------------------------------------------------------------------- */
  /** \name Defines
   * \{ */

  Self &define(StringRefNull name, StringRefNull value = "")
  {
    defines_.append({name, value});
    return *(Self *)this;
  }

  /** \} */

  /* -------------------------------------------------------------------- */
  /** \name Defines
   * \{ */

  Self &do_static_compilation(bool value)
  {
    do_static_compilation_ = value;
    return *(Self *)this;
  }

  Self &builtins(BuiltinBits builtin)
  {
    builtins_ |= builtin;
    return *(Self *)this;
  }

  /* Defines how the fragment shader will write to gl_FragDepth. */
  Self &depth_write(DepthWrite value)
  {
    depth_write_ = value;
    return *(Self *)this;
  }

  Self &auto_resource_location(bool value)
  {
    auto_resource_location_ = value;
    return *(Self *)this;
  }

  Self &legacy_resource_location(bool value)
  {
    legacy_resource_location_ = value;
    return *(Self *)this;
  }

  Self &metal_backend_only(bool flag)
  {
    metal_backend_only_ = flag;
    return *(Self *)this;
  }

  /** \} */

  /* -------------------------------------------------------------------- */
  /** \name Additional Create Info
   *
   * Used to share parts of the infos that are common to many shaders.
   * \{ */

  Self &additional_info(StringRefNull info_name)
  {
    additional_infos_.append(info_name);
    return *(Self *)this;
  }

  template<typename... Args> Self &additional_info(StringRefNull info_name, Args... args)
  {
    additional_info(info_name);
    additional_info(args...);
    return *(Self *)this;
  }

  /** \} */

  /* -------------------------------------------------------------------- */
  /** \name Typedef Sources
   *
   * Some resource declarations might need some special structure defined.
   * Adding a file using typedef_source will include it before the resource
   * and interface definitions.
   * \{ */

  Self &typedef_source(StringRefNull filename)
  {
    typedef_sources_.append(filename);
    return *(Self *)this;
  }

  /** \} */

  /* -------------------------------------------------------------------- */
  /** \name Transform feedback properties
   *
   * Transform feedback enablement and output binding assignment.
   * \{ */

  Self &transform_feedback_mode(eGPUShaderTFBType tf_mode)
  {
    BLI_assert(tf_mode != GPU_SHADER_TFB_NONE);
    tf_type_ = tf_mode;
    return *(Self *)this;
  }

  Self &transform_feedback_output_name(const char *name)
  {
    BLI_assert(tf_type_ != GPU_SHADER_TFB_NONE);
    tf_names_.append(name);
    return *(Self *)this;
  }
  /** \} */

  /* -------------------------------------------------------------------- */
  /** \name API-Specific Parameters
   *
   * Optional parameters exposed by specific back-ends to enable additional features and
   * performance tuning.
   * NOTE: These functions can be exposed as a pass-through on unsupported configurations.
   * \{ */

  /* \name mtl_max_total_threads_per_threadgroup
   * \a  max_total_threads_per_threadgroup - Provides compiler hint for maximum threadgroup size up
   * front. Maximum value is 1024. */
  Self &mtl_max_total_threads_per_threadgroup(ushort max_total_threads_per_threadgroup)
  {
#ifdef WITH_METAL_BACKEND
    mtl_max_threads_per_threadgroup_ = max_total_threads_per_threadgroup;
#else
    UNUSED_VARS(max_total_threads_per_threadgroup);
#endif
    return *(Self *)this;
  }

  /** \} */

  /* -------------------------------------------------------------------- */
  /** \name Recursive evaluation.
   *
   * Flatten all dependency so that this descriptor contains all the data from the additional
   * descriptors. This avoids tedious traversal in shader source creation.
   * \{ */

  /* WARNING: Recursive. */
  void finalize();

  std::string check_error() const;
  bool is_vulkan_compatible() const;

  /** Error detection that some backend compilers do not complain about. */
  void validate_merge(const ShaderCreateInfo &other_info);
  void validate_vertex_attributes(const ShaderCreateInfo *other_info = nullptr);

  /** \} */

  /* -------------------------------------------------------------------- */
  /** \name Operators.
   *
   * \{ */

  /* Comparison operator for GPUPass cache. We only compare if it will create the same shader
   * code. So we do not compare name and some other internal stuff. */
  bool operator==(const ShaderCreateInfo &b)
  {
    TEST_EQUAL(*this, b, builtins_);
    TEST_EQUAL(*this, b, vertex_source_generated);
    TEST_EQUAL(*this, b, fragment_source_generated);
    TEST_EQUAL(*this, b, compute_source_generated);
    TEST_EQUAL(*this, b, typedef_source_generated);
    TEST_VECTOR_EQUAL(*this, b, vertex_inputs_);
    TEST_EQUAL(*this, b, geometry_layout_);
    TEST_EQUAL(*this, b, compute_layout_);
    TEST_VECTOR_EQUAL(*this, b, fragment_outputs_);
    TEST_VECTOR_EQUAL(*this, b, pass_resources_);
    TEST_VECTOR_EQUAL(*this, b, batch_resources_);
    TEST_VECTOR_EQUAL(*this, b, vertex_out_interfaces_);
    TEST_VECTOR_EQUAL(*this, b, geometry_out_interfaces_);
    TEST_VECTOR_EQUAL(*this, b, push_constants_);
    TEST_VECTOR_EQUAL(*this, b, typedef_sources_);
    TEST_VECTOR_EQUAL(*this, b, subpass_inputs_);
    TEST_EQUAL(*this, b, vertex_source_);
    TEST_EQUAL(*this, b, geometry_source_);
    TEST_EQUAL(*this, b, fragment_source_);
    TEST_EQUAL(*this, b, compute_source_);
    TEST_VECTOR_EQUAL(*this, b, additional_infos_);
    TEST_VECTOR_EQUAL(*this, b, defines_);
    return true;
  }

  /** Debug print */
  friend std::ostream &operator<<(std::ostream &stream, const ShaderCreateInfo &info)
  {
    /* TODO(@fclem): Complete print. */

    auto print_resource = [&](const Resource &res) {
      switch (res.bind_type) {
        case Resource::BindType::UNIFORM_BUFFER:
          stream << "UNIFORM_BUFFER(" << res.slot << ", " << res.uniformbuf.name << ")"
                 << std::endl;
          break;
        case Resource::BindType::STORAGE_BUFFER:
          stream << "STORAGE_BUFFER(" << res.slot << ", " << res.storagebuf.name << ")"
                 << std::endl;
          break;
        case Resource::BindType::SAMPLER:
          stream << "SAMPLER(" << res.slot << ", " << res.sampler.name << ")" << std::endl;
          break;
        case Resource::BindType::IMAGE:
          stream << "IMAGE(" << res.slot << ", " << res.image.name << ")" << std::endl;
          break;
      }
    };

    /* TODO(@fclem): Order the resources. */
    for (auto &res : info.batch_resources_) {
      print_resource(res);
    }
    for (auto &res : info.pass_resources_) {
      print_resource(res);
    }
    return stream;
  }

  bool has_resource_type(Resource::BindType bind_type) const
  {
    for (auto &res : batch_resources_) {
      if (res.bind_type == bind_type) {
        return true;
      }
    }
    for (auto &res : pass_resources_) {
      if (res.bind_type == bind_type) {
        return true;
      }
    }
    return false;
  }

  bool has_resource_image() const
  {
    return has_resource_type(Resource::BindType::IMAGE);
  }

  /** \} */

#undef TEST_EQUAL
#undef TEST_VECTOR_EQUAL
};

}  // namespace blender::gpu::shader

namespace blender {
template<> struct DefaultHash<Vector<blender::gpu::shader::SpecializationConstant::Value>> {
  uint64_t operator()(const Vector<blender::gpu::shader::SpecializationConstant::Value> &key) const
  {
    uint64_t hash = 0;
    for (const blender::gpu::shader::SpecializationConstant::Value &value : key) {
      hash = hash * 33 ^ uint64_t(value.u);
    }
    return hash;
  }
};
}  // namespace blender
