RetroArch/gfx/drivers_shader/slang_reflection.h

/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2010-2017 - Hans-Kristian Arntzen
 * 
 *  RetroArch is free software: you can redistribute it and/or modify it under the terms
 *  of the GNU General Public License as published by the Free Software Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 *  PURPOSE.  See the GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef SLANG_REFLECTION_H_
#define SLANG_REFLECTION_H_

// Textures with built-in meaning.
enum slang_texture_semantic
{
   // The input texture to the filter chain.
   // Canonical name: "Original".
   SLANG_TEXTURE_SEMANTIC_ORIGINAL = 0,

   // The output from pass N - 1 if executing pass N, or ORIGINAL
   // if pass #0 is executed.
   // Canonical name: "Source".
   SLANG_TEXTURE_SEMANTIC_SOURCE = 1,

   // The original inputs with a history back in time.
   // Canonical name: "OriginalHistory#", e.g. "OriginalHistory2" <- Two frames back.
   // "OriginalHistory0" is an alias for SEMANTIC_ORIGINAL.
   // Size name: "OriginalHistorySize#".
   SLANG_TEXTURE_SEMANTIC_ORIGINAL_HISTORY = 2,

   // The output from pass #N, where pass #0 is the first pass.
   // Canonical name: "PassOutput#", e.g. "PassOutput3".
   // Size name: "PassOutputSize#".
   SLANG_TEXTURE_SEMANTIC_PASS_OUTPUT = 3,

   // The output from pass #N, one frame ago where pass #0 is the first pass.
   // It is not valid to use the pass feedback from a pass which is not offscreen.
   // Canonical name: "PassFeedback#", e.g. "PassFeedback2".
   SLANG_TEXTURE_SEMANTIC_PASS_FEEDBACK = 4,

   // Inputs from static textures, defined by the user.
   // There is no canonical name, and the only way to use these semantics are by
   // remapping.
   SLANG_TEXTURE_SEMANTIC_USER = 5,

   SLANG_NUM_TEXTURE_SEMANTICS,
   SLANG_INVALID_TEXTURE_SEMANTIC = -1
};

enum slang_semantic
{
   // mat4, MVP
   SLANG_SEMANTIC_MVP = 0,
   // vec4, viewport size of current pass
   SLANG_SEMANTIC_OUTPUT = 1,
   // vec4, viewport size of final pass
   SLANG_SEMANTIC_FINAL_VIEWPORT = 2,
   // uint, frame count with modulo
   SLANG_SEMANTIC_FRAME_COUNT = 3,   
   SLANG_NUM_BASE_SEMANTICS,

   // float, user defined parameter, arrayed
   SLANG_SEMANTIC_FLOAT_PARAMETER = 4,

   SLANG_NUM_SEMANTICS,
   SLANG_INVALID_SEMANTIC = -1
};

enum slang_stage
{
   SLANG_STAGE_VERTEX_MASK = 1 << 0,
   SLANG_STAGE_FRAGMENT_MASK = 1 << 1
};

enum slang_constant_buffer
{
   SLANG_CBUFFER_UBO = 0,
   SLANG_CBUFFER_PC,
   SLANG_CBUFFER_MAX,
};

/* Vulkan minimum limit. */
#define SLANG_NUM_BINDINGS 16

#ifdef __cplusplus

#include <string>
#include <unordered_map>
#include <stdint.h>
#include <spirv_cross.hpp>

struct slang_texture_semantic_meta
{
   size_t ubo_offset = 0;
   size_t push_constant_offset = 0;
   unsigned binding = 0;
   uint32_t stage_mask = 0;

   bool texture = false;
   bool uniform = false;
   bool push_constant = false;
};

struct slang_semantic_meta
{
   size_t ubo_offset = 0;
   size_t push_constant_offset = 0;
   unsigned num_components = 0;
   bool uniform = false;
   bool push_constant = false;
};

struct slang_texture_semantic_map
{
   slang_texture_semantic semantic;
   unsigned index;
};

struct slang_semantic_map
{
   slang_semantic semantic;
   unsigned index;
};

struct slang_reflection
{
   slang_reflection();

   size_t ubo_size = 0;
   size_t push_constant_size = 0;

   unsigned ubo_binding = 0;
   uint32_t ubo_stage_mask = 0;
   uint32_t push_constant_stage_mask = 0;

   std::vector<slang_texture_semantic_meta> semantic_textures[SLANG_NUM_TEXTURE_SEMANTICS];
   slang_semantic_meta semantics[SLANG_NUM_SEMANTICS];
   std::vector<slang_semantic_meta> semantic_float_parameters;

   const std::unordered_map<std::string, slang_texture_semantic_map> *texture_semantic_map = nullptr;
   const std::unordered_map<std::string, slang_texture_semantic_map> *texture_semantic_uniform_map = nullptr;
   const std::unordered_map<std::string, slang_semantic_map> *semantic_map = nullptr;
   unsigned pass_number = 0;
};

bool slang_reflect_spirv(const std::vector<uint32_t> &vertex,
      const std::vector<uint32_t> &fragment,
      slang_reflection *reflection);

bool slang_reflect(const spirv_cross::Compiler &vertex_compiler, const spirv_cross::Compiler &fragment_compiler,
      const spirv_cross::ShaderResources &vertex, const spirv_cross::ShaderResources &fragment,
      slang_reflection *reflection);

#endif
#endif