text: //
  // Copyright (c) 2002-2013 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  #ifndef _COMPILER_INTERFACE_INCLUDED_
  #define _COMPILER_INTERFACE_INCLUDED_
  
  #if defined(COMPONENT_BUILD) && !defined(ANGLE_TRANSLATOR_STATIC)
  #if defined(_WIN32) || defined(_WIN64)
  
  #if defined(ANGLE_TRANSLATOR_IMPLEMENTATION)
  #define COMPILER_EXPORT __declspec(dllexport)
  #else
  #define COMPILER_EXPORT __declspec(dllimport)
  #endif  // defined(ANGLE_TRANSLATOR_IMPLEMENTATION)
  
  #else  // defined(_WIN32) || defined(_WIN64)
  #define COMPILER_EXPORT __attribute__((visibility("default")))
  #endif
  
  #else  // defined(COMPONENT_BUILD) && !defined(ANGLE_TRANSLATOR_STATIC)
  #define COMPILER_EXPORT
  #endif
  
  #include <stddef.h>
  
  #include "KHR/khrplatform.h"
  
  //
  // This is the platform independent interface between an OGL driver
  // and the shading language compiler.
  //
  
  namespace sh
  {
  // GLenum alias
  typedef unsigned int GLenum;
  }
  
  // Must be included after GLenum proxy typedef
  // Note: make sure to increment ANGLE_SH_VERSION when changing ShaderVars.h
  #include "ShaderVars.h"
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  // Version number for shader translation API.
  // It is incremented every time the API changes.
  #define ANGLE_SH_VERSION 130
  
  typedef enum {
    SH_GLES2_SPEC = 0x8B40,
    SH_WEBGL_SPEC = 0x8B41,
  
    // The CSS Shaders spec is a subset of the WebGL spec.
    //
    // In both CSS vertex and fragment shaders, ANGLE:
    // (1) Reserves the "css_" prefix.
    // (2) Renames the main function to css_main.
    // (3) Disables the gl_MaxDrawBuffers built-in.
    //
    // In CSS fragment shaders, ANGLE:
    // (1) Disables the gl_FragColor built-in.
    // (2) Disables the gl_FragData built-in.
    // (3) Enables the css_MixColor built-in.
    // (4) Enables the css_ColorMatrix built-in.
    //
    // After passing a CSS shader through ANGLE, the browser is expected to append
    // a new main function to it.
    // This new main function will call the css_main function.
    // It may also perform additional operations like varying assignment, texture
    // access, and gl_FragColor assignment in order to implement the CSS Shaders
    // blend modes.
    //
    SH_CSS_SHADERS_SPEC = 0x8B42
  } ShShaderSpec;
  
  typedef enum {
    SH_ESSL_OUTPUT   = 0x8B45,
    SH_GLSL_OUTPUT   = 0x8B46,
    SH_HLSL_OUTPUT   = 0x8B47,
    SH_HLSL9_OUTPUT  = 0x8B47,
    SH_HLSL11_OUTPUT = 0x8B48
  } ShShaderOutput;
  
  typedef enum {
    SH_PRECISION_HIGHP     = 0x5001,
    SH_PRECISION_MEDIUMP   = 0x5002,
    SH_PRECISION_LOWP      = 0x5003,
    SH_PRECISION_UNDEFINED = 0
  } ShPrecisionType;
  
  typedef enum {
    SH_INFO_LOG_LENGTH                = 0x8B84,
    SH_OBJECT_CODE_LENGTH             = 0x8B88,  // GL_SHADER_SOURCE_LENGTH
    SH_ACTIVE_UNIFORMS                = 0x8B86,
    SH_ACTIVE_UNIFORM_MAX_LENGTH      = 0x8B87,
    SH_ACTIVE_ATTRIBUTES              = 0x8B89,
    SH_ACTIVE_ATTRIBUTE_MAX_LENGTH    = 0x8B8A,
    SH_VARYINGS                       = 0x8BBB,
    SH_VARYING_MAX_LENGTH             = 0x8BBC,
    SH_MAPPED_NAME_MAX_LENGTH         = 0x6000,
    SH_NAME_MAX_LENGTH                = 0x6001,
    SH_HASHED_NAME_MAX_LENGTH         = 0x6002,
    SH_HASHED_NAMES_COUNT             = 0x6003,
    SH_SHADER_VERSION                 = 0x6004,
    SH_RESOURCES_STRING_LENGTH        = 0x6005,
    SH_OUTPUT_TYPE                    = 0x6006
  } ShShaderInfo;
  
  // Compile options.
  typedef enum {
    SH_VALIDATE                = 0,
    SH_VALIDATE_LOOP_INDEXING  = 0x0001,
    SH_INTERMEDIATE_TREE       = 0x0002,
    SH_OBJECT_CODE             = 0x0004,
    SH_VARIABLES               = 0x0008,
    SH_LINE_DIRECTIVES         = 0x0010,
    SH_SOURCE_PATH             = 0x0020,
    SH_UNROLL_FOR_LOOP_WITH_INTEGER_INDEX = 0x0040,
    // If a sampler array index happens to be a loop index,
    //   1) if its type is integer, unroll the loop.
    //   2) if its type is float, fail the shader compile.
    // This is to work around a mac driver bug.
    SH_UNROLL_FOR_LOOP_WITH_SAMPLER_ARRAY_INDEX = 0x0080,
  
    // This is needed only as a workaround for certain OpenGL driver bugs.
    SH_EMULATE_BUILT_IN_FUNCTIONS = 0x0100,
  
    // This is an experimental flag to enforce restrictions that aim to prevent 
    // timing attacks.
    // It generates compilation errors for shaders that could expose sensitive
    // texture information via the timing channel.
    // To use this flag, you must compile the shader under the WebGL spec
    // (using the SH_WEBGL_SPEC flag).
    SH_TIMING_RESTRICTIONS = 0x0200,
  
    // This flag prints the dependency graph that is used to enforce timing
    // restrictions on fragment shaders.
    // This flag only has an effect if all of the following are true:
    // - The shader spec is SH_WEBGL_SPEC.
    // - The compile options contain the SH_TIMING_RESTRICTIONS flag.
    // - The shader type is GL_FRAGMENT_SHADER.
    SH_DEPENDENCY_GRAPH = 0x0400,
  
    // Enforce the GLSL 1.017 Appendix A section 7 packing restrictions.
    // This flag only enforces (and can only enforce) the packing
    // restrictions for uniform variables in both vertex and fragment
    // shaders. ShCheckVariablesWithinPackingLimits() lets embedders
    // enforce the packing restrictions for varying variables during
    // program link time.
    SH_ENFORCE_PACKING_RESTRICTIONS = 0x0800,
  
    // This flag ensures all indirect (expression-based) array indexing
    // is clamped to the bounds of the array. This ensures, for example,
    // that you cannot read off the end of a uniform, whether an array
    // vec234, or mat234 type. The ShArrayIndexClampingStrategy enum,
    // specified in the ShBuiltInResources when constructing the
    // compiler, selects the strategy for the clamping implementation.
    SH_CLAMP_INDIRECT_ARRAY_BOUNDS = 0x1000,
  
    // This flag limits the complexity of an expression.
    SH_LIMIT_EXPRESSION_COMPLEXITY = 0x2000,
  
    // This flag limits the depth of the call stack.
    SH_LIMIT_CALL_STACK_DEPTH = 0x4000,
  
    // This flag initializes gl_Position to vec4(0,0,0,0) at the
    // beginning of the vertex shader's main(), and has no effect in the
    // fragment shader. It is intended as a workaround for drivers which
    // incorrectly fail to link programs if gl_Position is not written.
    SH_INIT_GL_POSITION = 0x8000,
  
    // This flag replaces
    //   "a && b" with "a ? b : false",
    //   "a || b" with "a ? true : b".
    // This is to work around a MacOSX driver bug that |b| is executed
    // independent of |a|'s value.
    SH_UNFOLD_SHORT_CIRCUIT = 0x10000,
  
    // This flag initializes varyings without static use in vertex shader
    // at the beginning of main(), and has no effects in the fragment shader.
    // It is intended as a workaround for drivers which incorrectly optimize
    // out such varyings and cause a link failure.
    SH_INIT_VARYINGS_WITHOUT_STATIC_USE = 0x20000,
  
    // This flag scalarizes vec/ivec/bvec/mat constructor args.
    // It is intended as a workaround for Linux/Mac driver bugs.
    SH_SCALARIZE_VEC_AND_MAT_CONSTRUCTOR_ARGS = 0x40000,
  
    // This flag overwrites a struct name with a unique prefix.
    // It is intended as a workaround for drivers that do not handle
    // struct scopes correctly, including all Mac drivers and Linux AMD.
    SH_REGENERATE_STRUCT_NAMES = 0x80000,
  } ShCompileOptions;
  
  // Defines alternate strategies for implementing array index clamping.
  typedef enum {
    // Use the clamp intrinsic for array index clamping.
    SH_CLAMP_WITH_CLAMP_INTRINSIC = 1,
  
    // Use a user-defined function for array index clamping.
    SH_CLAMP_WITH_USER_DEFINED_INT_CLAMP_FUNCTION
  } ShArrayIndexClampingStrategy;
  
  //
  // Driver must call this first, once, before doing any other
  // compiler operations.
  // If the function succeeds, the return value is nonzero, else zero.
  //
  COMPILER_EXPORT int ShInitialize();
  //
  // Driver should call this at shutdown.
  // If the function succeeds, the return value is nonzero, else zero.
  //
  COMPILER_EXPORT int ShFinalize();
  
  // The 64 bits hash function. The first parameter is the input string; the
  // second parameter is the string length.
  typedef khronos_uint64_t (*ShHashFunction64)(const char*, size_t);
  
  //
  // Implementation dependent built-in resources (constants and extensions).
  // The names for these resources has been obtained by stripping gl_/GL_.
  //
  typedef struct
  {
      // Constants.
      int MaxVertexAttribs;
      int MaxVertexUniformVectors;
      int MaxVaryingVectors;
      int MaxVertexTextureImageUnits;
      int MaxCombinedTextureImageUnits;
      int MaxTextureImageUnits;
      int MaxFragmentUniformVectors;
      int MaxDrawBuffers;
  
      // Extensions.
      // Set to 1 to enable the extension, else 0.
      int OES_standard_derivatives;
      int OES_EGL_image_external;
      int ARB_texture_rectangle;
      int EXT_draw_buffers;
      int EXT_frag_depth;
      int EXT_shader_texture_lod;
  
      // Set to 1 if highp precision is supported in the fragment language.
      // Default is 0.
      int FragmentPrecisionHigh;
  
      // GLSL ES 3.0 constants.
      int MaxVertexOutputVectors;
      int MaxFragmentInputVectors;
      int MinProgramTexelOffset;
      int MaxProgramTexelOffset;
  
      // Name Hashing.
      // Set a 64 bit hash function to enable user-defined name hashing.
      // Default is NULL.
      ShHashFunction64 HashFunction;
  
      // Selects a strategy to use when implementing array index clamping.
      // Default is SH_CLAMP_WITH_CLAMP_INTRINSIC.
      ShArrayIndexClampingStrategy ArrayIndexClampingStrategy;
  
      // The maximum complexity an expression can be.
      int MaxExpressionComplexity;
  
      // The maximum depth a call stack can be.
      int MaxCallStackDepth;
  } ShBuiltInResources;
  
  //
  // Initialize built-in resources with minimum expected values.
  //
  COMPILER_EXPORT void ShInitBuiltInResources(ShBuiltInResources* resources);
  
  //
  // ShHandle held by but opaque to the driver.  It is allocated,
  // managed, and de-allocated by the compiler. Its contents
  // are defined by and used by the compiler.
  //
  // If handle creation fails, 0 will be returned.
  //
  typedef void* ShHandle;
  
  //
  // Returns the a concatenated list of the items in ShBuiltInResources as a string.
  // This function must be updated whenever ShBuiltInResources is changed.
  // Parameters:
  // handle: Specifies the handle of the compiler to be used.
  // outStringLen: Specifies the size of the buffer, in number of characters. The size
  //               of the buffer required to store the resources string can be obtained
  //               by calling ShGetInfo with SH_RESOURCES_STRING_LENGTH.
  // outStr: Returns a null-terminated string representing all the built-in resources.
  COMPILER_EXPORT void ShGetBuiltInResourcesString(const ShHandle handle, size_t outStringLen, char *outStr);
  
  //
  // Driver calls these to create and destroy compiler objects.
  //
  // Returns the handle of constructed compiler, null if the requested compiler is
  // not supported.
  // Parameters:
  // type: Specifies the type of shader - GL_FRAGMENT_SHADER or GL_VERTEX_SHADER.
  // spec: Specifies the language spec the compiler must conform to -
  //       SH_GLES2_SPEC or SH_WEBGL_SPEC.
  // output: Specifies the output code type - SH_ESSL_OUTPUT, SH_GLSL_OUTPUT,
  //         SH_HLSL9_OUTPUT or SH_HLSL11_OUTPUT.
  // resources: Specifies the built-in resources.
  COMPILER_EXPORT ShHandle ShConstructCompiler(
      sh::GLenum type,
      ShShaderSpec spec,
      ShShaderOutput output,
      const ShBuiltInResources* resources);
  COMPILER_EXPORT void ShDestruct(ShHandle handle);
  
  //
  // Compiles the given shader source.
  // If the function succeeds, the return value is nonzero, else zero.
  // Parameters:
  // handle: Specifies the handle of compiler to be used.
  // shaderStrings: Specifies an array of pointers to null-terminated strings
  //                containing the shader source code.
  // numStrings: Specifies the number of elements in shaderStrings array.
  // compileOptions: A mask containing the following parameters:
  // SH_VALIDATE: Validates shader to ensure that it conforms to the spec
  //              specified during compiler construction.
  // SH_VALIDATE_LOOP_INDEXING: Validates loop and indexing in the shader to
  //                            ensure that they do not exceed the minimum
  //                            functionality mandated in GLSL 1.0 spec,
  //                            Appendix A, Section 4 and 5.
  //                            There is no need to specify this parameter when
  //                            compiling for WebGL - it is implied.
  // SH_INTERMEDIATE_TREE: Writes intermediate tree to info log.
  //                       Can be queried by calling ShGetInfoLog().
  // SH_OBJECT_CODE: Translates intermediate tree to glsl or hlsl shader.
  //                 Can be queried by calling ShGetObjectCode().
  // SH_VARIABLES: Extracts attributes, uniforms, and varyings.
  //               Can be queried by calling ShGetVariableInfo().
  //
  COMPILER_EXPORT int ShCompile(
      const ShHandle handle,
      const char* const shaderStrings[],
      size_t numStrings,
      int compileOptions
      );
  
  // Returns a parameter from a compiled shader.
  // Parameters:
  // handle: Specifies the compiler
  // pname: Specifies the parameter to query.
  // The following parameters are defined:
  // SH_INFO_LOG_LENGTH: the number of characters in the information log
  //                     including the null termination character.
  // SH_OBJECT_CODE_LENGTH: the number of characters in the object code
  //                        including the null termination character.
  // SH_ACTIVE_ATTRIBUTES: the number of active attribute variables.
  // SH_ACTIVE_ATTRIBUTE_MAX_LENGTH: the length of the longest active attribute
  //                                 variable name including the null
  //                                 termination character.
  // SH_ACTIVE_UNIFORMS: the number of active uniform variables.
  // SH_ACTIVE_UNIFORM_MAX_LENGTH: the length of the longest active uniform
  //                               variable name including the null
  //                               termination character.
  // SH_VARYINGS: the number of varying variables.
  // SH_VARYING_MAX_LENGTH: the length of the longest varying variable name
  //                        including the null termination character.
  // SH_MAPPED_NAME_MAX_LENGTH: the length of the mapped variable name including
  //                            the null termination character.
  // SH_NAME_MAX_LENGTH: the max length of a user-defined name including the
  //                     null termination character.
  // SH_HASHED_NAME_MAX_LENGTH: the max length of a hashed name including the
  //                            null termination character.
  // SH_HASHED_NAMES_COUNT: the number of hashed names from the latest compile.
  // SH_SHADER_VERSION: the version of the shader language
  // SH_OUTPUT_TYPE: the currently set language output type
  //
  // params: Requested parameter
  COMPILER_EXPORT void ShGetInfo(const ShHandle handle,
                                 ShShaderInfo pname,
                                 size_t* params);
  
  // Returns nul-terminated information log for a compiled shader.
  // Parameters:
  // handle: Specifies the compiler
  // infoLog: Specifies an array of characters that is used to return
  //          the information log. It is assumed that infoLog has enough memory
  //          to accomodate the information log. The size of the buffer required
  //          to store the returned information log can be obtained by calling
  //          ShGetInfo with SH_INFO_LOG_LENGTH.
  COMPILER_EXPORT void ShGetInfoLog(const ShHandle handle, char* infoLog);
  
  // Returns null-terminated object code for a compiled shader.
  // Parameters:
  // handle: Specifies the compiler
  // infoLog: Specifies an array of characters that is used to return
  //          the object code. It is assumed that infoLog has enough memory to
  //          accomodate the object code. The size of the buffer required to
  //          store the returned object code can be obtained by calling
  //          ShGetInfo with SH_OBJECT_CODE_LENGTH.
  COMPILER_EXPORT void ShGetObjectCode(const ShHandle handle, char* objCode);
  
  // Returns information about a shader variable.
  // Parameters:
  // handle: Specifies the compiler
  // variableType: Specifies the variable type; options include
  //               SH_ACTIVE_ATTRIBUTES, SH_ACTIVE_UNIFORMS, SH_VARYINGS.
  // index: Specifies the index of the variable to be queried.
  // length: Returns the number of characters actually written in the string
  //         indicated by name (excluding the null terminator) if a value other
  //         than NULL is passed.
  // size: Returns the size of the variable.
  // type: Returns the data type of the variable.
  // precision: Returns the precision of the variable.
  // staticUse: Returns 1 if the variable is accessed in a statement after
  //            pre-processing, whether or not run-time flow of control will
  //            cause that statement to be executed.
  //            Returns 0 otherwise.
  // name: Returns a null terminated string containing the name of the
  //       variable. It is assumed that name has enough memory to accormodate
  //       the variable name. The size of the buffer required to store the
  //       variable name can be obtained by calling ShGetInfo with
  //       SH_ACTIVE_ATTRIBUTE_MAX_LENGTH, SH_ACTIVE_UNIFORM_MAX_LENGTH,
  //       SH_VARYING_MAX_LENGTH.
  // mappedName: Returns a null terminated string containing the mapped name of
  //             the variable, It is assumed that mappedName has enough memory
  //             (SH_MAPPED_NAME_MAX_LENGTH), or NULL if don't care about the
  //             mapped name. If the name is not mapped, then name and mappedName
  //             are the same.
  COMPILER_EXPORT void ShGetVariableInfo(const ShHandle handle,
                                         ShShaderInfo variableType,
                                         int index,
                                         size_t* length,
                                         int* size,
                                         sh::GLenum* type,
                                         ShPrecisionType* precision,
                                         int* staticUse,
                                         char* name,
                                         char* mappedName);
  
  // Returns information about a name hashing entry from the latest compile.
  // Parameters:
  // handle: Specifies the compiler
  // index: Specifies the index of the name hashing entry to be queried.
  // name: Returns a null terminated string containing the user defined name.
  //       It is assumed that name has enough memory to accomodate the name.
  //       The size of the buffer required to store the user defined name can
  //       be obtained by calling ShGetInfo with SH_NAME_MAX_LENGTH.
  // hashedName: Returns a null terminated string containing the hashed name of
  //             the uniform variable, It is assumed that hashedName has enough
  //             memory to accomodate the name. The size of the buffer required
  //             to store the name can be obtained by calling ShGetInfo with
  //             SH_HASHED_NAME_MAX_LENGTH.
  COMPILER_EXPORT void ShGetNameHashingEntry(const ShHandle handle,
                                             int index,
                                             char* name,
                                             char* hashedName);
  
  // Shader variable inspection.
  // Returns a pointer to a list of variables of the designated type.
  // (See ShaderVars.h for type definitions, included above)
  // Returns NULL on failure.
  // Parameters:
  // handle: Specifies the compiler
  COMPILER_EXPORT const std::vector<sh::Uniform> *ShGetUniforms(const ShHandle handle);
  COMPILER_EXPORT const std::vector<sh::Varying> *ShGetVaryings(const ShHandle handle);
  COMPILER_EXPORT const std::vector<sh::Attribute> *ShGetAttributes(const ShHandle handle);
  COMPILER_EXPORT const std::vector<sh::Attribute> *ShGetOutputVariables(const ShHandle handle);
  COMPILER_EXPORT const std::vector<sh::InterfaceBlock> *ShGetInterfaceBlocks(const ShHandle handle);
  
  typedef struct
  {
      sh::GLenum type;
      int size;
  } ShVariableInfo;
  
  // Returns 1 if the passed in variables pack in maxVectors following
  // the packing rules from the GLSL 1.017 spec, Appendix A, section 7.
  // Returns 0 otherwise. Also look at the SH_ENFORCE_PACKING_RESTRICTIONS
  // flag above.
  // Parameters:
  // maxVectors: the available rows of registers.
  // varInfoArray: an array of variable info (types and sizes).
  // varInfoArraySize: the size of the variable array.
  COMPILER_EXPORT int ShCheckVariablesWithinPackingLimits(
      int maxVectors,
      ShVariableInfo* varInfoArray,
      size_t varInfoArraySize);
  
  // Gives the compiler-assigned register for an interface block.
  // The method writes the value to the output variable "indexOut".
  // Returns true if it found a valid interface block, false otherwise.
  // Parameters:
  // handle: Specifies the compiler
  // interfaceBlockName: Specifies the interface block
  // indexOut: output variable that stores the assigned register
  COMPILER_EXPORT bool ShGetInterfaceBlockRegister(const ShHandle handle,
                                                   const char *interfaceBlockName,
                                                   unsigned int *indexOut);
  
  // Gives the compiler-assigned register for uniforms in the default
  // interface block.
  // The method writes the value to the output variable "indexOut".
  // Returns true if it found a valid default uniform, false otherwise.
  // Parameters:
  // handle: Specifies the compiler
  // interfaceBlockName: Specifies the uniform
  // indexOut: output variable that stores the assigned register
  COMPILER_EXPORT bool ShGetUniformRegister(const ShHandle handle,
                                            const char *uniformName,
                                            unsigned int *indexOut);
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif // _COMPILER_INTERFACE_INCLUDED_
  