demotool/uniforms.hh

#pragma once
#ifndef REAL_BUILD
# include "externals.hh"
#endif


// Uniform types
enum class E_UniformType {
	F1 , F2 , F3 , F4 ,
	I1 , I2 , I3 , I4 ,
	SAMPLER2D
};

// Categories
enum class E_UniformCategory {
	FLOAT , INT ,
	SAMPLER2D ,
	__COUNT__
};

// Category from type
E_UniformCategory GetUniformCategory(
	__rd__ const E_UniformType type );
// Element count from type
uint32_t GetElementCount(
	__rd__ const E_UniformType type );
// Is some category a vector type?
bool IsVectorCategory(
	__rd__ const E_UniformCategory category );


// Uniform declarations
struct T_UniformDeclaration
{
	std::string name;
	bool global;
	E_UniformType type;

	std::string source;
	uint32_t line;
};

using T_UniformDeclarations = std::unordered_map< std::string , T_UniformDeclaration >;


/*============================================================================*/

// Packed uniforms
struct T_PackedUniforms
{
	uint32_t elements = 0;
	std::map< std::string , uint32_t > positions;
};

T_PackedUniforms PackUniforms(
	__rd__ T_UniformDeclarations const& declarations ,
	__rd__ const E_UniformCategory category );


// A set of uniforms, meant for use with a buffer or directly
struct T_UniformSet
{
	static constexpr uint32_t Invalid = 0xffffffff;

	T_UniformSet( );
	explicit T_UniformSet(
		__rw__ T_UniformDeclarations uniforms );

	DEF_MOVE( T_UniformSet );
	NO_COPY( T_UniformSet );

	// ---------------------------------------------------------------------

	T_UniformDeclarations const& declarations( ) const noexcept
		{ return declarations_; }

	uint32_t vectorElements( ) const noexcept
		{ return vectorElements_; }
	uint32_t opaqueElements( ) const noexcept
		{ return opaqueElements_; }

	uint32_t inCategory(
		__rd__ const E_UniformCategory category ) const noexcept
	{
		assert( category != E_UniformCategory::__COUNT__ );
		return packed_[ int( category ) ].elements;
	}

	// Return the position of the specified uniform in its category.
	// If the uniform doesn't exist, this will return Invalid.
	uint32_t position(
		__rd__ std::string const& uniform ) const;

    private:
	T_UniformDeclarations declarations_;
	uint32_t vectorElements_ , opaqueElements_;
	T_PackedUniforms packed_[ int( E_UniformCategory::__COUNT__ ) ];
};


/*============================================================================*/

struct T_UniformStorage
{
	T_UniformStorage( ) = delete;
	NO_COPY( T_UniformStorage );
	DEF_MOVE( T_UniformStorage );

	explicit T_UniformStorage(
		__rw__ T_UniformSet&& uniforms );

	float* getf(
		__rd__ std::string const& name );
	int* geti(
		__rd__ std::string const& name );

    protected:
	T_UniformSet uniforms_;
	uint32_t starts_[ int( E_UniformCategory::__COUNT__ ) ];
	std::vector< int > values_;
};

struct T_ProgramUniforms : public T_UniformStorage
{
	T_ProgramUniforms( ) = delete;
	NO_COPY( T_ProgramUniforms );
	DEF_MOVE( T_ProgramUniforms );

	explicit T_ProgramUniforms(
		__rw__ T_UniformSet uniforms );

	void apply(
		__rd__ const GLuint id );
};

struct T_UniformBuffer : public T_UniformStorage
{
	T_UniformBuffer( ) = delete;
	NO_COPY( T_UniformBuffer );

	explicit T_UniformBuffer(
		__rw__ T_UniformSet uniforms );
	MOVE( T_UniformBuffer );
	~T_UniformBuffer( );

	void update( );
	void bindTo(
		__rd__ const GLuint binding );

    private:
	GLuint buffer_;
};