state.h

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#pragma once
 
#include "eu/render/constants.h"
 
#include <optional>
 
namespace eu::render
{

 
 

// Forward declaration
struct FrameBuffer;
struct TextureCubemap;
struct Texture2d;
struct Uniform;
 
 

// Enums
 
enum class Blend
{
    zero,
    one,
    src_color,
    one_minus_src_color,
    dst_color,
    one_minus_dst_color,
    src_alpha,
    one_minus_src_alpha,
    dst_alpha,
    one_minus_dst_alpha,
    constant_color,
    one_minus_constant_color,
    constant_alpha,
    one_minus_constant_alpha,
    src_alpha_saturate,
    src1_color,
    one_minus_src1_color,
    src1_alpha,
    one_minus_src1_alpha
};
 
enum class Compare
{
    always,
    never,
    less,
    equal,
    less_equal,
    greater,
    not_equal,
    greater_equal
};
 
enum class CullFace
{
    front,
    back,
    front_and_back
};
 
enum class RenderMode
{
    fill,
    line,
    point
};
 
enum class StencilAction
{
    keep,
    zero,
    replace,
    increase,
    increase_wrap,
    decrease,
    decrease_wrap,
    invert
};
 
 

// Alias

using BlendMode = std::tuple<Blend, Blend>;

using StencilFunc = std::tuple<Compare, i32, u32>;

using StencilOp = std::tuple<StencilAction, StencilAction, StencilAction>;
 
 

// State

struct State
{
    std::optional<bool> cull_face;
    std::optional<CullFace> cull_face_mode;
 
    std::optional<bool> blending;
    std::optional<BlendMode> blend_mode;
 
    std::optional<bool> depth_test;
    std::optional<bool> depth_mask;
    std::optional<Compare> depth_func;
 
    std::optional<bool> stencil_test;
    std::optional<u32> stencil_mask;
 
    std::optional<RenderMode> render_mode;
    std::optional<StencilFunc> stencil_func;
    std::optional<StencilOp> stencil_op;
 
    std::optional<int> active_texture;
    std::array<std::optional<unsigned int>, kk::max_textures_supported> texture_bound;
};
 
 

// Changer

struct StateChanger
{
    State* states;
 
    explicit StateChanger(State* s);
 
    StateChanger& cull_face(bool new_state);
    StateChanger& blending(bool new_state);
    StateChanger& depth_test(bool new_state);
    StateChanger& depth_mask(bool new_state);
    StateChanger& depth_func(Compare new_state);
    StateChanger& stencil_test(bool new_state);

    StateChanger& stencil_mask(u32 new_state);

    StateChanger& stencil_func(Compare func, i32 ref, u32 mask);
    StateChanger& render_mode(RenderMode new_state);

    StateChanger& stencil_op(StencilAction stencil_fail, StencilAction depth_fail, StencilAction pass);
    StateChanger& cull_face_mode(CullFace new_state);
    StateChanger& blend_mode(Blend src, Blend dst);
    StateChanger& activate_texture(int new_texture);
    StateChanger& bind_texture_2d(int slot, unsigned int texture);
    StateChanger& bind_texture_cubemap(int slot, unsigned int texture);
};
 
void bind_texture_2d(State* states, const Uniform& uniform, const Texture2d& texture);
void bind_texture_2d(State* states, const Uniform& uniform, const FrameBuffer& texture);
void bind_texture_cubemap(State* states, const Uniform& uniform, const TextureCubemap& texture);

 
}  //  namespace eu::render