texture.h

/*
    This file is part of OpenGL-StarterPack (GLSP), an open source OpenGL based framework
    that facilitates and speeds up demo and project creation by offering an abstraction to
    the basic objects of OpenGL as well as incluing the necessary libraries.

    MIT License

    Copyright (c) 2024 Antonio Espinosa Garcia

*/
#ifndef __TEXTURE__
#define __TEXTURE__

#include <GLSP/core.h>
#include <GLSP/shader.h>
#include <GLSP/utils.h>

GLSP_NAMESPACE_BEGIN

/*
Stores all data needed to configure a texture object
*/
struct TextureConfig
{
    TextureType type{TEXTURE_2D};
    unsigned int samples{1};
    unsigned int layers{1};

    unsigned int format{GL_RGBA};
    int internalFormat{GL_RGBA8};
    unsigned int dataType{GL_UNSIGNED_BYTE};

    int level{0};
    int border{0};

    bool anisotropicFilter{true};
    float anisotopicFilterValue{16.0f};

    bool useMipmaps{true};
    int magFilter{GL_LINEAR};
    int minFilter{GL_LINEAR_MIPMAP_LINEAR};

    int wrapT{GL_REPEAT};
    int wrapS{GL_REPEAT};
    int wrapR{GL_REPEAT};

    glm::vec4 borderColor{glm::vec4(0.0f)};

    bool freeImageCacheOnGenerate{true};
};

/*
Stores image data
*/
struct Image
{
    std::string path{""};

    unsigned char *data{nullptr};
    float *HDRdata{nullptr};
    Extent2D extent{0, 0}; // Does not need to corresoong with texture extent;

    bool linear{true};
    int channels{0};

    bool panorama{false};
};

/*
Wrapper of the OpenGL texture object.
*/
class Texture
{
protected:
    unsigned int m_id;

    Extent2D m_extent{};

    TextureConfig m_config{};

    Image m_image{};

    bool m_generated{false};

    void setup();

    /*
   Utily function in case a panorama image is loaded. It converts it to a usable cubemap format.
   */
    void panorama_to_cubemap();

    static Shader *HDRIConverterShader;
    static Shader *IrradianceComputeShader;

public:
    Texture(Extent2D extent) : m_extent(extent) {}
    Texture(Extent2D extent, TextureConfig config) : m_extent(extent), m_config(config) {}
    Texture(TextureConfig config) : m_config(config) {}
    Texture() {}
    ~Texture() { cleanup(); }

    void generate();

    inline unsigned int get_id() const { return m_id; }

    inline Image get_image() const { return m_image; }
    inline void set_image(Image img) { m_image = img; }

    inline Extent2D get_extent() const { return m_extent; }
    void set_extent(Extent2D extent);

    inline TextureConfig get_config() const { return m_config; }

    inline void set_config(TextureConfig config) { m_config = config; }

    virtual void bind(unsigned int slot = 0) const;

    virtual void unbind() const;

    virtual void resize(Extent2D extent);

    inline bool is_generated() const { return m_generated; }

    inline void cleanup() { GL_CHECK(glDeleteTextures(1, &m_id)); }

    void generate_mipmaps();

    Texture *compute_irradiance(int resolution = 32);
};

GLSP_NAMESPACE_END

#endif