XCEngine/engine/src/RHI/OpenGL/OpenGLTexture.cpp

#include "XCEngine/RHI/OpenGL/OpenGLTexture.h"
#include <glad/glad.h>
#include <stb_image.h>
#include <iostream>

namespace XCEngine {
namespace RHI {

static unsigned int ToGLTextureTarget(OpenGLTextureType type) {
    switch (type) {
        case OpenGLTextureType::Texture1D: return GL_TEXTURE_1D;
        case OpenGLTextureType::Texture2D: return GL_TEXTURE_2D;
        case OpenGLTextureType::Texture2DArray: return GL_TEXTURE_2D_ARRAY;
        case OpenGLTextureType::Texture3D: return GL_TEXTURE_3D;
        case OpenGLTextureType::TextureCube: return GL_TEXTURE_CUBE_MAP;
        case OpenGLTextureType::TextureCubeArray: return GL_TEXTURE_CUBE_MAP_ARRAY;
        default: return GL_TEXTURE_2D;
    }
}

static void ToGLFormat(OpenGLFormat fmt, unsigned int& internalFormat, unsigned int& glFormat, unsigned int& glType) {
    switch (fmt) {
        case OpenGLFormat::R8:
            internalFormat = GL_R8; glFormat = GL_RED; glType = GL_UNSIGNED_BYTE;
            break;
        case OpenGLFormat::RG8:
            internalFormat = GL_RG8; glFormat = GL_RG; glType = GL_UNSIGNED_BYTE;
            break;
        case OpenGLFormat::RGBA8:
            internalFormat = GL_RGBA8; glFormat = GL_RGBA; glType = GL_UNSIGNED_BYTE;
            break;
        case OpenGLFormat::RGBA16F:
            internalFormat = GL_RGBA16F; glFormat = GL_RGBA; glType = GL_HALF_FLOAT;
            break;
        case OpenGLFormat::RGBA32F:
            internalFormat = GL_RGBA32F; glFormat = GL_RGBA; glType = GL_FLOAT;
            break;
        case OpenGLFormat::Depth24Stencil8:
            internalFormat = GL_DEPTH24_STENCIL8; glFormat = GL_DEPTH_STENCIL; glType = GL_UNSIGNED_INT_24_8;
            break;
        case OpenGLFormat::Depth32F:
            internalFormat = GL_DEPTH_COMPONENT32F; glFormat = GL_DEPTH_COMPONENT; glType = GL_FLOAT;
            break;
        default:
            internalFormat = GL_RGBA8; glFormat = GL_RGBA; glType = GL_UNSIGNED_BYTE;
            break;
    }
}

OpenGLTexture::OpenGLTexture()
    : m_texture(0)
    , m_type(OpenGLTextureType::Texture2D)
    , m_width(0)
    , m_height(0)
    , m_depth(0)
    , m_mipLevels(1)
    , m_channels(0) {
}

OpenGLTexture::~OpenGLTexture() {
    Shutdown();
}

bool OpenGLTexture::Initialize(OpenGLTextureType type, int width, int height, int depth, int mipLevels, OpenGLFormat format, const void* data) {
    m_type = type;
    m_width = width;
    m_height = height;
    m_depth = depth;
    m_mipLevels = mipLevels;

    unsigned int target = ToGLTextureTarget(type);
    unsigned int internalFormat, glFormat, glType;
    ToGLFormat(format, internalFormat, glFormat, glType);

    glGenTextures(1, &m_texture);
    glBindTexture(target, m_texture);

    if (type == OpenGLTextureType::TextureCube) {
        for (int i = 0; i < 6; i++) {
            glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, internalFormat, width, height, 0, glFormat, glType, data);
        }
    } else if (type == OpenGLTextureType::Texture1D) {
        glTexImage1D(GL_TEXTURE_1D, 0, internalFormat, width, 0, glFormat, glType, data);
    } else if (type == OpenGLTextureType::Texture3D) {
        glTexImage3D(GL_TEXTURE_3D, 0, internalFormat, width, height, depth, 0, glFormat, glType, data);
    } else {
        glTexImage2D(target, 0, internalFormat, width, height, 0, glFormat, glType, data);
    }

    if (mipLevels > 1) {
        glTexParameteri(target, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    } else {
        glTexParameteri(target, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    }
    glTexParameteri(target, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(target, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(target, GL_TEXTURE_WRAP_T, GL_REPEAT);

    glBindTexture(target, 0);
    return true;
}

bool OpenGLTexture::Initialize2D(int width, int height, int channels, const void* data, bool generateMipmap) {
    m_channels = channels;
    m_type = OpenGLTextureType::Texture2D;
    m_width = width;
    m_height = height;
    m_depth = 1;
    m_mipLevels = generateMipmap ? 0 : 1;

    glGenTextures(1, &m_texture);
    glBindTexture(GL_TEXTURE_2D, m_texture);

    GLenum format = (channels == 4) ? GL_RGBA : GL_RGB;
    glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);

    if (generateMipmap) {
        glGenerateMipmap(GL_TEXTURE_2D);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    } else {
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    }

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

    glBindTexture(GL_TEXTURE_2D, 0);
    return true;
}

bool OpenGLTexture::InitializeCubeMap(int size, int mipLevels, OpenGLFormat format, const void* data) {
    m_type = OpenGLTextureType::TextureCube;
    m_width = size;
    m_height = size;
    m_depth = 1;
    m_mipLevels = mipLevels;

    unsigned int internalFormat, glFormat, glType;
    ToGLFormat(format, internalFormat, glFormat, glType);

    glGenTextures(1, &m_texture);
    glBindTexture(GL_TEXTURE_CUBE_MAP, m_texture);

    for (int i = 0; i < 6; i++) {
        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, internalFormat, size, size, 0, glFormat, glType, data);
    }

    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, mipLevels > 1 ? GL_LINEAR_MIPMAP_LINEAR : GL_LINEAR);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);

    glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
    return true;
}

bool OpenGLTexture::LoadFromFile(const char* path, bool flipVertical) {
    stbi_set_flip_vertically_on_load(flipVertical ? 1 : 0);

    unsigned char* data = stbi_load(path, &m_width, &m_height, &m_channels, 0);
    if (!data) {
        std::cout << "Failed to load texture: " << path << std::endl;
        return false;
    }

    bool result = Initialize2D(m_width, m_height, m_channels, data, true);
    stbi_image_free(data);
    return result;
}

void OpenGLTexture::Shutdown() {
    if (m_texture) {
        glDeleteTextures(1, &m_texture);
        m_texture = 0;
    }
}

void OpenGLTexture::Bind(int slot) const {
    unsigned int target = ToGLTextureTarget(m_type);
    glActiveTexture(GL_TEXTURE0 + slot);
    glBindTexture(target, m_texture);
}

void OpenGLTexture::Unbind() const {
    unsigned int target = ToGLTextureTarget(m_type);
    glBindTexture(target, 0);
}

void OpenGLTexture::BindImage(int slot, bool read, bool write) const {
    unsigned int target = ToGLTextureTarget(m_type);
    GLenum access = (read && write) ? GL_READ_WRITE : (read ? GL_READ_ONLY : GL_WRITE_ONLY);
    glBindImageTexture(slot, m_texture, 0, GL_FALSE, 0, access, GL_RGBA8);
}

void OpenGLTexture::GenerateMipmap() {
    unsigned int target = ToGLTextureTarget(m_type);
    glBindTexture(target, m_texture);
    glGenerateMipmap(target);
    glBindTexture(target, 0);
}

void OpenGLTexture::SetFiltering(int minFilter, int magFilter) {
    unsigned int target = ToGLTextureTarget(m_type);
    glBindTexture(target, m_texture);
    glTexParameteri(target, GL_TEXTURE_MIN_FILTER, minFilter);
    glTexParameteri(target, GL_TEXTURE_MAG_FILTER, magFilter);
    glBindTexture(target, 0);
}

void OpenGLTexture::SetWrapping(int wrapS, int wrapT, int wrapR) {
    unsigned int target = ToGLTextureTarget(m_type);
    glBindTexture(target, m_texture);
    glTexParameteri(target, GL_TEXTURE_WRAP_S, wrapS);
    glTexParameteri(target, GL_TEXTURE_WRAP_T, wrapT);
    if (wrapR >= 0 && (m_type == OpenGLTextureType::Texture3D || m_type == OpenGLTextureType::TextureCube)) {
        glTexParameteri(target, GL_TEXTURE_WRAP_R, wrapR);
    }
    glBindTexture(target, 0);
}

} // namespace RHI
} // namespace XCEngine