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

#define GLFW_INCLUDE_NONE
#include "XCEngine/RHI/OpenGL/OpenGLSampler.h"
#include <glad/glad.h>
#include <GLFW/glfw3.h>

namespace XCEngine {
namespace RHI {

static unsigned int ToGLWrapMode(SamplerWrapMode mode) {
    switch (mode) {
        case SamplerWrapMode::Repeat: return GL_REPEAT;
        case SamplerWrapMode::MirroredRepeat: return GL_MIRRORED_REPEAT;
        case SamplerWrapMode::ClampToEdge: return GL_CLAMP_TO_EDGE;
        case SamplerWrapMode::ClampToBorder: return GL_CLAMP_TO_BORDER;
        default: return GL_REPEAT;
    }
}

static unsigned int ToGLFilter(SamplerFilter filter) {
    switch (filter) {
        case SamplerFilter::Nearest: return GL_NEAREST;
        case SamplerFilter::Linear: return GL_LINEAR;
        case SamplerFilter::NearestMipmapNearest: return GL_NEAREST_MIPMAP_NEAREST;
        case SamplerFilter::LinearMipmapNearest: return GL_LINEAR_MIPMAP_NEAREST;
        case SamplerFilter::NearestMipmapLinear: return GL_NEAREST_MIPMAP_LINEAR;
        case SamplerFilter::LinearMipmapLinear: return GL_LINEAR_MIPMAP_LINEAR;
        default: return GL_LINEAR;
    }
}

OpenGLSampler::OpenGLSampler() : m_sampler(0) {
}

OpenGLSampler::~OpenGLSampler() {
}

bool OpenGLSampler::Initialize(const OpenGLSamplerDesc& desc) {
    m_desc = desc;
    glGenSamplers(1, &m_sampler);
    
    glSamplerParameteri(m_sampler, GL_TEXTURE_MIN_FILTER, ToGLFilter(desc.minFilter));
    glSamplerParameteri(m_sampler, GL_TEXTURE_MAG_FILTER, ToGLFilter(desc.magFilter));
    glSamplerParameteri(m_sampler, GL_TEXTURE_WRAP_S, ToGLWrapMode(desc.wrapS));
    glSamplerParameteri(m_sampler, GL_TEXTURE_WRAP_T, ToGLWrapMode(desc.wrapT));
    glSamplerParameteri(m_sampler, GL_TEXTURE_WRAP_R, ToGLWrapMode(desc.wrapR));
    glSamplerParameterf(m_sampler, GL_TEXTURE_MIN_LOD, desc.minLod);
    glSamplerParameterf(m_sampler, GL_TEXTURE_MAX_LOD, desc.maxLod);
    glSamplerParameterf(m_sampler, GL_TEXTURE_MAX_ANISOTROPY, desc.maxAnisotropy);
    
    return true;
}

void OpenGLSampler::Shutdown() {
    if (m_sampler) {
        glDeleteSamplers(1, &m_sampler);
        m_sampler = 0;
    }
}

void OpenGLSampler::Bind(unsigned int unit) {
    glBindSampler(unit, m_sampler);
}

void OpenGLSampler::Unbind(unsigned int unit) {
    glBindSampler(unit, 0);
}

} // namespace RHI
} // namespace XCEngine