OpenGLFrameBuffer.cpp

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#include "eepch.h"
#include "OpenGLFrameBuffer.h"
 
#include <ElevateEngine/Core/Assert.h>
#include <ElevateEngine/Renderer/Renderer.h>
#include <ElevateEngine/Renderer/GLDebug.h>
#include <ElevateEngine/Renderer/GraphicsAPI.h>
 
// TODO : ADD GLCHECK TO EACH LINES
 
Elevate::OpenGLFrameBuffer::OpenGLFrameBuffer(TexturePtr tex) : Framebuffer(tex)
{
    EE_CORE_ASSERT(tex->GetWidth() > 0 && tex->GetHeight() > 0, "Framebuffer dimensions must be positive");
 
    // Creating and binding
    glGenFramebuffers(1, &m_frameBufferId);
    Bind();
 
    m_textureId = static_cast<GLuint>(reinterpret_cast<intptr_t>(tex->GetNativeHandle()));
 
    // Bind the texture with the Frame Buffer
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_textureId, 0);
    // render buffer
    glGenRenderbuffers(1, &m_renderBufferId);
    glBindRenderbuffer(GL_RENDERBUFFER, m_renderBufferId);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, tex->GetWidth(), tex->GetHeight());
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, m_renderBufferId);
    
    CheckCompleteness();
    Unbind();
}
 
void Elevate::OpenGLFrameBuffer::Bind() const
{
    glBindFramebuffer(GL_FRAMEBUFFER, m_frameBufferId);
}
 
void Elevate::OpenGLFrameBuffer::Unbind() const
{
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
}
 
void Elevate::OpenGLFrameBuffer::BlitFramebufferToScreen(uint32_t screenWidth, uint32_t screenHeight) const
{
    GLCheck(glBindFramebuffer(GL_READ_FRAMEBUFFER, m_frameBufferId)); // Read from this framebuffer
    GLCheck(glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0)); // Draw to the main framebuffer
 
    // TODO GIVE A CHOICE TO THE USER FOR THE FILTERING
    glBlitFramebuffer(
        0, 0, m_texture->GetWidth(), m_texture->GetHeight(),
        0, 0, screenWidth, screenHeight,
        GL_COLOR_BUFFER_BIT, GL_NEAREST
    );
}
 
void Elevate::OpenGLFrameBuffer::Rescale(uint32_t width, uint32_t height)
{
    if (width == m_texture->GetWidth() && height == m_texture->GetHeight()) return;
    else if (width <= 0 || height <= 0) return;
 
    Bind();
 
    Renderer::BindTexture(m_texture);
 
    TextureMetadata meta = m_texture->GetMetadata();
    meta.Width = width;
    meta.Height = height;
 
    m_texture->SetData(nullptr, meta);
 
    // Attacher la texture redimensionn�e au framebuffer
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_textureId, 0);
 
    // Redimensionner le renderbuffer pour le depth/stencil
    glBindRenderbuffer(GL_RENDERBUFFER, m_renderBufferId);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
    glBindRenderbuffer(GL_RENDERBUFFER, 0); // Unbind renderbuffer
 
    CheckCompleteness();
    Unbind();
}
 
bool Elevate::OpenGLFrameBuffer::CheckCompleteness() const
{
    uint32_t status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
    if (status != GL_FRAMEBUFFER_COMPLETE) {
        const char* msg = GetFramebufferStatusString(status);
        EE_CORE_ERROR("Framebuffer error: {}", msg);
        return false;
    }
    return true;
}
 
const char* Elevate::OpenGLFrameBuffer::GetFramebufferStatusString(uint32_t status) const
{
    switch (status) 
    {
        case GL_FRAMEBUFFER_COMPLETE: return "COMPLETE";
        case GL_FRAMEBUFFER_UNDEFINED: return "UNDEFINED";
        case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT: return "INCOMPLETE_ATTACHMENT";
        case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT: return "MISSING_ATTACHMENT";
        case GL_FRAMEBUFFER_UNSUPPORTED: return "UNSUPPORTED_FORMAT";
        case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE: return "INCOMPLETE_MULTISAMPLE";
        default: return "UNKNOWN_ERROR";
    }
}