#include "Canvas.h"
#include "EngineCore/Game.h"
#include "EngineFrame/Render/RenderManager.h"
Canvas::Canvas()
{
    
}
Canvas::Canvas(VecSize size)
{
    Init(size);
}

Canvas::Canvas(int width, int height)
{
    Init({width, height});
}

void Canvas::Init(VecSize size)
{
    m_size = size;
    SetSize(size);
    // 创建指定大小的纹理
    m_texture = new Texture();
    m_texture->Init(m_size);

    // 构造FBO
    glGenFramebuffers(1, &m_fbo);
    glBindFramebuffer(GL_FRAMEBUFFER, m_fbo);
    // 将目标纹理附加到FBO的颜色附着点
    glFramebufferTexture2D(
        GL_FRAMEBUFFER,       // 帧缓冲类型
        GL_COLOR_ATTACHMENT0, // 颜色附着点（可多个，这里用第一个）
        GL_TEXTURE_2D,        // 纹理类型
        m_texture->getID(),   // 目标纹理ID
        0                     // 多级渐远纹理级别
    );
    glBindFramebuffer(GL_FRAMEBUFFER, 0); // 解绑FBO
}

void Canvas::BeginDraw()
{
    RenderManager *renderer = Game::GetInstance().GetRenderer();
    // 绑定FBO
    glBindFramebuffer(GL_FRAMEBUFFER, m_fbo);
    // 清屏
    glClear(GL_COLOR_BUFFER_BIT);
    // 保存原始的正交矩阵 设置纹理对应的正交矩阵 和 视口
    Oom = renderer->GetOrthoMatrix();
    renderer->SetOrthoMatrix(glm::ortho(0.0f, (float)m_size.width, 0.0f, (float)m_size.height, -1.0f, 1.0f));
    Oviewport = renderer->GetViewport();
    renderer->SetViewport({0, 0, m_size.width, m_size.height});

}

void Canvas::EndDraw()
{
    RenderManager *renderer = Game::GetInstance().GetRenderer();
    // 解绑FBO
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    // 恢复原始的正交矩阵 和 视口
    renderer->SetOrthoMatrix(Oom);
    renderer->SetViewport(Oviewport);
}

void Canvas::DrawActor(RefPtr<Actor> actor)
{
    // 计算矩阵
    actor->PreRender();
    // 设定矩阵并渲染(Render中会调用OnRender)
    actor->Render();
}

void Canvas::Clear()
{
    m_texture = new Texture();
    m_texture->Init(m_size);
}

void Canvas::OnRender()
{
    if (!m_texture || !IsVisible())
        return;

    RenderManager *renderer = Game::GetInstance().GetRenderer();
    if (this->_BlendMode != NONE)
    {
        renderer->SetBlendMode(this->_BlendMode);
    }
    renderer->DrawTexture(m_texture);
    if (this->_BlendMode != NONE)
    {
        renderer->SetBlendMode(NONE);
    }
}

// void Canvas::Render()
// {
// RenderManager *renderer = Game::GetInstance().GetRenderer();
// SDL_FPoint AnchorPos = {0, 0};
// if (m_dirty)
// {
//     glBindFramebuffer(GL_FRAMEBUFFER, m_fbo); // 绑定FBO
//     glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
//     glClear(GL_COLOR_BUFFER_BIT);
//     for (auto &info : m_drawQueue)
//     {
//         renderer->DrawTexture(m_imgMap[info.texture], nullptr, &info.rect, 0.f, &AnchorPos, SDL_FLIP_NONE);
//     }
//     glBindFramebuffer(GL_FRAMEBUFFER, 0); // 解绑FBO
//     m_dirty = false;
// }

// renderer->SetCurrentShaderProgram("flip_y");
// // 混合
// if (this->_BlendMode != NONE)
//     Blend();
// renderer->DrawTexture(m_texture, &m_renderRect, &m_rect, 0.f, &AnchorPos, SDL_FLIP_NONE);
// // 还原混合
// if (this->_BlendMode != NONE)
//     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
// renderer->SetCurrentShaderProgram("normal");
// }