#include "PlayerGLWidget.h"


PlayerGLWidget::PlayerGLWidget(QWidget *parent) : QOpenGLWidget(parent)
{

}

PlayerGLWidget::~PlayerGLWidget()
{

}

/* 刷新一帧 */
void PlayerGLWidget::updateFrame(Image_YUV420& image)
{
    yData = image.yData;
    uData = image.uData;
    vData = image.vData;
    update();
}


void PlayerGLWidget::initShaders()
{
    // 顶点着色器
    const char *vshader = R"(
        #version 330 core
        layout(location = 0) in vec4 vertexIn;
        layout(location = 1) in vec2 textureIn;
        out vec2 textureOut;
        void main(void)
        {
            gl_Position = vertexIn;
            textureOut = textureIn;
        })";
    // 片段着色器（YUV420P 转 RGB）
    const char *fshader = R"(
        #version 330 core
        in vec2 textureOut;
        out vec4 fragColor;
        uniform sampler2D tex_y;
        uniform sampler2D tex_u;
        uniform sampler2D tex_v;
        void main(void)
        {
            float y = texture(tex_y, textureOut).r;
            float u = texture(tex_u, textureOut).r - 0.5;
            float v = texture(tex_v, textureOut).r - 0.5;
            float r = y + 1.403 * v;
            float g = y - 0.344 * u - 0.714 * v;
            float b = y + 1.770 * u;
            fragColor = vec4(r, g, b, 1.0);
        })";
    // 创建着色器程序
    program.addShaderFromSourceCode(QOpenGLShader::Vertex, vshader);
    program.addShaderFromSourceCode(QOpenGLShader::Fragment, fshader);
    program.link();
}

void PlayerGLWidget::initTextures()
{
    // 创建 YUV 纹理
        textureY = new QOpenGLTexture(QOpenGLTexture::Target2D);
        textureU = new QOpenGLTexture(QOpenGLTexture::Target2D);
        textureV = new QOpenGLTexture(QOpenGLTexture::Target2D);

        textureY->create();
        textureU->create();
        textureV->create();
}

// void PlayerGLWidget::initVertex()
// {

// }

// void PlayerGLWidget::initFrameBuffer()
// {

// }

void PlayerGLWidget::renderYUV420P()
{
    if (yData.isEmpty() || uData.isEmpty() || vData.isEmpty())
            return;

        // 绑定纹理
        textureY->bind(0);
        textureU->bind(1);
        textureV->bind(2);

        // 上传 YUV 数据到纹理
        textureY->setData(QOpenGLTexture::Red, QOpenGLTexture::UInt8, yData.constData());
        textureU->setData(QOpenGLTexture::Red, QOpenGLTexture::UInt8, uData.constData());
        textureV->setData(QOpenGLTexture::Red, QOpenGLTexture::UInt8, vData.constData());

        // 绑定着色器程序
        program.bind();
        program.setUniformValue("tex_y", 0);
        program.setUniformValue("tex_u", 1);
        program.setUniformValue("tex_v", 2);

        // 绘制矩形
        static const GLfloat vertices[] = {
            -1.0f, -1.0f, 0.0f,
             1.0f, -1.0f, 0.0f,
            -1.0f,  1.0f, 0.0f,
             1.0f,  1.0f, 0.0f
        };

        static const GLfloat texCoords[] = {
            0.0f, 1.0f,
            1.0f, 1.0f,
            0.0f, 0.0f,
            1.0f, 0.0f
        };

        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, vertices);
        glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, texCoords);
        glEnableVertexAttribArray(0);
        glEnableVertexAttribArray(1);

        glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

        program.release();
}

void PlayerGLWidget::initializeGL()
{
    initializeOpenGLFunctions();
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    // 初始化着色器
    initShaders();
    initTextures();
}

void PlayerGLWidget::resizeGL(int w, int h)
{
    glViewport(0, 0, w, h);
}

void PlayerGLWidget::paintGL()
{
    glClear(GL_COLOR_BUFFER_BIT);

    // 渲染 YUV 数据
    renderYUV420P();
}