// StgSharpGraphics.c : 定义 DLL 的导出函数。
//

#include "StgSharpGraphics.h"
#include "glad/glad.h"
#include "GLFW/glfw3.h"
#include "framework.h"
#include "stdio.h"
#include "internal.h"

extern float* triangleVertexes;
double previousTime = 0;
double targetFPS = 60.0;

const char* vertexShaderSource =
"#version 460 core\n"
"layout (location = 0) in vec3 aPos;\n"
"void main()\n"
"{\n"
"gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
"}\n\0";

const char* fragmentShaderSource =
"#version 460 core\n"
"out vec4 FragColor;\n"
"void main()\n"
"{\n"
"FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
"}\n\0"
;

float triangle[] =
{
    0,0.5f,0,
    -0.5f,-0.5f,0,
    0.5f,-0.5f,0,
};

int version[4] = { 0,0,0,0 };
STGSHARPGRAPHICS_API int* versionInfo = &version;


// 这是导出函数的一个示例。


STGSHARPGRAPHICS_API IOpackage initPackage(void)
{
    IOpackage pack;
    pack.InitWindow = InitWindow;
    return pack;
}

STGSHARPGRAPHICS_API basicWindowInfo* InitWindow(basicWindowInfo info)
{

    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

#ifdef __APPLE__
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif // __APPLE__

    GLFWwindow* window = glfwCreateWindow(info.width, info.height, info.name, NULL, NULL);
    if (window == NULL)
    {
        printf("Failed to create GLFW window");
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);

    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        printf("Failed to initialize GLAD");
        return -1;
    }

    glfwSwapInterval(0);
    return window;
}

STGSHARPGRAPHICS_API void ComppileShader(void)
{
    //编译顶点着色器

    unsigned int vertexShader;
    vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    glCompileShader(vertexShader);

    //编译片段着色器

    unsigned int fragmentShader;
    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
    glCompileShader(fragmentShader);

    //创建着色器程序

    unsigned int shaderProgram;
    shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glUseProgram(shaderProgram);
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);

    // 链接顶点属性

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);


    //创建顶点缓存实例

    unsigned int VBO;
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 3 * 3, triangle, GL_STATIC_DRAW);

    //创建顶点数组实例

    unsigned int VAO;
    glGenVertexArrays(1, &VAO);
    glBindVertexArray(VAO);
    // 2. 把顶点数组复制到缓冲中供OpenGL使用
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 3 * 3, triangle, GL_STATIC_DRAW);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);

    /**/
}

STGSHARPGRAPHICS_API void RenderWindow(GLFWwindow* window, basicWindowInfo info)
{
    while (!glfwWindowShouldClose(window))
    {
        if (1)
        {

        }
        // input
        // -----

        // render
        // ------

        /**/
        glClearColor(
            info.backgroundColor.x,
            info.backgroundColor.y,
            info.backgroundColor.Z,
            info.backgroundColor.w
        );
        /**/
        //glClearColor(0.1f,0.3f,0.5f,1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        // draw our first triangle
        /*
        glUseProgram(shaderProgram);
        glBindVertexArray(VAO);
        // seeing as we only have a single VAO there's no need to bind it every time, 
        // but we'll do so to keep things a bit more organized
        glDrawArrays(GL_TRIANGLES, 0, 3);
        //glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        // glBindVertexArray(0); // no need to unbind it every time
        /**/
        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
        // -------------------------------------------------------------------------------
        glfwSwapBuffers(window);
        glfwPollEvents();
    }
}

STGSHARPGRAPHICS_API void TerminateWindow(void)
{
    // glfw: terminate, clearing all previously allocated GLFW resources.
    // ------------------------------------------------------------------
    glfwTerminate();

    /*
    //glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    //glDeleteBuffers(1, &EBO);
    glDeleteProgram(shaderProgram);
    /**/
}