// 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;


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";

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"
;

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 int fnStgSharpGraphics(void)
{
    return 0;
}

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

STGSHARPGRAPHICS_API int initWindow(int width, int height)
{

    //编译顶点着色器

    unsigned int vertexShader;
    vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader,1,&vertexShaderSource,NULL);
    glCompileShader(vertexShader);
    int  success;
    char infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
        printf("\i",infoLog);
    }

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

   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(width, height, "LearnOpenGL", 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;
   }

   while (!glfwWindowShouldClose(window))
   {
      // input
      // -----

      // render
      // ------
      glClearColor(0.2f, 0.3f, 0.3f, 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, 6);
      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();
   }

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

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

   return 0;
}


void renderTriangle()
{

}