/*     put these  on vShader.vs &  fShader.fs
________________________________________________________________
vShader.vs :
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;

uniform float xPos;
uniform float yPos;
out vec3 ourColor;

void main()
{

    gl_Position = vec4(aPos.x + xPos,aPos.y + yPos,aPos.z, 1.0);
    ourColor = aColor;
}
________________________________________________________________
fShader.fs :
#version 330 core
out vec4 FragColor;

in vec3 ourColor;

void main()
{
    FragColor = vec4(ourColor, 1.0f);
}
________________________________________________________________
*/
#include <iostream>
#include <glad\glad.h>
#include <GLFW\glfw3.h>
#include <GLFW\shader_s.h>
bool pressedOnce = false;
float xOffset = 0.0f;
float yOffset = 0.0f;
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
	if (glfwGetKey(window, GLFW_KEY_ENTER) == GLFW_PRESS)
		pressedOnce = true;
	if (glfwGetKey(window, GLFW_KEY_ENTER) == GLFW_RELEASE && pressedOnce == true)
		glfwSetWindowShouldClose(window, true);
	if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
		yOffset += 5;
	if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
		yOffset -= 5;
	if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
		xOffset += 5;
	if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
		xOffset -= 5;
}
void GLAD_Check()
{
	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
		std::cout << "Failed to initialize GLAD" << std::endl;
}
void Resizer(GLFWwindow *window, int width , int height)
{
	glViewport(0, 0, width, height);
}

int main()
{
	// Setup ------------------------------------
	// window*********
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
	GLFWwindow *window = glfwCreateWindow(800, 600, "Shaders", NULL, NULL);
	glfwMakeContextCurrent(window);
	GLAD_Check();
	glViewport(0, 0, 800, 600);
	glfwSetFramebufferSizeCallback(window, Resizer);

	float vertcies[] =
	{     // vertcies			// color
		0.0f, 0.5f, 1.0f,    1.0f, 0.0f, 0.0f,  // top middle
		- 0.5f, -0.5f, 1.0f, 0.0f, 1.0f, 0.0f,// bot left
		0.5f, -0.5f, 1.0f,   0.0f, 0.0f, 1.0f//  bot right
	};

	// VBO & VAO ********
	unsigned int VBO;
	glGenBuffers(1, &VBO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertcies), vertcies,GL_STATIC_DRAW);
	glCompileShader(VBO);

	unsigned int VAO;
	glGenVertexArrays(1, &VAO);
	glBindVertexArray(VAO);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
	glEnableVertexAttribArray(1);
	Shader programShader("Shaders/vShader.vs", "Shaders/fShader.fs"); // fragment/vertex shader Path

	while (!glfwWindowShouldClose(window))
	{
		glfwSetKeyCallback(window, key_callback);
		glClear(GL_COLOR_BUFFER_BIT);
		glClearColor(0.1f, 0.3f, 0.6f,1.0f);
		programShader.use();
		glUniform1f(glGetUniformLocation(programShader.ID, "xPos"), xOffset / 800);
		glUniform1f(glGetUniformLocation(programShader.ID, "yPos"), yOffset / 600);
		glBindVertexArray(VAO);
		glDrawArrays(GL_TRIANGLES,0,3);
		glfwPollEvents();
		glfwSwapBuffers(window);
	}
	glfwTerminate();
	return 0;
}