opengl 라이팅 Phong모델

 

// sb6.h 헤더 파일을 포함시킨다.
#include <sb7.h>
#include <vmath.h>
#include <shader.h>

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"

// sb6::application을 상속받는다.
class my_application : public sb7::application
{
public:
	// 쉐이더 컴파일한다.


	// basic lighting shader
	GLuint compile_shader2(void)
	{
		// 버텍스 쉐이더를 생성하고 컴파일한다.
		GLuint vertex_shader = sb7::shader::load("basic_lighting_vs.glsl", GL_VERTEX_SHADER);

		// 프래그먼트 쉐이더를 생성하고 컴파일한다.
		GLuint fragment_shader = sb7::shader::load("basic_lighting_fs.glsl", GL_FRAGMENT_SHADER);

		// 프로그램을 생성하고 쉐이더를 Attach시키고 링크한다.
		GLuint program = glCreateProgram();
		glAttachShader(program, vertex_shader);
		glAttachShader(program, fragment_shader);
		glLinkProgram(program);

		// 이제 프로그램이 쉐이더를 소유하므로 쉐이더를 삭제한다.
		glDeleteShader(vertex_shader);
		glDeleteShader(fragment_shader);

		return program;
	}

	// simple color shader
	GLuint compile_shader3(void)
	{
		// 버텍스 쉐이더를 생성하고 컴파일한다.
		GLuint vertex_shader = sb7::shader::load("simple_color_vs.glsl", GL_VERTEX_SHADER);

		// 프래그먼트 쉐이더를 생성하고 컴파일한다.
		GLuint fragment_shader = sb7::shader::load("simple_color_fs.glsl", GL_FRAGMENT_SHADER);

		// 프로그램을 생성하고 쉐이더를 Attach시키고 링크한다.
		GLuint program = glCreateProgram();
		glAttachShader(program, vertex_shader);
		glAttachShader(program, fragment_shader);
		glLinkProgram(program);

		// 이제 프로그램이 쉐이더를 소유하므로 쉐이더를 삭제한다.
		glDeleteShader(vertex_shader);
		glDeleteShader(fragment_shader);

		return program;
	}

	// 애플리케이션 초기화 수행한다.
	virtual void startup()
	{
		// 쉐이더 프로그램 컴파일 및 연결
		shader_programs[1] = compile_shader2();
		shader_programs[2] = compile_shader3();

		// VAO, VBO, EBO, texture 생성
		glGenVertexArrays(3, VAOs);
		glGenBuffers(3, VBOs);
		glGenBuffers(2, EBOs);
		glGenTextures(3, textures);

		stbi_set_flip_vertically_on_load(true);

		
		// 두 번째 객체 정의 : 박스 --------------------------------------------------
		glBindVertexArray(VAOs[1]);
		// 박스 점들의 위치와 컬러, 텍스처 좌표를 정의한다.
		float box_s = 1.0f, box_t = 1.0f;
		GLfloat box_vertices[] = {
			// 뒷면
			-0.25f, 0.5f, -0.25f, 1.0f, 0.0f, 0.0f,		box_s, box_t,	0.0f, 0.0f, -1.0f,
			0.25f, 0.0f, -0.25f, 1.0f, 0.0f, 0.0f,		0.0f, 0.0f,		0.0f, 0.0f, -1.0f,
			-0.25f, 0.0f, -0.25f, 1.0f, 0.0f, 0.0f,		box_s, 0.0f,	0.0f, 0.0f, -1.0f,

			0.25f, 0.0f, -0.25f, 1.0f, 0.0f, 0.0f,		0.0f, 0.0f,		0.0f, 0.0f, -1.0f,
			-0.25f, 0.5f, -0.25f, 1.0f, 0.0f, 0.0f,		box_s, box_t,	0.0f, 0.0f, -1.0f,
			0.25f, 0.5f, -0.25f, 1.0f, 0.0f, 0.0f,		0.0f, box_t,	0.0f, 0.0f, -1.0f,
			// 우측면
			0.25f, 0.0f, -0.25f, 0.0f, 1.0f, 0.0f,		box_s, 0.0f,	1.0f, 0.0f, 0.0f,
			0.25f, 0.5f, -0.25f, 0.0f, 1.0f, 0.0f,		box_s, box_t,	1.0f, 0.0f, 0.0f,
			0.25f, 0.0f, 0.25f, 0.0f, 1.0f, 0.0f,		0.0f, 0.0f,		1.0f, 0.0f, 0.0f,

			0.25f, 0.0f, 0.25f, 0.0f, 1.0f, 0.0f,		0.0f, 0.0f,		1.0f, 0.0f, 0.0f,
			0.25f, 0.5f, -0.25f, 0.0f, 1.0f, 0.0f,		box_s, box_t,	1.0f, 0.0f, 0.0f,
			0.25f, 0.5f, 0.25f, 0.0f, 1.0f, 0.0f,		0.0f, box_t,	1.0f, 0.0f, 0.0f,
			// 정면
			0.25f, 0.0f, 0.25f, 0.0f, 0.0f, 1.0f,		box_s, 0.0f,	0.0f, 0.0f, 1.0f,
			0.25f, 0.5f, 0.25f, 0.0f, 0.0f, 1.0f,		box_s, box_t,	0.0f, 0.0f, 1.0f,
			-0.25f, 0.0f, 0.25f, 0.0f, 0.0f, 1.0f,		0.0f, 0.0f,		0.0f, 0.0f, 1.0f,

			-0.25f, 0.0f, 0.25f, 0.0f, 0.0f, 1.0f,		0.0f, 0.0f,		0.0f, 0.0f, 1.0f,
			0.25f, 0.5f, 0.25f, 0.0f, 0.0f, 1.0f,		box_s, box_t,	0.0f, 0.0f, 1.0f,
			-0.25f, 0.5f, 0.25f, 0.0f, 0.0f, 1.0f,		0.0f, box_t,	0.0f, 0.0f, 1.0f,
			// 좌측면
			-0.25f, 0.0f, 0.25f, 1.0f, 0.0f, 1.0f,		box_s, 0.0f,	-1.0f, 0.0f, 0.0f,
			-0.25f, 0.5f, 0.25f, 1.0f, 0.0f, 1.0f,		box_s, box_t,	-1.0f, 0.0f, 0.0f,
			-0.25f, 0.0f, -0.25f, 1.0f, 0.0f, 1.0f,		0.0f, 0.0f,		-1.0f, 0.0f, 0.0f,

			-0.25f, 0.0f, -0.25f, 1.0f, 0.0f, 1.0f,		0.0f, 0.0f,		-1.0f, 0.0f, 0.0f,
			-0.25f, 0.5f, 0.25f, 1.0f, 0.0f, 1.0f,		box_s, box_t,	-1.0f, 0.0f, 0.0f,
			-0.25f, 0.5f, -0.25f, 1.0f, 0.0f, 1.0f,		0.0f, box_t,	-1.0f, 0.0f, 0.0f,
			// 바닥면
			-0.25f, 0.0f, 0.25f, 1.0f, 1.0f, 0.0f,		box_s, 0.0f,	0.0f, -1.0f, 0.0f,
			0.25f, 0.0f, -0.25f, 1.0f, 1.0f, 0.0f,		0.0f, box_t,	0.0f, -1.0f, 0.0f,
			0.25f, 0.0f, 0.25f, 1.0f, 1.0f, 0.0f,		0.0f, 0.0f,		0.0f, -1.0f, 0.0f,

			0.25f, 0.0f, -0.25f, 1.0f, 1.0f, 0.0f,		0.0f, box_t,	0.0f, -1.0f, 0.0f,
			-0.25f, 0.0f, 0.25f, 1.0f, 1.0f, 0.0f,		box_s, 0.0,		0.0f, -1.0f, 0.0f,
			-0.25f, 0.0f, -0.25f, 1.0f, 1.0f, 0.0f,		box_s, box_t,	0.0f, -1.0f, 0.0f,
			// 윗면
			-0.25f, 0.5f, -0.25f, 0.0f, 1.0f, 1.0f,		0.0f, box_t,	0.0f, 1.0f, 0.0f,
			0.25f, 0.5f, 0.25f, 0.0f, 1.0f, 1.0f,		box_s, 0.0f,	0.0f, 1.0f, 0.0f,
			0.25f, 0.5f, -0.25f, 0.0f, 1.0f, 1.0f,		box_s, box_t,	0.0f, 1.0f, 0.0f,

			0.25f, 0.5f, 0.25f, 0.0f, 1.0f, 1.0f,		box_s, 0.0f,	0.0f, 1.0f, 0.0f,
			-0.25f, 0.5f, -0.25f, 0.0f, 1.0f, 1.0f,		0.0f, box_t,	0.0f, 1.0f, 0.0f,
			-0.25f, 0.5f, 0.25f, 0.0f, 1.0f, 1.0f,		0.0f, 0.0f,		0.0f, 1.0f, 0.0f,

			//=================================================================================
			1.75f, 0.5f, -0.25f, 1.0f, 0.0f, 0.0f,		box_s, box_t,	0.0f, 0.0f, -1.0f,
			2.25f, 0.0f, -0.25f, 1.0f, 0.0f, 0.0f,		0.0f, 0.0f,		0.0f, 0.0f, -1.0f,
			1.75f, 0.0f, -0.25f, 1.0f, 0.0f, 0.0f,		box_s, 0.0f,	0.0f, 0.0f, -1.0f,

			2.25f, 0.0f, -0.25f, 1.0f, 0.0f, 0.0f,		0.0f, 0.0f,		0.0f, 0.0f, -1.0f,
			1.75f, 0.5f, -0.25f, 1.0f, 0.0f, 0.0f,		box_s, box_t,	0.0f, 0.0f, -1.0f,
			2.25f, 0.5f, -0.25f, 1.0f, 0.0f, 0.0f,		0.0f, box_t,	0.0f, 0.0f, -1.0f,
			// 우측면
			2.25f, 0.0f, -0.25f, 0.0f, 1.0f, 0.0f,		box_s, 0.0f,	1.0f, 0.0f, 0.0f,
			2.25f, 0.5f, -0.25f, 0.0f, 1.0f, 0.0f,		box_s, box_t,	1.0f, 0.0f, 0.0f,
			2.25f, 0.0f, 0.25f, 0.0f, 1.0f, 0.0f,		0.0f, 0.0f,		1.0f, 0.0f, 0.0f,

			2.25f, 0.0f, 0.25f, 0.0f, 1.0f, 0.0f,		0.0f, 0.0f,		1.0f, 0.0f, 0.0f,
			2.25f, 0.5f, -0.25f, 0.0f, 1.0f, 0.0f,		box_s, box_t,	1.0f, 0.0f, 0.0f,
			2.25f, 0.5f, 0.25f, 0.0f, 1.0f, 0.0f,		0.0f, box_t,	1.0f, 0.0f, 0.0f,
			// 정면
			2.25f, 0.0f, 0.25f, 0.0f, 0.0f, 1.0f,		box_s, 0.0f,	0.0f, 0.0f, 1.0f,
			2.25f, 0.5f, 0.25f, 0.0f, 0.0f, 1.0f,		box_s, box_t,	0.0f, 0.0f, 1.0f,
			1.75f, 0.0f, 0.25f, 0.0f, 0.0f, 1.0f,		0.0f, 0.0f,		0.0f, 0.0f, 1.0f,

			1.75f, 0.0f, 0.25f, 0.0f, 0.0f, 1.0f,		0.0f, 0.0f,		0.0f, 0.0f, 1.0f,
			2.25f, 0.5f, 0.25f, 0.0f, 0.0f, 1.0f,		box_s, box_t,	0.0f, 0.0f, 1.0f,
			1.75f, 0.5f, 0.25f, 0.0f, 0.0f, 1.0f,		0.0f, box_t,	0.0f, 0.0f, 1.0f,
			// 좌측면
			1.75f, 0.0f, 0.25f, 1.0f, 0.0f, 1.0f,		box_s, 0.0f,	-1.0f, 0.0f, 0.0f,
			1.75f, 0.5f, 0.25f, 1.0f, 0.0f, 1.0f,		box_s, box_t,	-1.0f, 0.0f, 0.0f,
			1.75f, 0.0f, -0.25f, 1.0f, 0.0f, 1.0f,		0.0f, 0.0f,		-1.0f, 0.0f, 0.0f,

			1.75f, 0.0f, -0.25f, 1.0f, 0.0f, 1.0f,		0.0f, 0.0f,		-1.0f, 0.0f, 0.0f,
			1.75f, 0.5f, 0.25f, 1.0f, 0.0f, 1.0f,		box_s, box_t,	-1.0f, 0.0f, 0.0f,
			1.75f, 0.5f, -0.25f, 1.0f, 0.0f, 1.0f,		0.0f, box_t,	-1.0f, 0.0f, 0.0f,
			// 바닥면
			1.75f, 0.0f, 0.25f, 1.0f, 1.0f, 0.0f,		box_s, 0.0f,	0.0f, -1.0f, 0.0f,
			2.25f, 0.0f, -0.25f, 1.0f, 1.0f, 0.0f,		0.0f, box_t,	0.0f, -1.0f, 0.0f,
			2.25f, 0.0f, 0.25f, 1.0f, 1.0f, 0.0f,		0.0f, 0.0f,		0.0f, -1.0f, 0.0f,

			2.25f, 0.0f, -0.25f, 1.0f, 1.0f, 0.0f,		0.0f, box_t,	0.0f, -1.0f, 0.0f,
			1.75f, 0.0f, 0.25f, 1.0f, 1.0f, 0.0f,		box_s, 0.0,		0.0f, -1.0f, 0.0f,
			1.75f, 0.0f, -0.25f, 1.0f, 1.0f, 0.0f,		box_s, box_t,	0.0f, -1.0f, 0.0f,
			// 윗면
			1.75f, 0.5f, -0.25f, 0.0f, 1.0f, 1.0f,		0.0f, box_t,	0.0f, 1.0f, 0.0f,
			2.25f, 0.5f, 0.25f, 0.0f, 1.0f, 1.0f,		box_s, 0.0f,	0.0f, 1.0f, 0.0f,
			2.25f, 0.5f, -0.25f, 0.0f, 1.0f, 1.0f,		box_s, box_t,	0.0f, 1.0f, 0.0f,

			2.25f, 0.5f, 0.25f, 0.0f, 1.0f, 1.0f,		box_s, 0.0f,	0.0f, 1.0f, 0.0f,
			1.75f, 0.5f, -0.25f, 0.0f, 1.0f, 1.0f,		0.0f, box_t,	0.0f, 1.0f, 0.0f,
			1.75f, 0.5f, 0.25f, 0.0f, 1.0f, 1.0f,		0.0f, 0.0f,		0.0f, 1.0f, 0.0f
		};

		// VBO를 생성하여 vertices 값들을 복사
		glBindBuffer(GL_ARRAY_BUFFER, VBOs[1]);
		glBufferData(GL_ARRAY_BUFFER, sizeof(box_vertices), box_vertices, GL_STATIC_DRAW);

		// VBO를 나누어서 각 버텍스 속성으로 연결
		// 위치 속성 (location = 0)
		glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 11 * sizeof(float), (void*)0);
		glEnableVertexAttribArray(0);
		// 컬러 속성 (location = 1)
		glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 11 * sizeof(float), (void*)(3 * sizeof(float)));
		glEnableVertexAttribArray(1);
		// 텍스처 좌표 속성 (location = 2)
		glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 11 * sizeof(float), (void*)(6 * sizeof(float)));
		glEnableVertexAttribArray(2);
		// 노멀 속성 (location = 3)
		glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE, 11 * sizeof(float), (void*)(8 * sizeof(float)));
		glEnableVertexAttribArray(3);

		// VBO 및 버텍스 속성을 다 했으니 VBO와 VAO를 unbind한다.
		glBindBuffer(GL_ARRAY_BUFFER, 0);
		glBindVertexArray(0);

		//  세 번째 객체 정의 : 피라미드 --------------------------------------------------
		glBindVertexArray(VAOs[2]);
		// 피라미드 점들의 위치와 컬러, 텍스처 좌표를 정의한다.
		GLfloat pyramid_vertices[] = {
			1.0f, 0.0f, -1.0f,    // 우측 상단
			-1.0f, 0.0f, -1.0f,   // 좌측 상단
			-1.0f, 0.0f, 1.0f,    // 좌측 하단
			1.0f, 0.0f, 1.0f,     // 우측 하단
			0.0f, 1.0f, 0.0f,      // 상단 꼭지점
			0.0f, -1.0f, 0.0f,      // 하단 꼭지점
		};

		// 삼각형으로 그릴 인덱스를 정의한다.
		GLuint pyramid_indices[] = {
			4, 0, 1,
			4, 1, 2,
			4, 2, 3,
			4, 3, 0,

			5, 1, 0,
			5, 2, 1,
			5, 3, 2,
			5, 0, 3,
		};

		// VBO를 생성하여 vertices 값들을 복사
		glBindBuffer(GL_ARRAY_BUFFER, VBOs[2]);
		glBufferData(GL_ARRAY_BUFFER, sizeof(pyramid_vertices), pyramid_vertices, GL_STATIC_DRAW);

		// VBO를 나누어서 각 버텍스 속성으로 연결
		// 위치 속성 (location = 0)
		glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
		glEnableVertexAttribArray(0);

		// EBO를 생성하고 indices 값들을 복사
		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBOs[1]);
		glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(pyramid_indices), pyramid_indices, GL_STATIC_DRAW);

		// VBO 및 버텍스 속성을 다 했으니 VBO와 VAO를 unbind한다.
		glBindVertexArray(0);
		glBindBuffer(GL_ARRAY_BUFFER, 0);
		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

	}

	// 애플리케이션 끝날 때 호출된다.
	virtual void shutdown()
	{
		glDeleteTextures(2, textures);
		glDeleteBuffers(2, EBOs);
		glDeleteBuffers(3, VBOs);
		glDeleteVertexArrays(3, VAOs);
		glDeleteProgram(shader_programs[1]);
		glDeleteProgram(shader_programs[2]);
	}

	// 렌더링 virtual 함수를 작성해서 오버라이딩한다.
	virtual void render(double currentTime)
	{
		const GLfloat black[] = { 0.0f, 0.0f, 0.0f, 1.0f };
		glClearBufferfv(GL_COLOR, 0, black);
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		glEnable(GL_DEPTH_TEST);
		glEnable(GL_CULL_FACE);

		//GLint uniform_transform2 = glGetUniformLocation(shader_programs[1], "transform");

		// 카메라 매트릭스 계산
		float distance = 2.f;
		vmath::vec3 eye((float)cos(currentTime * 1.f) * distance, 1.0, (float)sin(currentTime * 1.f) * distance);
		vmath::vec3 center(0.0, 0.0, 0.0);
		vmath::vec3 up(0.0, 1.0, 0.0);
		vmath::mat4 lookAt = vmath::lookat(eye, center, up);
		float fov = 50.f;
		vmath::mat4 projM = vmath::perspective(fov, info.windowWidth / (float)info.windowHeight, 0.1f, 1000.0f);

		// 라이팅 설정 ---------------------------------------
		vmath::vec3 lightPos = vmath::vec3(0.0f, 0.25f, 0.0f);// (0.0f, 0.5f, 0.0f);
		vmath::vec3 lightColor(1.0f, 1.0f, 1.0f);
		vmath::vec3 viewPos = eye;
		vmath::vec3 yellowboxColor(1.0f, 0.5f, 0.0f);
		vmath::vec3 puppleboxColor(0.5f, 0.0f, 1.0f);

		// 박스 그리기 ---------------------------------------
		float angle = currentTime * 100;

		vmath::mat4 transform = vmath::translate(-1.0f, 0.0f, 0.0f) *
			vmath::rotate(angle, 0.0f, 1.0f, 0.0f);

		glUseProgram(shader_programs[1]);

		glUniformMatrix4fv(glGetUniformLocation(shader_programs[1], "projection"), 1, GL_FALSE, projM);
		glUniformMatrix4fv(glGetUniformLocation(shader_programs[1], "view"), 1, GL_FALSE, lookAt);
		glUniformMatrix4fv(glGetUniformLocation(shader_programs[1], "model"), 1, GL_FALSE, transform);
		glUniform3fv(glGetUniformLocation(shader_programs[1], "lightPos"), 1, lightPos);
		glUniform3fv(glGetUniformLocation(shader_programs[1], "viewPos"), 1, viewPos);
		glUniform3fv(glGetUniformLocation(shader_programs[1], "lightColor"), 1, lightColor);
		glUniform3fv(glGetUniformLocation(shader_programs[1], "boxColor"), 1, yellowboxColor);
		glUniform1f(glGetUniformLocation(shader_programs[1], "shininess"), 64.f);

		glBindVertexArray(VAOs[1]);
		glDrawArrays(GL_TRIANGLES, 0, 36);

		transform = vmath::translate(1.0f, 0.0f, 0.0f) * vmath::rotate(angle, 0.0f, 1.0f, 0.0f);
		glUniformMatrix4fv(glGetUniformLocation(shader_programs[1], "model"), 1, GL_FALSE, transform);
		glUniform3fv(glGetUniformLocation(shader_programs[1], "boxColor"), 1, puppleboxColor);
		glUniform1f(glGetUniformLocation(shader_programs[1], "shininess"), 1.f);
		glDrawArrays(GL_TRIANGLES, 0, 36);

		//-----------------------------광원위치오브젝트
		float scaleFactor2 = 0.05f;
		vmath::mat4 rotateM2 = vmath::translate(0.0f, 0.5f, 0.0f) *
			vmath::rotate(angle, 0.0f, 1.0f, 0.0f) * vmath::scale(scaleFactor2, scaleFactor2, scaleFactor2);

		glUseProgram(shader_programs[2]);

		glUniform3fv(glGetUniformLocation(shader_programs[2], "color"), 1, lightColor);
		glUniformMatrix4fv(glGetUniformLocation(shader_programs[2], "projection"), 1, GL_FALSE, projM);
		glUniformMatrix4fv(glGetUniformLocation(shader_programs[2], "view"), 1, GL_FALSE, lookAt);
		glUniformMatrix4fv(glGetUniformLocation(shader_programs[2], "model"), 1, GL_FALSE, rotateM2);

		glBindVertexArray(VAOs[2]);
		glDrawElements(GL_TRIANGLES, 24, GL_UNSIGNED_INT, 0);

	}

private:
	GLuint shader_programs[3];
	GLuint VAOs[3], VBOs[3], EBOs[2];
	GLuint textures[3];
};

// DECLARE_MAIN의 하나뿐인 인스턴스
DECLARE_MAIN(my_application)

---

//<<<basic_lighting_vs.glsl>>>
#version 430 core
//상자
layout (location = 0) in vec3 pos;
layout (location = 1) in vec3 color;			
layout (location = 2) in vec2 texCoord;		
layout (location = 3) in vec3 normal; //노멀벡터

out vec3 vsPos;
out vec3 vsNormal;

uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;

void main()
{
    vsPos = vec3(model * vec4(pos, 1.0));
    vsNormal = mat3(transpose(inverse(model))) * normal;  
    
    gl_Position = projection * view * vec4(vsPos, 1.0);
}

//<<<basic_lighting_fs.glsl>>>
#version 430 core

in vec3 vsNormal;  
in vec3 vsPos;  
//상자
uniform vec3 lightPos; 
uniform vec3 viewPos; 
uniform vec3 lightColor;
uniform vec3 boxColor;
uniform float shininess;

out vec4 fragColor;

void main()
{
    // ambient 은은한 빛
    float ambientStrength = 0.1;
    vec3 ambient = ambientStrength * lightColor;
  	
    // diffuse 명암
    vec3 norm = normalize(vsNormal);
    vec3 lightDir = normalize(lightPos - vsPos);//빛의 방향 = 빛 위치 - 점 위치
    float diff = max(dot(norm, lightDir), 0.0);
    vec3 diffuse = diff * lightColor;
    
    // specular 반사 산란 정도
    float specularStrength = 1.0;
    vec3 viewDir = normalize(viewPos - vsPos);
    vec3 reflectDir = reflect(-lightDir, norm);  
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), shininess);
    vec3 specular = specularStrength * spec * lightColor;  
        
    vec3 result = (ambient + diffuse + specular) * boxColor;
    fragColor = vec4(result, 1.0);
}

//<<<simple_color_vs.glsl>>>
#version 430 core
//피라미드 광원
layout (location = 0) in vec3 pos;

out vec3 vsColor;

uniform vec3 color;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;

void main()
{
    gl_Position = projection * view * model * vec4(pos, 1.0);
	vsColor = color;
}

#version 430 core
//피라미드 광원
in vec3 vsColor;  

out vec4 fragColor;

void main()
{
    fragColor = vec4(vsColor, 1.0);
}

---

Phong 조명 모델 = ambient(전체적으로 은은한 빛) + diffuse(거리, 방향에 따른 명암) + specular(빛 반사)이다

이 떄 diffuse를 구하기 위해 면의 방향, 즉 노멀 벡터가 필요하므로 VBO 노멀속성으로 버테스쉐이더로 보낸다.

버텍스쉐이더에서 받아온 노멀벡터는 diffuse계산을 위해 처리하고 프래그먼트 쉐이더로 보내준다.

render에서 라이팅에 관련된 변수들을 선언한다

lightPos = 광원 위치

lightColor = 빛의 색상 (1, 1, 1) = 백색광

viewPos = 빛을 보는 위치

yellowboxColor = 박스의 색상

puppleboxColor = 박스의 색상

설정한 벡터 및 변수들은 uniform을 통해 프래그먼트 쉐이더로 보내준다.

프래그먼트 쉐이더에서 각각 ambient diffuse specular 값을 구해준 뒤 박스의 색상을 곱해 최종 벡터를 구한 뒤 출력한다.