OpenGL学习之光照贴图

在上一节中，我们提到不同的物体对光有不同的反应，实际上同一物体的部分往往不是同一种材料构成的，比如汽车的车身喷漆之后往往很光亮，车窗会部分反射周围的环境，而轮胎的橡胶部分则比较暗淡。为了更好的模拟现实中的物体接受光照效果，我们应该为物体的不同部分指定不同的材质属性，而不是整个物体共用一个材质。

不同的部分对应不同的材质，这有点类似于根据纹理坐标获取不同的纹素，我们采用与纹理坐标类似的light maps方法。也就是为物体的不同部分指定不同的坐标，这个坐标从light map获取不同的材质属性，对应漫反射有diffuse map,镜面反射有specular map。

以上部分参考OpenGL学习脚印

借用Unity3D中对light mapping的解释

light mapping：对一些静态的物体和光，预先计算存储，不必实时计算，这个过程叫作baking。baking的结果就是一张lightmapping贴图。

漫反射贴图（diffuse mapping）

类似于纹理坐标，要使用diffuse map，我们需要在顶点属性中添加纹理坐标，可以从这里获取。

我们使用LearnOpenGL CN中提供的有钢边框的木箱，并使用我们的LoadImageToGPU()函数来加载纹理

在着色器中，重新定义材质属性为

struct Material{
vec3 ambient;
sampler2D diffuse;
vec3 specular;
float shininess;
};
in vec3 FragPos;
in vec3 Normal;
in vec2 TexCoord;

物体材质方面，环境光一般和漫反射相同，只是强度不同，因此计算环境光和漫反射都使用diffuse map,如下所示

#version 330 core
struct Material{
vec3 ambient;
sampler2D diffuse;
vec3 specular;
float shininess;
};

in vec3 FragPos;
in vec3 Normal;
in vec2 TexCoord;

uniform vec3 objColor;
uniform vec3 ambientColor;
uniform vec3 lightPos;
uniform vec3 lightColor;
uniform vec3  CameraPos;
uniform Material material;

out vec4 FragColor;

void main()
{
	vec3 lightDir = normalize(lightPos-FragPos);
	vec3 reflectVec = reflect(-lightDir,Normal);
	vec3 CameraVec = normalize(CameraPos-FragPos);

	//specular
	float specularAmount = pow(max(dot(reflectVec,CameraVec),0),material.shininess);
	vec3 specular = material.specular * specularAmount * lightColor;
	//diffuse 
	vec3 diffuse =texture(material.diffuse,TexCoord).rgb * max( dot(lightDir,Normal),0) * lightColor;

	//ambient
	vec3 ambient = texture(material.diffuse,TexCoord).rgb*ambientColor;

	FragColor = vec4((diffuse + ambient + specular) * objColor,1.0);

}

更新顶点着色器来以顶点属性的形式接受纹理坐标，并将它们传递到片段着色器中：

#version 330 core
layout (location = 0) in vec3 aPos;
layout(location = 1) in vec3 aNormal;
layout(location=2) in vec2 aTexCoord;

uniform mat4 modelMat;
uniform mat4 viewMat;
uniform mat4 projMat;

//out vec2 TexCoord;
//out vec4 vertexColor;
out vec3 FragPos;
out vec3 Normal;
out vec2 TexCoord;

void main()
{
	gl_Position = projMat *  viewMat * modelMat * vec4(aPos, 1.0);
	FragPos= (modelMat * vec4(aPos.xyz,1.0)).xyz;
	Normal = mat3(transpose(inverse(modelMat)))* aNormal;
	TexCoord=aTexCoord;
}

main函数

#include 
#include 

#include 
#include"Shader.h"
#include"Camera.h"

#include 
#include 
#include 

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#include"Material.h"
// settings
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT =600;

	#pragma region Camera Declare
Camera camera(glm::vec3(0, 0, 3.0f), glm::radians(-15.0f), glm::radians(180.0f), glm::vec3(0, 1.0f, 0));
#pragma endregion

	#pragma region Input Declare
float lastX;
float lastY;
bool firstMouse = true;

void processInput(GLFWwindow *window)
{
	if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
	{
		glfwSetWindowShouldClose(window, true);
	}
	if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
	{
		camera.speedZ = 0.1f;
	}
	else if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
	{
		camera.speedZ = -0.1f;
	}
	else
	{
		camera.speedZ = 0;
		if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
		{
			glfwSetWindowShouldClose(window, true);
		}
		if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
		{
			camera.speedX = 0.1f;
		}
		else if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
		{
			camera.speedX = -0.1f;
		}
		else
		{
			camera.speedX = 0;
		}
	}
	if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
	{
		glfwSetWindowShouldClose(window, true);
	}
	if (glfwGetKey(window, GLFW_KEY_Q) == GLFW_PRESS)
	{
		camera.speedY = -0.1f;
	}
	else if (glfwGetKey(window, GLFW_KEY_E) == GLFW_PRESS)
	{
		camera.speedY = 0.1f;
	}
	else
	{
		camera.speedY = 0;
	}
}

// glfw: whenever the window size changed (by OS or user resize) this callback function executes
// ---------------------------------------------------------------------------------------------
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
	// make sure the viewport matches the new window dimensions; note that width and 
	// height will be significantly larger than specified on retina displays.
	glViewport(0, 0, width, height);
}

void mouse_callback(GLFWwindow* window, double xpos, double ypos)
{
	if (firstMouse == true)
	{
		lastX = xpos;
		lastY = ypos;
		firstMouse = false;

	}
	float deltaX, deltaY;
	deltaX = xpos - lastX;
	deltaY = ypos - lastY;

	lastX = xpos;
	lastY = ypos;
	camera.ProcessMouseMovement(deltaX, deltaY);

}

#pragma endregion

unsigned int LoadImageToGPU(const char*filename, GLint internalformat, GLenum format, int textureSlot)
{
	unsigned int texBuffer;
	glGenTextures(1, &texBuffer);
	glActiveTexture(GL_TEXTURE0 + textureSlot);
	glBindTexture(GL_TEXTURE_2D, texBuffer);

	int width, height, nrChannels;
	stbi_set_flip_vertically_on_load(true); // tell stb_image.h to flip loaded texture's on the y-axis.
	unsigned char *data = stbi_load(filename, &width, &height, &nrChannels, 0);
	if (data)
	{
		glTexImage2D(GL_TEXTURE_2D, 0, internalformat, width, height, 0, format, GL_UNSIGNED_BYTE, data);
		glGenerateMipmap(GL_TEXTURE_2D);
	}
	else
	{
		std::cout << "Failed to load texture" << std::endl;
	}
	stbi_image_free(data);
	return texBuffer;
}
int main()
{
	#pragma region Open a window
	// glfw: initialize and configure
	// ------------------------------
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

														
	GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
	if (window == NULL)
	{
		std::cout << "Failed to create GLFW window" << std::endl;
		glfwTerminate();
		return -1;
	}
	glfwMakeContextCurrent(window);
	glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
	glfwSetCursorPosCallback(window, mouse_callback);
	glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
	// glad: load all OpenGL function pointers
	// ---------------------------------------
	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
	{
		std::cout << "Failed to initialize GLAD" << std::endl;
		return -1;
	}

	// configure global opengl state
	// -----------------------------
	glEnable(GL_DEPTH_TEST);
#pragma endregion
	
	
	#pragma region Model Data
	GLfloat vertices[] = {
		// positions          // normals           // texture coords
		   -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  0.0f,  0.0f,
			0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  1.0f,  0.0f,
			0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  1.0f,  1.0f,
			0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  1.0f,  1.0f,
		   -0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  0.0f,  1.0f,
		   -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  0.0f,  0.0f,

		   -0.5f, -0.5f,  0.5f,  0.0f,  0.0f,  1.0f,  0.0f,  0.0f,
			0.5f, -0.5f,  0.5f,  0.0f,  0.0f,  1.0f,  1.0f,  0.0f,
			0.5f,  0.5f,  0.5f,  0.0f,  0.0f,  1.0f,  1.0f,  1.0f,
			0.5f,  0.5f,  0.5f,  0.0f,  0.0f,  1.0f,  1.0f,  1.0f,
		   -0.5f,  0.5f,  0.5f,  0.0f,  0.0f,  1.0f,  0.0f,  1.0f,
		   -0.5f, -0.5f,  0.5f,  0.0f,  0.0f,  1.0f,  0.0f,  0.0f,

		   -0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,  1.0f,  0.0f,
		   -0.5f,  0.5f, -0.5f, -1.0f,  0.0f,  0.0f,  1.0f,  1.0f,
		   -0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,  0.0f,  1.0f,
		   -0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,  0.0f,  1.0f,
		   -0.5f, -0.5f,  0.5f, -1.0f,  0.0f,  0.0f,  0.0f,  0.0f,
		   -0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,  1.0f,  0.0f,

			0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,  1.0f,  0.0f,
			0.5f,  0.5f, -0.5f,  1.0f,  0.0f,  0.0f,  1.0f,  1.0f,
			0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,  0.0f,  1.0f,
			0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,  0.0f,  1.0f,
			0.5f, -0.5f,  0.5f,  1.0f,  0.0f,  0.0f,  0.0f,  0.0f,
			0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,  1.0f,  0.0f,

		   -0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,  0.0f,  1.0f,
			0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,  1.0f,  1.0f,
			0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,  1.0f,  0.0f,
			0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,  1.0f,  0.0f,
		   -0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,  0.0f,  0.0f,
		   -0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,  0.0f,  1.0f,

		   -0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,  0.0f,  1.0f,
			0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,  1.0f,  1.0f,
			0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,  1.0f,  0.0f,
			0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,  1.0f,  0.0f,
		   -0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,  0.0f,  0.0f,
		   -0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,  0.0f,  1.0f

	};

	glm::vec3 cubePositions[] = {
		glm::vec3(0.0f,  0.0f,  0.0f),
		glm::vec3(2.0f,  5.0f, -15.0f),
		glm::vec3(-1.5f, -2.2f, -2.5f),
		glm::vec3(-3.8f, -2.0f, -12.3f),
		glm::vec3(2.4f, -0.4f, -3.5f),
		glm::vec3(-1.7f,  3.0f, -7.5f),
		glm::vec3(1.3f, -2.0f, -2.5f),
		glm::vec3(1.5f,  2.0f, -2.5f),
		glm::vec3(1.5f,  0.2f, -1.5f),
		glm::vec3(-1.3f,  1.0f, -1.5f)
	};
#pragma endregion
	
	#pragma region Init Shader Pragram
	Shader *ourShader = new Shader("VertexSource.vert", "fragmentSource.frag");

	#pragma region Init Material
	Material* myMaterial = new Material(ourShader,
		LoadImageToGPU("container2.png",GL_RGBA,GL_RGBA,0),
		glm::vec3(1.0f, 1.0f, 1.0f), 
		glm::vec3(0, 1.0f, 0),
		32.0f);
#pragma endregion

#pragma endregion

	#pragma region Init and Load Models to VAO,VBO 
	unsigned int  VAO;
	glGenVertexArrays(1, &VAO);
	glBindVertexArray(VAO);

	unsigned int VBO;
	glGenBuffers(1, &VBO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);


	// position attribute
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);
	
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
	glEnableVertexAttribArray(1);

	glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
	glEnableVertexAttribArray(2);

#pragma endregion

	#pragma region Init and Load Texture
	/*unsigned int texBufferA;
	texBufferA = LoadImageToGPU("container.jpg",GL_RGB,GL_RGB,0);
	unsigned int texBufferB;
	texBufferB = LoadImageToGPU("awesomeface.png",GL_RGBA, GL_RGBA, 1);*/
#pragma endregion
	// tell opengl for each sampler to which texture unit it belongs to (only has to be done once)
	// -------------------------------------------------------------------------------------------
	#pragma region Prepare MVP matrices
	glm::mat4 modelMat;
	glm::mat4 viewMat;
	glm::mat4 projMat;
	projMat = glm::perspective(glm::radians(45.0f), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
#pragma endregion
	// render loop
	// -----------
	while (!glfwWindowShouldClose(window))
	{
		// input
		processInput(window);

		// clear srceen 
		glClearColor(0, 0, 0, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // also clear the depth buffer now!


		viewMat = camera.GetViewMatrix();
		
		for (unsigned int i = 0; i < 10; i++)
		{
			//set Model Matrix
			modelMat = glm::translate(glm::mat4(1.0f), cubePositions[i]);
			//set View and Project Matrices here

			//set Material->shader program
			ourShader->use();
			//set Material->textures																								
			/*glActiveTexture(GL_TEXTURE0);
			glBindTexture(GL_TEXTURE_2D, texBufferA);
			glActiveTexture(GL_TEXTURE1);
			glBindTexture(GL_TEXTURE_2D, texBufferB);*/
			//set material->uniforms
		/*	glUniform1i(glGetUniformLocation(ourShader.ID, "ourTexture"), 0);
			glUniform1i(glGetUniformLocation(ourShader.ID, "ourFace"), 1);*/
			unsigned int modelLoc = glGetUniformLocation(ourShader->ID, "modelMat");
			unsigned int viewLoc = glGetUniformLocation(ourShader->ID, "viewMat");
			unsigned int projectLoc = glGetUniformLocation(ourShader->ID, "projMat");
			glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(modelMat));
			glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(viewMat));
			glUniformMatrix4fv(projectLoc, 1, GL_FALSE, glm::value_ptr(projMat));
			glUniform3f(glGetUniformLocation(ourShader->ID, "objColor"), 1.0f, 1.0f, 1.0f);
			glUniform3f(glGetUniformLocation(ourShader->ID, "ambientColor"), 0.5f,0.5f,0.5f);
			glUniform3f(glGetUniformLocation(ourShader->ID, "lightPos"), 10.0f, 10.0f, -5.0f);
			glUniform3f(glGetUniformLocation(ourShader->ID, "lightColor"), 1.0f, 1.0f, 1.0f);
			glUniform3f(glGetUniformLocation(ourShader->ID, "CameraPos"), camera.Position.x, camera.Position.y, camera.Position.z);

			myMaterial->shader->SetUniform3f("material.ambient", myMaterial->ambient);
			//myMaterial->shader->SetUniform3f("material.diffuse", myMaterial->diffuse);
			myMaterial->shader->SetUniform1f("material.shininess", myMaterial->shininess);
			myMaterial->shader->SetUniform3f("material.specular", myMaterial->specular);
			myMaterial->shader->SetUniform1i("material.diffuse", 0);
			// set Model
			glBindVertexArray(VAO);

			//Drawcall
			glDrawArrays(GL_TRIANGLES, 0, 36);
		}

		//Clean up,prepare for next render loop
		glfwSwapBuffers(window);
		glfwPollEvents();
		camera.UpdataCameraPos();
	}

	// optional: de-allocate all resources once they've outlived their purpose:
	// ------------------------------------------------------------------------
	glDeleteVertexArrays(1, &VAO);
	glDeleteBuffers(1, &VBO);
	// glfw: terminate, clearing all previously allocated GLFW resources.
	// ------------------------------------------------------------------
	glfwTerminate();
	return 0;
}

镜面光贴图

假设我们想要一个由钢做成的边架的木制容器，当接受镜面光时，刚架子很亮，而木制部分镜面光比较弱，要达到这一效果，我们可以为钢架子指定较强的强度，而木制部分强度较弱。使用类似于漫反射贴图的specualr map方法。

使用LearnOpenGL CN提供的镜面光贴图

在着色器中使用specualr map和diffuse map完成光照计算过程

#version 330 core
struct Material{
vec3 ambient;
sampler2D diffuse;
sampler2D specular;
float shininess;
};

in vec3 FragPos;
in vec3 Normal;
in vec2 TexCoord;

uniform vec3 objColor;
uniform vec3 ambientColor;
uniform vec3 lightPos;
uniform vec3 lightColor;
uniform vec3  CameraPos;
uniform Material material;

out vec4 FragColor;

void main()
{
	vec3 lightDir = normalize(lightPos-FragPos);
	vec3 reflectVec = reflect(-lightDir,Normal);
	vec3 CameraVec = normalize(CameraPos-FragPos);

	//specular
	float specularAmount = pow(max(dot(reflectVec,CameraVec),0),material.shininess);
	vec3 specular = texture(material.specular,TexCoord).rgb * specularAmount * lightColor;
	//diffuse 
	vec3 diffuse =texture(material.diffuse,TexCoord).rgb * max( dot(lightDir,Normal),0) * lightColor;

	//ambient
	vec3 ambient = texture(material.diffuse,TexCoord).rgb*ambientColor;

	FragColor = vec4((diffuse + ambient + specular) * objColor,1.0);

}

有所改动的material类

material.h

#pragma once
#include"Shader.h"
#include 
#include 
#include 
class Material
{
public:
	Shader *shader;
	unsigned int diffuse;
	unsigned int specular;
	glm::vec3 ambient;
	float shininess;

	Material(Shader* _shader, unsigned int _diffuse, unsigned int _specular,glm::vec3 _ambient,float _shininess);
	~Material();
};

material.cpp

#include "Material.h"





Material::Material(Shader * _shader, unsigned int _diffuse, unsigned int _specular, glm::vec3 _ambient, float _shininess)
	:shader(_shader),
	diffuse(_diffuse),
	specular(_specular),
	ambient(_ambient),
	shininess(_shininess)
{

}


Material::~Material()
{
}

main.cpp

#include 
#include 

#include 
#include"Shader.h"
#include"Camera.h"

#include 
#include 
#include 

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#include"Material.h"
// settings
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT =600;

	#pragma region Camera Declare
Camera camera(glm::vec3(0, 0, 3.0f), glm::radians(-15.0f), glm::radians(180.0f), glm::vec3(0, 1.0f, 0));
#pragma endregion

	#pragma region Input Declare
float lastX;
float lastY;
bool firstMouse = true;

void processInput(GLFWwindow *window)
{
	if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
	{
		glfwSetWindowShouldClose(window, true);
	}
	if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
	{
		camera.speedZ = 0.1f;
	}
	else if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
	{
		camera.speedZ = -0.1f;
	}
	else
	{
		camera.speedZ = 0;
		if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
		{
			glfwSetWindowShouldClose(window, true);
		}
		if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
		{
			camera.speedX = 0.1f;
		}
		else if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
		{
			camera.speedX = -0.1f;
		}
		else
		{
			camera.speedX = 0;
		}
	}
	if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
	{
		glfwSetWindowShouldClose(window, true);
	}
	if (glfwGetKey(window, GLFW_KEY_Q) == GLFW_PRESS)
	{
		camera.speedY = -0.1f;
	}
	else if (glfwGetKey(window, GLFW_KEY_E) == GLFW_PRESS)
	{
		camera.speedY = 0.1f;
	}
	else
	{
		camera.speedY = 0;
	}
}

// glfw: whenever the window size changed (by OS or user resize) this callback function executes
// ---------------------------------------------------------------------------------------------
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
	// make sure the viewport matches the new window dimensions; note that width and 
	// height will be significantly larger than specified on retina displays.
	glViewport(0, 0, width, height);
}

void mouse_callback(GLFWwindow* window, double xpos, double ypos)
{
	if (firstMouse == true)
	{
		lastX = xpos;
		lastY = ypos;
		firstMouse = false;

	}
	float deltaX, deltaY;
	deltaX = xpos - lastX;
	deltaY = ypos - lastY;

	lastX = xpos;
	lastY = ypos;
	camera.ProcessMouseMovement(deltaX, deltaY);

}


// utility function for loading a 2D texture from file
// ---------------------------------------------------
unsigned int loadTexture(char const * path)
{
	unsigned int textureID;
	glGenTextures(1, &textureID);

	int width, height, nrComponents;
	unsigned char *data = stbi_load(path, &width, &height, &nrComponents, 0);
	if (data)
	{
		GLenum format;
		if (nrComponents == 1)
			format = GL_RED;
		else if (nrComponents == 3)
			format = GL_RGB;
		else if (nrComponents == 4)
			format = GL_RGBA;

		glBindTexture(GL_TEXTURE_2D, textureID);
		glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
		glGenerateMipmap(GL_TEXTURE_2D);

		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

		stbi_image_free(data);
	}
	else
	{
		std::cout << "Texture failed to load at path: " << path << std::endl;
		stbi_image_free(data);
	}

	return textureID;
}

#pragma endregion

unsigned int LoadImageToGPU(const char*filename, GLint internalformat, GLenum format, int textureSlot)
{
	unsigned int texBuffer;
	glGenTextures(1, &texBuffer);
	glActiveTexture(GL_TEXTURE0 + textureSlot);
	glBindTexture(GL_TEXTURE_2D, texBuffer);

	int width, height, nrChannels;
	stbi_set_flip_vertically_on_load(true); // tell stb_image.h to flip loaded texture's on the y-axis.
	unsigned char *data = stbi_load(filename, &width, &height, &nrChannels, 0);
	if (data)
	{
		glTexImage2D(GL_TEXTURE_2D, 0, internalformat, width, height, 0, format, GL_UNSIGNED_BYTE, data);
		glGenerateMipmap(GL_TEXTURE_2D);
	}
	else
	{
		std::cout << "Failed to load texture" << std::endl;
	}
	stbi_image_free(data);
	return texBuffer;
}
int main()
{
	#pragma region Open a window
	// glfw: initialize and configure
	// ------------------------------
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

														
	GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
	if (window == NULL)
	{
		std::cout << "Failed to create GLFW window" << std::endl;
		glfwTerminate();
		return -1;
	}
	glfwMakeContextCurrent(window);
	glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
	glfwSetCursorPosCallback(window, mouse_callback);
	glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

	// glad: load all OpenGL function pointers
	// ---------------------------------------
	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
	{
		std::cout << "Failed to initialize GLAD" << std::endl;
		return -1;
	}

	// configure global opengl state
	// -----------------------------
	glEnable(GL_DEPTH_TEST);
#pragma endregion
	
	
	#pragma region Model Data
	GLfloat vertices[] = {
		// positions          // normals           // texture coords
		   -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  0.0f,  0.0f,
			0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  1.0f,  0.0f,
			0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  1.0f,  1.0f,
			0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  1.0f,  1.0f,
		   -0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  0.0f,  1.0f,
		   -0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,  0.0f,  0.0f,

		   -0.5f, -0.5f,  0.5f,  0.0f,  0.0f,  1.0f,  0.0f,  0.0f,
			0.5f, -0.5f,  0.5f,  0.0f,  0.0f,  1.0f,  1.0f,  0.0f,
			0.5f,  0.5f,  0.5f,  0.0f,  0.0f,  1.0f,  1.0f,  1.0f,
			0.5f,  0.5f,  0.5f,  0.0f,  0.0f,  1.0f,  1.0f,  1.0f,
		   -0.5f,  0.5f,  0.5f,  0.0f,  0.0f,  1.0f,  0.0f,  1.0f,
		   -0.5f, -0.5f,  0.5f,  0.0f,  0.0f,  1.0f,  0.0f,  0.0f,

		   -0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,  1.0f,  0.0f,
		   -0.5f,  0.5f, -0.5f, -1.0f,  0.0f,  0.0f,  1.0f,  1.0f,
		   -0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,  0.0f,  1.0f,
		   -0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,  0.0f,  1.0f,
		   -0.5f, -0.5f,  0.5f, -1.0f,  0.0f,  0.0f,  0.0f,  0.0f,
		   -0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,  1.0f,  0.0f,

			0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,  1.0f,  0.0f,
			0.5f,  0.5f, -0.5f,  1.0f,  0.0f,  0.0f,  1.0f,  1.0f,
			0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,  0.0f,  1.0f,
			0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,  0.0f,  1.0f,
			0.5f, -0.5f,  0.5f,  1.0f,  0.0f,  0.0f,  0.0f,  0.0f,
			0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,  1.0f,  0.0f,

		   -0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,  0.0f,  1.0f,
			0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,  1.0f,  1.0f,
			0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,  1.0f,  0.0f,
			0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,  1.0f,  0.0f,
		   -0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,  0.0f,  0.0f,
		   -0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,  0.0f,  1.0f,

		   -0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,  0.0f,  1.0f,
			0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,  1.0f,  1.0f,
			0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,  1.0f,  0.0f,
			0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,  1.0f,  0.0f,
		   -0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,  0.0f,  0.0f,
		   -0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,  0.0f,  1.0f

	};

	glm::vec3 cubePositions[] = {
		glm::vec3(0.0f,  0.0f,  0.0f),
		glm::vec3(2.0f,  5.0f, -15.0f),
		glm::vec3(-1.5f, -2.2f, -2.5f),
		glm::vec3(-3.8f, -2.0f, -12.3f),
		glm::vec3(2.4f, -0.4f, -3.5f),
		glm::vec3(-1.7f,  3.0f, -7.5f),
		glm::vec3(1.3f, -2.0f, -2.5f),
		glm::vec3(1.5f,  2.0f, -2.5f),
		glm::vec3(1.5f,  0.2f, -1.5f),
		glm::vec3(-1.3f,  1.0f, -1.5f)
	};
#pragma endregion
	
	#pragma region Init Shader Pragram
	Shader *ourShader = new Shader("VertexSource.vert", "fragmentSource.frag");

	#pragma region Init Material
	Material* myMaterial = new Material(ourShader,
		LoadImageToGPU("container2.png",GL_RGBA,GL_RGBA,Shader::DIFFUSE),
		LoadImageToGPU("container2_specular.png", GL_RGBA, GL_RGBA, Shader::SPECULAR),
		glm::vec3(0, 1.0f, 0),
		32.0f);
#pragma endregion

#pragma endregion

	#pragma region Init and Load Models to VAO,VBO 
	unsigned int  VAO;
	glGenVertexArrays(1, &VAO);
	glBindVertexArray(VAO);

	unsigned int VBO;
	glGenBuffers(1, &VBO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);


	// position attribute
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);
	
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
	glEnableVertexAttribArray(1);

	glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
	glEnableVertexAttribArray(2);

#pragma endregion

	#pragma region Init and Load Texture
	/*unsigned int texBufferA;
	texBufferA = LoadImageToGPU("container.jpg",GL_RGB,GL_RGB,0);
	unsigned int texBufferB;
	texBufferB = LoadImageToGPU("awesomeface.png",GL_RGBA, GL_RGBA, 1);*/
#pragma endregion
	// tell opengl for each sampler to which texture unit it belongs to (only has to be done once)
	// -------------------------------------------------------------------------------------------
	#pragma region Prepare MVP matrices
	glm::mat4 modelMat;
	glm::mat4 viewMat;
	glm::mat4 projMat;
	projMat = glm::perspective(glm::radians(45.0f), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
#pragma endregion
	// render loop
	// -----------
	while (!glfwWindowShouldClose(window))
	{
		// input
		processInput(window);

		// clear srceen 
		glClearColor(0, 0, 0, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // also clear the depth buffer now!


		viewMat = camera.GetViewMatrix();
		
		for (unsigned int i = 0; i < 10; i++)
		{
			//set Model Matrix
			modelMat = glm::translate(glm::mat4(1.0f), cubePositions[i]);
			//set View and Project Matrices here

			//set Material->shader program
			ourShader->use();
			//set Material->textures																								
			glActiveTexture(GL_TEXTURE0);
			glBindTexture(GL_TEXTURE_2D, myMaterial->diffuse);
			glActiveTexture(GL_TEXTURE0+1);
			glBindTexture(GL_TEXTURE_2D, myMaterial->specular);
			//set material->uniforms
		/*	glUniform1i(glGetUniformLocation(ourShader.ID, "ourTexture"), 0);
			glUniform1i(glGetUniformLocation(ourShader.ID, "ourFace"), 1);*/
			unsigned int modelLoc = glGetUniformLocation(ourShader->ID, "modelMat");
			unsigned int viewLoc = glGetUniformLocation(ourShader->ID, "viewMat");
			unsigned int projectLoc = glGetUniformLocation(ourShader->ID, "projMat");
			glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(modelMat));
			glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(viewMat));
			glUniformMatrix4fv(projectLoc, 1, GL_FALSE, glm::value_ptr(projMat));
			glUniform3f(glGetUniformLocation(ourShader->ID, "objColor"), 1.0f, 1.0f, 1.0f);
			glUniform3f(glGetUniformLocation(ourShader->ID, "ambientColor"), 0.5f,0.5f,0.5f);
			glUniform3f(glGetUniformLocation(ourShader->ID, "lightPos"), 10.0f, 10.0f, -5.0f);
			glUniform3f(glGetUniformLocation(ourShader->ID, "lightColor"), 1.0f, 1.0f, 1.0f);
			glUniform3f(glGetUniformLocation(ourShader->ID, "CameraPos"), camera.Position.x, camera.Position.y, camera.Position.z);

			myMaterial->shader->SetUniform3f("material.ambient", myMaterial->ambient);
			//myMaterial->shader->SetUniform3f("material.diffuse", myMaterial->diffuse);
			myMaterial->shader->SetUniform1f("material.shininess", myMaterial->shininess);
			//myMaterial->shader->SetUniform3f("material.specular", myMaterial->specular);
			myMaterial->shader->SetUniform1i("material.diffuse", Shader::DIFFUSE);
			myMaterial->shader->SetUniform1i("material.specular",Shader::SPECULAR);

			// set Model
			glBindVertexArray(VAO);

			//Drawcall
			glDrawArrays(GL_TRIANGLES, 0, 36);
		}

		//Clean up,prepare for next render loop
		glfwSwapBuffers(window);
		glfwPollEvents();
		camera.UpdataCameraPos();
	}

	// optional: de-allocate all resources once they've outlived their purpose:
	// ------------------------------------------------------------------------
	glDeleteVertexArrays(1, &VAO);
	glDeleteBuffers(1, &VBO);
	// glfw: terminate, clearing all previously allocated GLFW resources.
	// ------------------------------------------------------------------
	glfwTerminate();
	return 0;
}