OpenGL之——摄像机（五）FPS漫游

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main.cpp

#include <iostream>

// GLEW
#define GLEW_STATIC
#include <GL/glew.h>

// GLFW
#include <GLFW/glfw3.h>
// Other Libs
#include <SOIL.h>
#include <GL/glut.h>
// GLM Mathematics
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

#pragma comment(lib,"glew32s.lib")
#pragma comment(lib,"glfw3.lib")
#pragma comment(lib,"SOIL.lib")
// Other includes
#include "Shader.h"
#include "Camera.h"
using namespace std;



// Function prototypes
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
void do_movement();

// Window dimensions
GLuint screenWidth = 800, screenHeight = 600;

// Function prototypes
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void Do_Movement();

// Camera
Camera camera(glm::vec3(0.0f, 0.0f, 3.0f));
bool keys[1024];
GLfloat lastX = 400, lastY = 300;
bool firstMouse = true;

GLfloat deltaTime = 0.0f;
GLfloat lastFrame = 0.0f;

// The MAIN function, from here we start our application and run our Game loop
int main()
{
	// Init GLFW
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
	glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
	glfwWindowHint(GLFW_SAMPLES, 4);

	GLFWwindow* window = glfwCreateWindow(screenWidth, screenHeight, "LearnOpenGL", nullptr, nullptr); // Windowed
	glfwMakeContextCurrent(window);

	// Set the required callback functions
	glfwSetKeyCallback(window, key_callback);
	glfwSetCursorPosCallback(window, mouse_callback);
	glfwSetScrollCallback(window, scroll_callback);

	// Options
	glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);

	// Initialize GLEW to setup the OpenGL Function pointers
	glewExperimental = GL_TRUE;
	glewInit();

	// Define the viewport dimensions
	glViewport(0, 0, screenWidth, screenHeight);

	// Setup some OpenGL options
	glEnable(GL_DEPTH_TEST);

	// Setup and compile our shaders
	Shader ourShader("shader.vs", "shader.frag");

	// Set up our vertex data (and buffer(s)) and attribute pointers
	GLfloat vertices[] = {
		-0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
		 0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
		 0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
		 0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
		-0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
		-0.5f, -0.5f, -0.5f,  0.0f, 0.0f,

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

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

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

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

		-0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
		 0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
		 0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
		 0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
		-0.5f,  0.5f,  0.5f,  0.0f, 0.0f,
		-0.5f,  0.5f, -0.5f,  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)
	};

	GLuint VBO, VAO;
	glGenVertexArrays(1, &VAO);
	glGenBuffers(1, &VBO);
	// Bind our Vertex Array Object first, then bind and set our buffers and pointers.
	glBindVertexArray(VAO);

	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

	// Position attribute
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (GLvoid*)0);
	glEnableVertexAttribArray(0);
	// TexCoord attribute
	glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
	glEnableVertexAttribArray(2);

	glBindVertexArray(0); // Unbind VAO

	// Load and create a texture 
	GLuint texture1;
	GLuint texture2;
	// --== TEXTURE 1 == --
	glGenTextures(1, &texture1);
	glBindTexture(GL_TEXTURE_2D, texture1); // All upcoming GL_TEXTURE_2D operations now have effect on our texture object
	// Set our texture parameters
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	// Set texture filtering
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	// Load, create texture and generate mipmaps
	int width, height;
	unsigned char* image = SOIL_load_image("box.jpg", &width, &height, 0, SOIL_LOAD_RGB);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
	glGenerateMipmap(GL_TEXTURE_2D);
	SOIL_free_image_data(image);
	glBindTexture(GL_TEXTURE_2D, 0); // Unbind texture when done, so we won't accidentily mess up our texture.
	// --== TEXTURE 2 == --
	glGenTextures(1, &texture2);
	glBindTexture(GL_TEXTURE_2D, texture2);
	// Set our texture parameters
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	// Set texture filtering
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	// Load, create texture and generate mipmaps
	image = SOIL_load_image("face.png", &width, &height, 0, SOIL_LOAD_RGB);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
	glGenerateMipmap(GL_TEXTURE_2D);
	SOIL_free_image_data(image);
	glBindTexture(GL_TEXTURE_2D, 0);

	// Game loop
	while (!glfwWindowShouldClose(window))
	{
		// Set frame time
		GLfloat currentFrame = glfwGetTime();
		deltaTime = currentFrame - lastFrame;
		lastFrame = currentFrame;

		// Check and call events
		glfwPollEvents();
		Do_Movement();

		// Clear the colorbuffer
		glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

		// Draw our first triangle
		ourShader.Use();

		// Bind Textures using texture units
		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, texture1);
		glUniform1i(glGetUniformLocation(ourShader.Program, "ourTexture1"), 0);
		glActiveTexture(GL_TEXTURE1);
		glBindTexture(GL_TEXTURE_2D, texture2);
		glUniform1i(glGetUniformLocation(ourShader.Program, "ourTexture2"), 1);

		// Create camera transformation
		glm::mat4 view;
		view = camera.GetViewMatrix();
		glm::mat4 projection;
		projection = glm::perspective(camera.Zoom, (float)screenWidth / (float)screenHeight, 0.1f, 1000.0f);
		// Get the uniform locations
		GLint modelLoc = glGetUniformLocation(ourShader.Program, "model");
		GLint viewLoc = glGetUniformLocation(ourShader.Program, "view");
		GLint projLoc = glGetUniformLocation(ourShader.Program, "projection");
		// Pass the matrices to the shader
		glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
		glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(projection));

		glBindVertexArray(VAO);
		for (GLuint i = 0; i < 10; i++)
		{
			// Calculate the model matrix for each object and pass it to shader before drawing
			glm::mat4 model;
			model = glm::translate(model, cubePositions[i]);
			GLfloat angle = 20.0f * i * glfwGetTime();
			model = glm::rotate(model, angle, glm::vec3(1.0f, 0.3f, 0.5f));
			glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));

			glDrawArrays(GL_TRIANGLES, 0, 36);
		}
		glBindVertexArray(0);
		// Swap the buffers
		glfwSwapBuffers(window);
	}
	// Properly de-allocate all resources once they've outlived their purpose
	glDeleteVertexArrays(1, &VAO);
	glDeleteBuffers(1, &VBO);
	glfwTerminate();
	return 0;
}

// Moves/alters the camera positions based on user input
void Do_Movement()
{
	// Camera controls
	if (keys[GLFW_KEY_W])
		camera.ProcessKeyboard(FORWARD, deltaTime);
	if (keys[GLFW_KEY_S])
		camera.ProcessKeyboard(BACKWARD, deltaTime);
	if (keys[GLFW_KEY_A])
		camera.ProcessKeyboard(LEFT, deltaTime);
	if (keys[GLFW_KEY_D])
		camera.ProcessKeyboard(RIGHT, deltaTime);
}

// Is called whenever a key is pressed/released via GLFW
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
	//cout << key << endl;
	if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
		glfwSetWindowShouldClose(window, GL_TRUE);
	if (key >= 0 && key < 1024)
	{
		if (action == GLFW_PRESS)
			keys[key] = true;
		else if (action == GLFW_RELEASE)
			keys[key] = false;
	}
}

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

	GLfloat xoffset = xpos - lastX;
	GLfloat yoffset = lastY - ypos;  // Reversed since y-coordinates go from bottom to left

	lastX = xpos;
	lastY = ypos;

	camera.ProcessMouseMovement(xoffset, yoffset);
}


void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
	camera.ProcessMouseScroll(yoffset);
}

Camera.h

#pragma once
#include <iostream>
// Std. Includes
#include <vector>

// GL Includes
#include <GL/glew.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
using namespace std;


// Defines several possible options for camera movement. Used as abstraction to stay away from window-system specific input methods
enum Camera_Movement {
	FORWARD,
	BACKWARD,
	LEFT,
	RIGHT
};

// Default camera values
const GLfloat YAW = -90.0f;
const GLfloat PITCH = 0.0f;
const GLfloat SPEED = 3.0f;
const GLfloat SENSITIVTY = 0.25f;
const GLfloat ZOOM = 45.0f;


// An abstract camera class that processes input and calculates the corresponding Eular Angles, Vectors and Matrices for use in OpenGL
class Camera
{
public:
	// Camera Attributes
	glm::vec3 Position;
	glm::vec3 Front;
	glm::vec3 Up;
	glm::vec3 Right;
	glm::vec3 WorldUp;
	// Eular Angles
	GLfloat Yaw;
	GLfloat Pitch;
	// Camera options
	GLfloat MovementSpeed;
	GLfloat MouseSensitivity;
	GLfloat Zoom;

	// Constructor with vectors
	Camera(glm::vec3 position = glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3 up = glm::vec3(0.0f, 1.0f, 0.0f), GLfloat yaw = YAW, GLfloat pitch = PITCH) : Front(glm::vec3(0.0f, 0.0f, -1.0f)), MovementSpeed(SPEED), MouseSensitivity(SENSITIVTY), Zoom(ZOOM)
	{
		this->Position = position;
		this->WorldUp = up;
		this->Yaw = yaw;
		this->Pitch = pitch;
		this->updateCameraVectors();
	}
	// Constructor with scalar values
	Camera(GLfloat posX, GLfloat posY, GLfloat posZ, GLfloat upX, GLfloat upY, GLfloat upZ, GLfloat yaw, GLfloat pitch) : Front(glm::vec3(0.0f, 0.0f, -1.0f)), MovementSpeed(SPEED), MouseSensitivity(SENSITIVTY), Zoom(ZOOM)
	{
		this->Position = glm::vec3(posX, posY, posZ);
		this->WorldUp = glm::vec3(upX, upY, upZ);
		this->Yaw = yaw;
		this->Pitch = pitch;
		this->updateCameraVectors();
	}

	// Returns the view matrix calculated using Eular Angles and the LookAt Matrix
	glm::mat4 GetViewMatrix()
	{
		return glm::lookAt(this->Position, this->Position + this->Front, this->Up);
	}

	// Processes input received from any keyboard-like input system. Accepts input parameter in the form of camera defined ENUM (to abstract it from windowing systems)
	void ProcessKeyboard(Camera_Movement direction, GLfloat deltaTime)
	{
		GLfloat velocity = this->MovementSpeed * deltaTime;
		if (direction == FORWARD)
			this->Position += this->Front * velocity;
		if (direction == BACKWARD)
			this->Position -= this->Front * velocity;
		if (direction == LEFT)
			this->Position -= this->Right * velocity;
		if (direction == RIGHT)
			this->Position += this->Right * velocity;
		this->Position.y = 0.0f;
		cout << "x=" << this->Position.x << "y=" << this->Position.y << "z=" << this->Position.z << endl;
	}

	// Processes input received from a mouse input system. Expects the offset value in both the x and y direction.
	void ProcessMouseMovement(GLfloat xoffset, GLfloat yoffset, GLboolean constrainPitch = true)
	{
		xoffset *= this->MouseSensitivity;
		yoffset *= this->MouseSensitivity;

		this->Yaw += xoffset;
		this->Pitch += yoffset;

		// Make sure that when pitch is out of bounds, screen doesn't get flipped
		if (constrainPitch)
		{
			if (this->Pitch > 89.0f)
				this->Pitch = 89.0f;
			if (this->Pitch < -89.0f)
				this->Pitch = -89.0f;
		}

		// Update Front, Right and Up Vectors using the updated Eular angles
		this->updateCameraVectors();
	}

	// Processes input received from a mouse scroll-wheel event. Only requires input on the vertical wheel-axis
	void ProcessMouseScroll(GLfloat yoffset)
	{
		if (this->Zoom >= 1.0f && this->Zoom <= 45.0f)
			this->Zoom -= yoffset;
		if (this->Zoom <= 1.0f)
			this->Zoom = 1.0f;
		if (this->Zoom >= 45.0f)
			this->Zoom = 45.0f;
	}

private:
	// Calculates the front vector from the Camera's (updated) Eular Angles
	void updateCameraVectors()
	{
		// Calculate the new Front vector
		glm::vec3 front;
		front.x = cos(glm::radians(this->Yaw)) * cos(glm::radians(this->Pitch));
		front.y = sin(glm::radians(this->Pitch));
		front.z = sin(glm::radians(this->Yaw)) * cos(glm::radians(this->Pitch));
		this->Front = glm::normalize(front);
		// Also re-calculate the Right and Up vector
		this->Right = glm::normalize(glm::cross(this->Front, this->WorldUp));  // Normalize the vectors, because their length gets closer to 0 the more you look up or down which results in slower movement.
		this->Up = glm::normalize(glm::cross(this->Right, this->Front));
	}
};