c++ - 我想知道缩放和轨道哪里出了问题
问题描述
我希望能够平移、缩放和环绕立方体。我想知道为什么立方体在屏幕上显示为完全缩放，以至于我必须向后移动才能查看整个立方体。我还想将缩放控件更改为 alt 和鼠标右键以进行缩放和环绕，但我无法让它工作。任何援助将不胜感激。
/*/header inclusions*/
#include <iostream> // Includes C++ i/o stream
#include <GL/glew.h> // Includes glew header
#include <GL/freeglut.h> // Includes freeglut header
// GLM Math inclusions
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include<glm/gtc/type_ptr.hpp>
using namespace std; // Uses the standard namespace
#define WINDOW_TITLE "Modern OpenGL" // Macro for window title
//Vertex and fragment shader
#ifndef GLSL
#define GLSL(Version, source) "#version " #Version "\n" #source
#endif
// Variables for window width and height
GLint ShaderProgram, WindowWidth = 800, WindowHeight = 600;
GLuint VBO, VAO;
GLfloat cameraSpeed = 0.0005f;
GLchar currentKey;
GLfloat lastMouseX = 400, lastMouseY = 300;
GLfloat mouseXOffset, mouseYOffset, yaw = 0.0f, pitch = 0.0f;
GLfloat sensitivity = 0.5f;
bool mouseDetected = true;
//global vectors declaration
glm::vec3 cameraPosition = glm::vec3(0.0f,0.0f,0.0f);
glm::vec3 CameraUpY = glm::vec3(0.0f,1.0f,0.0f);
glm::vec3 CameraForwardZ = glm::vec3(0.0f,0.0f,-1.0f);
glm::vec3 front;
/* User-defined Function prototypes to:*/
void UResizeWindow(int,int);
void URenderGraphics(void);
void UCreateShader(void);
void UCreateBuffers(void);
void UKeyboard(unsigned char key, int x, int y);
void UKeyReleased(unsigned char key, int x, int y);
void UMouseMove(int x, int y);
/*Vertex shader source code*/
const GLchar * vertexShaderSource = GLSL(330,
layout(location=0) in vec3 position;
layout(location=1) in vec3 color;
out vec3 mobileColor; //declare a vec 4 variable
//Global variables for the transform matrices
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main(){
gl_Position = projection * view * model * vec4(position, 1.0f);//transform vertices
mobileColor = color;
}
);
/*Fragment shader program source code*/
const GLchar * fragmentShaderSource = GLSL(330,
in vec3 mobileColor;
out vec4 gpuColor;//out vertex_Color;
void main(){
gpuColor = vec4 (mobileColor, 1.0);
}
);
//main program
int main(int argc, char* argv[])
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
glutInitWindowSize(WindowWidth, WindowHeight);
glutCreateWindow(WINDOW_TITLE);
glutReshapeFunc(UResizeWindow);
glewExperimental = GL_TRUE;
if (glewInit()!= GLEW_OK)
{
std::cout << "Failed to initialize GLEW" << std::endl;
return -1;
}
UCreateShader();
UCreateBuffers();
// Use the Shader program
glUseProgram(ShaderProgram);
glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // Set background color
glutDisplayFunc(URenderGraphics);
glutKeyboardFunc(UKeyboard);
glutKeyboardUpFunc(UKeyReleased);
glutPassiveMotionFunc(UMouseMove);
glutMainLoop();
// Destroys Buffer objects once used
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
return 0;
}
/* Resizes the window*/
void UResizeWindow(int w, int h)
{
WindowWidth = w;
WindowHeight = h;
glViewport(0, 0, WindowWidth, WindowHeight);
}
/* Renders graphics */
void URenderGraphics(void)
{
glEnable(GL_DEPTH_TEST); // Enable z-depth
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clears the screen
glBindVertexArray(VAO); // Activate the Vertex Array Object before rendering and transforming them
//camera movement logic
if(currentKey == 'w')
cameraPosition += cameraSpeed * CameraForwardZ;
if(currentKey == 's')
cameraPosition -= cameraSpeed * CameraForwardZ;
if(currentKey == 'a')
cameraPosition -= glm::normalize(glm::cross(CameraForwardZ, CameraUpY)) * cameraSpeed;
if(currentKey == 'd')
cameraPosition += glm::normalize(glm::cross(CameraForwardZ, CameraUpY)) * cameraSpeed;
CameraForwardZ = front;
// Transforms the object
glm::mat4 model;
model = glm::translate(model, glm::vec3(0.0, 0.0f, 0.0f)); // Place the object at the center of the 7i,p9rA
model = glm::rotate(model, 45.0f, glm::vec3(1.0, 1.0f, 1.0f)); // Rotate the object 45 degrees on the XYZ
model = glm::scale(model, glm::vec3(1.0f, 1.0f, -1.0f)); // Increase the object size by a scale of 2
// Transforms the camera
glm::mat4 view;
view = glm::lookAt(cameraPosition, cameraPosition + CameraForwardZ, CameraUpY); //Moves the world 0.5 units on X and -5 units in Z
// Creates a perspective projection
glm::mat4 projection;
projection = glm::perspective(45.0f, (GLfloat)WindowWidth / (GLfloat)WindowHeight, 0.1f, 100.0f);
// Retrieves and passes transform matrices to the Shader program
GLint modelLoc = glGetUniformLocation(ShaderProgram, "model");
GLint viewLoc = glGetUniformLocation(ShaderProgram, "view");
GLint projLoc = glGetUniformLocation(ShaderProgram, "projection");
glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(projection));
glutPostRedisplay();
// Draws the triangles
glDrawArrays(GL_TRIANGLES,0, 36);
glBindVertexArray(0); // Deactivate the Vertex Array Object
glutSwapBuffers(); // Flips the the back buffer with the front buffer every frame. Similar to GL FLush
}
/*Creates the Shader program*/
void UCreateShader()
{
// Vertex shader
GLint vertexShader = glCreateShader(GL_VERTEX_SHADER); // Creates the Vertex Shader
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL); // Attaches the Vertex Shader to the source code
glCompileShader(vertexShader); // Compiles the Vertex Shader
// Fragment Shader
GLint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER); // Creates the Fragment Shader
glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);// Attaches the Fragment Shader to the source code
glCompileShader(fragmentShader); // Compiles the Fragment Shader
// Shader program
ShaderProgram = glCreateProgram(); // Creates the Shader program and returns an id
glAttachShader(ShaderProgram, vertexShader); // Attach Vertex Shader to the Shader program
glAttachShader(ShaderProgram, fragmentShader);; // Attach Fragment Shader to the Shader program
glLinkProgram(ShaderProgram); //Link Vertex and Fragment shader, to Shader program
// Delete the Vertex and Fragment shaders once linked
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
}
/*creates the buffer and array object*/
void UCreateBuffers()
{
//position and color data
GLfloat vertices[] = {
//vertex positions and colors
-0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 1.0f, 1.0f,
0.5f, -0.5f, -0.5f, 0.0f, 1.0f, 1.0f,
0.5f, -0.5f, 0.5f, 0.0f, 1.0f, 1.0f,
0.5f, -0.5f, 0.5f, 0.0f, 1.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 1.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 1.0f, 1.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 1.0f,
0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 1.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 1.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 1.0f,
-0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 1.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 1.0f,
};
//Generate buffer id,
glGenVertexArrays(1, &VAO);
glGenBuffers(1,&VBO);
// Activate the Vertex Array Object before binding and setting any VB0s and Vertex Attribute Pointers.
glBindVertexArray(VAO);
// Activate the VBO
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); //Copy vertices to VBO
// Set attribute pointer 0 to hold Position data
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0); // Enables vertex attribute
// Set attribute pointer 1 to hold Color data
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(1); // Enables vertex attribute
glBindVertexArray(0); // Deactivates the VAC, which is good practice
}
//implement the UKeyboard function
void UKeyboard(unsigned char key, GLint x, GLint y)
{
switch(key){
case 'w':
currentKey = key;
cout<<"You Pressed W"<<endl;
break;
case 's':
currentKey = key;
cout<<"You Pressed S"<<endl;
break;
case 'a':
currentKey = key;
cout<<"You Pressed A"<<endl;
break;
case 'd':
currentKey = key;
cout<<"You Pressed D"<<endl;
break;
default:
cout<<"Press a key!"<<endl;
}
}
//implement the UKeyReleased function
void UKeyReleased(unsigned char key, GLint x, GLint y)
{
cout<<"Key Released!"<<endl;
currentKey = '0';
}
//implement UMouseMove function
void UMouseMove(int x, int y)
{
if(mouseDetected)
{
lastMouseX = x;
lastMouseY = y;
mouseDetected = false;
}
//get the direction mouse was moved
mouseXOffset = x - lastMouseX;
mouseYOffset = lastMouseY - y;
//update new coordinates
lastMouseX = x;
lastMouseY = y;
//apply sensitivity
mouseXOffset *= sensitivity;
mouseYOffset *= sensitivity;
//accumulate yaw and pitch
yaw += mouseXOffset;
pitch += mouseYOffset;
//maintain 90 degree pitch
if (pitch > 89.0f)
pitch = 89.0f;
if (pitch > -89.0f)
pitch = -89.0f;
//convert mouse coordinates
front.x = cos(glm::radians(pitch)) * cos(glm::radians(yaw));
front.y = sin(glm::radians(pitch));
front.z = cos(glm::radians(pitch)) * sin(glm::radians(yaw));
}
解决方案
从沿正 z 轴平移的相机位置开始（例如 (0, 0, 10)）。front必须初始化：
glm::vec3 cameraPosition = glm::vec3(0.0f,0.0f,10.0f);
glm::vec3 CameraUpY = glm::vec3(0.0f,1.0f,0.0f);
glm::vec3 CameraForwardZ = glm::vec3(0.0f,0.0f,-1.0f);
glm::vec3 front = glm::vec3(0.0f,0.0f,-1.0f);
您必须初始化模型矩阵变量glm::mat4 model。
glm API 文档参考了OpenGL 着色语言规范 4.20。
5.4.2 向量和矩阵构造函数
如果向量构造函数有一个标量参数，则它用于将构造向量的所有组件初始化为该标量的值。如果矩阵构造函数只有一个标量参数，则它用于初始化矩阵对角线上的所有分量，其余分量初始化为 0.0。
这意味着，一个单位矩阵可以由单个参数 1.0 初始化：
glm::mat4 model(1.0f);
OpenGL数学中的角度单位是弧度而不是度数。( glm::perspective, glm::rotate):
// Transforms the object
glm::mat4 model(1.0f);
model = glm::translate(model, glm::vec3(0.0, 0.0f, 0.0f)); // Place the object at the center of the 7i,p9rA
model = glm::rotate(model, glm::radians(45.0f), glm::vec3(1.0, 1.0f, 1.0f)); // Rotate the object 45 degrees on the XYZ
model = glm::scale(model, glm::vec3(1.0f, 1.0f, -1.0f)); // Increase the object size by a scale of 2
// Transforms the camera
glm::mat4 view = glm::lookAt(cameraPosition, cameraPosition + CameraForwardZ, CameraUpY); //Moves the world 0.5 units on X and -5 units in Z
// Creates a perspective projection
glm::mat4 projection = glm::perspective(glm::radians(45.0f), (GLfloat)WindowWidth / (GLfloat)WindowHeight, 0.1f, 100.0f);
计算时有一些错误front。pitch < -89.0f而不是pitch > -89.0f. x 轴为sin(glm::radians(yaw))，z 轴为-cos(glm::radians(yaw))：
//maintain 90 degree pitch
if (pitch > 89.0f)
pitch = 89.0f;
if (pitch < -89.0f)
pitch = -89.0f;
//convert mouse coordinates
front.x = cos(glm::radians(pitch)) * sin(glm::radians(yaw));
front.y = sin(glm::radians(pitch));
front.z = cos(glm::radians(pitch)) * -cos(glm::radians(yaw));
此外，sensitivity接缝要牢固，我建议减少它（例如GLfloat sensitivity = 0.05f;）。
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