我一直在学习教程here来学习OpenGL，但是我的代码并没有按照应有的方式发挥作用。我已经达到this点，了解基本照明。我的代码工作，显示阴影立方体;但是，当我尝试更改模型矩阵时，它仍然显示阴影，好像立方体位于原点。
为了确保它不仅仅是我，我复制了教程提供的代码（主要是）并添加了一行：
model = glm::translate(model, glm::vec3( 3.0, -1.0, 1.0));
......并且立方体移动了，但阴影保持不变！为什么呢？
因为代码中可能存在一些我不能正确理解的东西：这里是代码和着色器。 （同样，它主要不是我的。） 代码：
#include <string>
#include <iostream>
#include <cmath>
#define GLEW_STATIC
#include <GL/glew.h>
#include <SOIL/SOIL.h>
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <glm/gtx/projection.hpp>
#include "Shader.h"
#include "camera.h"
// 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
const GLuint WIDTH = 800, HEIGHT = 600;
// Camera
Camera camera(glm::vec3(0.0f, 0.0f, 3.0f));
GLfloat lastX = WIDTH / 2.0;
GLfloat lastY = HEIGHT / 2.0;
bool keys[1024];
// Light attributes
glm::vec3 lightPos(1.2f, 1.0f, 2.0f);
// Deltatime
GLfloat deltaTime = 0.0f; // Time between current frame and last frame
GLfloat lastFrame = 0.0f; // Time of last frame
// The MAIN function, from here we start the application and run the game loop
int main()
{
// Init GLFW
glfwInit();
// Set all the required options for GLFW
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);
// Create a GLFWwindow object that we can use for GLFW's functions
GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "LearnOpenGL", nullptr, nullptr);
glfwMakeContextCurrent(window);
// Set the required callback functions
glfwSetKeyCallback(window, key_callback);
glfwSetCursorPosCallback(window, mouse_callback);
glfwSetScrollCallback(window, scroll_callback);
// GLFW Options
glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
// Set this to true so GLEW knows to use a modern approach to retrieving function pointers and extensions
glewExperimental = GL_TRUE;
// Initialize GLEW to setup the OpenGL Function pointers
glewInit();
// Define the viewport dimensions
glViewport(0, 0, WIDTH, HEIGHT);
// OpenGL options
glEnable(GL_DEPTH_TEST);
// Build and compile our shader program
Shader* lightingShader = new Shader("lit_vertex_shader", "lit_fragment_shader");
Shader* lampShader = new Shader("lamp_vertex_shader", "lamp_fragment_shader");
// Set up vertex data (and buffer(s)) and attribute pointers
GLfloat vertices[] = {
-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, 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, 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, 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, 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
};
// First, set the container's VAO (and VBO)
GLuint VBO, containerVAO;
glGenVertexArrays(1, &containerVAO);
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindVertexArray(containerVAO);
// Position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
// Normal attribute
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(1);
glBindVertexArray(0);
// Then, we set the light's VAO (VBO stays the same. After all, the vertices are the same for the light object (also a 3D cube))
GLuint lightVAO;
glGenVertexArrays(1, &lightVAO);
glBindVertexArray(lightVAO);
// We only need to bind to the VBO (to link it with glVertexAttribPointer), no need to fill it; the VBO's data already contains all we need.
glBindBuffer(GL_ARRAY_BUFFER, VBO);
// Set the vertex attributes (only position data for the lamp))
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)0); // Note that we skip over the normal vectors
glEnableVertexAttribArray(0);
glBindVertexArray(0);
// Game loop
while (!glfwWindowShouldClose(window))
{
// Calculate deltatime of current frame
GLfloat currentFrame = glfwGetTime();
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
// Check if any events have been activiated (key pressed, mouse moved etc.) and call corresponding response functions
glfwPollEvents();
do_movement();
// Clear the colorbuffer
glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Use cooresponding shader when setting uniforms/drawing objects
lightingShader->Use();
GLint objectColorLoc = glGetUniformLocation(lightingShader->getProgram(), "objectColor");
GLint lightColorLoc = glGetUniformLocation(lightingShader->getProgram(), "lightColor");
GLint lightPosLoc = glGetUniformLocation(lightingShader->getProgram(), "lightPos");
glUniform3f(objectColorLoc, 1.0f, 0.5f, 0.31f);
glUniform3f(lightColorLoc, 1.0f, 1.0f, 1.0f);
glUniform3f(lightPosLoc, lightPos.x, lightPos.y, lightPos.z);
// Create camera transformations
glm::mat4 view;
view = camera.GetViewMatrix();
glm::mat4 projection = glm::perspective(camera.Zoom, (GLfloat)WIDTH / (GLfloat)HEIGHT, 0.1f, 100.0f);
// Get the uniform locations
GLint modelLoc = glGetUniformLocation(lightingShader->getProgram(), "model");
GLint viewLoc = glGetUniformLocation(lightingShader->getProgram(), "view");
GLint projLoc = glGetUniformLocation(lightingShader->getProgram(), "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));
// Draw the container (using container's vertex attributes)
glm::mat4 model;
//barring a few bits and pieces, following is the only changed line from the tutorial (I think)
model = glm::translate(model, glm::vec3( 3.0, -1.0, 1.0));
glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
glBindVertexArray(containerVAO);
glDrawArrays(GL_TRIANGLES, 0, 36);
glBindVertexArray(0);
// Also draw the lamp object, again binding the appropriate shader
lampShader->Use();
// Get location objects for the matrices on the lamp shader (these could be different on a different shader)
modelLoc = glGetUniformLocation(lampShader->getProgram(), "model");
viewLoc = glGetUniformLocation(lampShader->getProgram(), "view");
projLoc = glGetUniformLocation(lampShader->getProgram(), "projection");
// Set matrices
glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(projection));
model = glm::mat4();
model = glm::translate(model, lightPos);
model = glm::scale(model, glm::vec3(0.2f)); // Make it a smaller cube
glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
// Draw the light object (using light's vertex attributes)
glBindVertexArray(lightVAO);
glDrawArrays(GL_TRIANGLES, 0, 36);
glBindVertexArray(0);
// Swap the screen buffers
glfwSwapBuffers(window);
}
// Terminate GLFW, clearing any resources allocated by GLFW.
glfwTerminate();
return 0;
}
// Is called whenever a key is pressed/released via GLFW
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
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 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);
if(keys[GLFW_KEY_SPACE]) {
if(keys[GLFW_KEY_LEFT_SHIFT] or keys[GLFW_KEY_RIGHT_SHIFT]) {
camera.ProcessKeyboard(DOWN, deltaTime);
} else {
camera.ProcessKeyboard(UP, deltaTime);
}
}
}
bool firstMouse = true;
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);
}
顶点着色器：
#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
out vec3 Normal;
out vec3 FragPos;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
gl_Position = projection * view * model * vec4(position, 1.0f);
vec3 fragPos = vec3(model*vec4(position, 1.0f));
Normal = mat3(transpose(inverse(model)))*normal;
}
Fragment Shader：
#version 330 core
in vec3 Normal;
in vec3 FragPos;
out vec4 color;
uniform vec3 objectColor;
uniform vec3 lightColor;
uniform vec3 lightPos;
void main()
{
vec3 norm = normalize(Normal);
vec3 lightDir = normalize(lightPos - FragPos);
float diff = max(dot(norm, lightDir), 0.0);
vec3 diffuse = diff * lightColor;
float ambi = 0.05;
vec3 ambient = ambi * lightColor;
color = vec4((diffuse + ambient) * objectColor, 1.0);
}
答案 0 :(得分：0)
我想了一会儿，但一直犹豫要回答，因为它可能对其他人没有帮助。花了几个小时（！），但现在是。 （请注意，我已经更正了上面评论中提到的拼写错误; FragPos现在已正确大写。）
#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
out vec3 Normal;
out vec3 FragPos;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
gl_Position = projection * view * model * vec4(position, 1.0f);
vec3 FragPos = vec3(model*vec4(position, 1.0f));
Normal = mat3(transpose(inverse(model)))*normal;
}
看错了什么？没有？
...是的，它重新声明了FragPos作为它自己的局部变量并且没有传递任何东西。至少，我是这么认为的。在任何情况下，将vec3 FragPos = ...更改为FragPos = ...都会修复它。所有其他“修复”似乎只是起作用，因为他们没有足够的动作来表明FragPos总是为0。
无论如何，感谢dbandstra的帮助。