材质
如果我们想要在OpenGL中模拟多种类型的物体，我们必须为每个物体分别定义一个材质(Material)属性。
我们为每个冯氏光照模型的分量都定义一个颜色向量。
- ambient材质向量定义了在环境光照下这个物体反射得是什么颜色，通常这是和物体颜色相同的颜色。
- diffuse材质向量定义了在漫反射光照下物体的颜色。（和环境光照一样）漫反射颜色也要设置为我们需要的物体颜色。
- specular材质向量设置的是镜面光照对物体的颜色影响（或者甚至可能反射一个物体特定的镜面高光颜色）。
- shininess影响镜面高光的散射/半径。
但是，光源对环境光、漫反射和镜面光分量也具有着不同的强度。也需要分别设置。
code
#include "../env/glm/glm.hpp"
#include "../env/glm/gtc/matrix_transform.hpp"
#include "../env/glm/gtc/type_ptr.hpp"
#include <iostream>
#define STB_IMAGE_IMPLEMENTATION
#include "../env/std_image.h"
#include "../env/glad.h"
#include "../env/glfw3.h"
#include <fstream>
#include "../tools/shader.h"
#include "../tools/camera.h"
#define WIDTH 800
#define HEIGHT 600
GLFWwindow *initialize(int width, int height);
void framebuffer_size_callback(GLFWwindow *window, int width, int height);
void mouse_callback(GLFWwindow *window, double xpos, double ypos);
void scroll_callback(GLFWwindow *window, double xoffset, double yoffset);
void processInput(GLFWwindow *window);
Camera camera = Camera(glm::vec3(0.0f, 0.0f, 3.0f),
glm::vec3(0.0f, 0.0f, -1.0f),
glm::vec3(0.0f, 1.0f, 0.0f),
0.0f, 0.0f);
float cameraSpeed = 2.5f;
float lastTime;
float lastXPos;
float lastYPos;
bool firstMouse;
float fov = 45.0f;
int main()
{
GLFWwindow *window = initialize(WIDTH, HEIGHT);
float 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};
unsigned int myVBO;
glGenBuffers(1, &myVBO);
glBindBuffer(GL_ARRAY_BUFFER, myVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
GLuint objectVAO;
glGenVertexArrays(1, &objectVAO);
glBindVertexArray(objectVAO);
glBindBuffer(GL_ARRAY_BUFFER, myVBO);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)(3 * sizeof(float)));
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
GLuint lightVAO;
glGenVertexArrays(1, &lightVAO);
glBindVertexArray(lightVAO);
glBindBuffer(GL_ARRAY_BUFFER, myVBO);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)0);
glEnableVertexAttribArray(0);
glm::mat4 model, view, projection;
Shader lampShader("2.2-vertex.glsl", "1-lamp-fragment.glsl");
Shader lightShader("2.2-vertex.glsl", "3-fragment.glsl");
lastTime = glfwGetTime();
glEnable(GL_DEPTH_TEST);
while (!glfwWindowShouldClose(window))
{
model = glm::mat4(1.0f);
glm::vec3 lightPos = glm::vec3(1.2f, 1.0f, 2.0f);
model = glm::translate(model, lightPos);
model = glm::scale(model, glm::vec3(0.2f));
view = camera.lookAt();
projection = glm::perspective(glm::radians(fov), 1.0f * WIDTH / HEIGHT, 0.1f, 100.0f);
lampShader.use();
lampShader.setm4fv("model", GL_FALSE, glm::value_ptr(model));
lampShader.setm4fv("view", GL_FALSE, glm::value_ptr(view));
lampShader.setm4fv("projection", GL_FALSE, glm::value_ptr(projection));
glBindVertexArray(lightVAO);
glDrawArrays(GL_TRIANGLES, 0, 36);
model = glm::mat4(1.0f);
lightShader.use();
lightShader.setm4fv("model", GL_FALSE, glm::value_ptr(model));
lightShader.setm4fv("view", GL_FALSE, glm::value_ptr(view));
lightShader.setm4fv("projection", GL_FALSE, glm::value_ptr(projection));
glm::vec3 lightColor = glm::vec3(1.0f, 1.0f, 1.0f);
// glm::vec3 objectColor = glm::vec3(1.0f, 0.5f, 0.31f);
lightShader.setv3("lightColor", glm::value_ptr(lightColor));
// lightShader.setv3("objectColor", glm::value_ptr(objectColor));
glm::vec3 cameraPos = camera.getPosition();
lightShader.setv3("viewPos", glm::value_ptr(cameraPos));
lightShader.setv3("lightPos", glm::value_ptr(lightPos));
glm::vec3 ambient = glm::vec3(1.0f, 0.5f, 0.31f);
glm::vec3 diffuse = glm::vec3(1.0f, 0.5f, 0.31f);
glm::vec3 specular = glm::vec3(0.5f, 0.5f, 0.5f);
float shiness = 32;
lightShader.setv3("material.ambient", glm::value_ptr(ambient));
lightShader.setv3("material.diffuse", glm::value_ptr(diffuse));
lightShader.setv3("material.specular", glm::value_ptr(specular));
lightShader.setf("material.shiness", shiness);
ambient = glm::vec3(0.2f, 0.2f, 0.2f);
diffuse = glm::vec3(0.5f, 0.5f, 0.5f);
specular = glm::vec3(1.0f, 1.0f, 1.0f);
lightShader.setv3("light.ambient", glm::value_ptr(ambient));
lightShader.setv3("light.diffuse", glm::value_ptr(diffuse));
lightShader.setv3("light.specular", glm::value_ptr(specular));
glBindVertexArray(objectVAO);
glDrawArrays(GL_TRIANGLES, 0, 36);
processInput(window);
glfwSwapBuffers(window);
glfwPollEvents();
glClearColor(0.0, 0.0, 0.0, 0.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
}
glfwTerminate();
return 0;
}
void framebuffer_size_callback(GLFWwindow *window, int width, int height)
{
glViewport(0, 0, width, height);
}
void processInput(GLFWwindow *window)
{
float currentTime = glfwGetTime();
float delta = currentTime - lastTime;
lastTime = currentTime;
float distance = cameraSpeed * delta;
// 移动照相机位置
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
{
glfwSetWindowShouldClose(window, true);
}
else if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
{
camera.move(CameraMovement::FORWARD, distance);
}
else if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
{
camera.move(CameraMovement::BACKWARD, distance);
}
else if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
{
camera.move(CameraMovement::LEFT, distance);
}
else if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
{
camera.move(CameraMovement::RIGHT, distance);
}
else if (glfwGetKey(window, GLFW_KEY_E) == GLFW_PRESS)
{
camera.move(CameraMovement::DOWN, distance);
}
else if (glfwGetKey(window, GLFW_KEY_Q) == GLFW_PRESS)
{
camera.move(CameraMovement::UP, distance);
}
}
GLFWwindow *initialize(int width, int height)
{
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow *window = glfwCreateWindow(WIDTH, HEIGHT, "2", nullptr, nullptr);
if (!window)
{
exit(-1);
}
glfwMakeContextCurrent(window);
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
exit(-1);
}
glViewport(0, 0, width, height);
glfwSetWindowSizeCallback(window, framebuffer_size_callback);
// 光标初始位置
lastXPos = 400;
lastYPos = 300;
firstMouse = true;
glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
glfwSetCursorPosCallback(window, mouse_callback);
glfwSetScrollCallback(window, scroll_callback);
return window;
}
void mouse_callback(GLFWwindow *window, double xpos, double ypos)
{
if (firstMouse)
{
lastXPos = xpos;
lastYPos = ypos;
firstMouse = false;
}
float sensitivity = 0.05f;
float xOffset = (xpos - lastXPos) * sensitivity;
float yOffset = (lastYPos - ypos) * sensitivity;
lastXPos = xpos;
lastYPos = ypos;
camera.rotate(xOffset, yOffset);
}
void scroll_callback(GLFWwindow *window, double xoffset, double yoffset)
{
fov -= yoffset;
if (fov <= 1.0f)
{
fov = 1.0f;
}
if (fov >= 45.0f)
{
fov = 45.0f;
}
}
3-fragment.glsl
#version 330 core
struct Material{
vec3 ambient, diffuse, specular;
float shiness;
};
struct Light{
vec3 position, ambient, diffuse, specular;
};
in vec3 Normal;
in vec3 fragPos;
uniform vec3 lightColor;
uniform vec3 objectColor;
uniform vec3 lightPos;
uniform vec3 viewPos;
uniform Material material;
uniform Light light;
out vec4 FragColor;
void main() {
vec3 ambientStrength = material.ambient * light.ambient;
vec3 lightDir = normalize(lightPos - fragPos);
vec3 normal = normalize(Normal);
vec3 diffuseStrength = max(0.0f, dot(normal, lightDir)) * material.diffuse * light.diffuse;
vec3 viewDir = normalize(viewPos - fragPos);
vec3 reflectDir = reflect(-lightDir, normal);
vec3 specularStrength = pow(max(0.0f, dot(viewDir, reflectDir)), material.shiness) * material.specular * light.specular;
FragColor = vec4((ambientStrength + diffuseStrength + specularStrength)* lightColor, 1.0f);
}