你好，三角形的课后练习题
文章目录
- 你好，三角形的课后练习题
- 一、创建相同的两个三角形，但对它们的数据使用不同的VAO和VBO
一、创建相同的两个三角形，但对它们的数据使用不同的VAO和VBO
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow* window);
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;
const char* vertexShaderSource = "#version 330 core\n"
"layout (location = 0) in vec3 aPos; \n"
"void main()\n"
"{\n"
" gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
"}\n";
const char* fragmentShaderSource = "#version 330 core\n"
"out vec4 FragColor;\n"
"void main()\n"
"{\n"
" FragColor = vec4(1.0, 0.5f, 0.2f, 1.0f);\n"
"}\n";
int main()
{
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 << "创建窗口失败" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
std::cout << "GLAD初始化失败" << std::endl;
return -1;
}
int success;
char infoLog[512];
unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
glCompileShader(vertexShader);
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
std::cout << infoLog << std::endl;
}
unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
glCompileShader(fragmentShader);
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
std::cout << infoLog << std::endl;
}
unsigned int shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
glGetShaderiv(shaderProgram, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(shaderProgram, 512, NULL, infoLog);
std::cout << infoLog << std::endl;
}
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
float vertices0[] = {
-0.9f, -0.5f, 0.0f, // left
-0.0f, -0.5f, 0.0f, // right
-0.45f, 0.5f, 0.0f, // top
};
float vertices1[] = {
0.9f, 0.5f, 0.0f, // left
0.0f, 0.5f, 0.0f, // right
0.45f, -0.5f, 0.0f, // top
};
unsigned int VBOs[2], VAOs[2];
glGenBuffers(2, VBOs);
glGenVertexArrays(2, VAOs);
glBindVertexArray(VAOs[0]);
//复制顶点数组到缓冲中供OpenGL使用
glBindBuffer(GL_ARRAY_BUFFER, VBOs[0]);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices0), vertices0, GL_STATIC_DRAW);
//如何解析顶点数据
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glBindVertexArray(VAOs[1]);
glBindBuffer(GL_ARRAY_BUFFER, VBOs[1]);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices1), vertices1, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (void*)0);
glEnableVertexAttribArray(0);
//不知道这两段代码的作用
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
while (!glfwWindowShouldClose(window))
{
processInput(window);
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(shaderProgram);
glBindVertexArray(VAOs[0]);
glDrawArrays(GL_TRIANGLES, 0, 3);
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
glBindVertexArray(VAOs[1]);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwSwapBuffers(window);
glfwPollEvents();
}
glDeleteVertexArrays(2, VAOs);
glDeleteBuffers(2, VBOs);
glDeleteProgram(shaderProgram);
glfwTerminate();
return 0;
}
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
glViewport(0, 0, width, height);
}
void processInput(GLFWwindow* window)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
}
二、创建两个着色器程序，第二个程序使用一个不同的片段着色器，输出黄色；再次绘制这两个三角形，让其中一个输出为黄色
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow* window);
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;
const char* vertexShaderSource = "#version 330 core\n"
"layout (location = 0) in vec3 aPos; \n"
"void main()\n"
"{\n"
" gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
"}\n";
const char* fragmentShader1Source = "#version 330 core\n"
"out vec4 FragColor;\n"
"void main()\n"
"{\n"
" FragColor = vec4(1.0, 0.5f, 0.2f, 1.0f);\n"
"}\n\0";
const char* fragmentShader2Source = "#version 330 core\n"
"out vec4 FragColor;\n"
"void main()\n"
"{\n"
" FragColor = vec4(1.0, 1.0f, 1.0f, 1.0f);\n"
"}\n\0";
int main()
{
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 << "创建窗口失败" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
std::cout << "GLAD初始化失败" << std::endl;
return -1;
}
unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
glCompileShader(vertexShader);
unsigned int fragmentShaderOrange = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShaderOrange, 1, &fragmentShader1Source, NULL);
glCompileShader(fragmentShaderOrange);
unsigned int shaderProgramOrange = glCreateProgram();
glAttachShader(shaderProgramOrange, vertexShader);
glAttachShader(shaderProgramOrange, fragmentShaderOrange);
glLinkProgram(shaderProgramOrange);
unsigned int fragmentShaderYellow = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShaderYellow, 1, &fragmentShader2Source, NULL);
glCompileShader(fragmentShaderYellow);
unsigned int shaderProgramYellow = glCreateProgram();
glAttachShader(shaderProgramYellow, vertexShader);
glAttachShader(shaderProgramYellow, fragmentShaderYellow);
glLinkProgram(shaderProgramYellow);
float firstTriangle[] = {
-0.9f, -0.5f, 0.0f, // left
-0.0f, -0.5f, 0.0f, // right
-0.45f, 0.5f, 0.0f, // top
};
float secondTriangle[] = {
0.0f, -0.5f, 0.0f, // left
0.9f, -0.5f, 0.0f, // right
0.45f, 0.5f, 0.0f // top
};
unsigned int VBOs[2], VAOs[2];
glGenVertexArrays(2, VAOs);
glGenBuffers(2, VBOs);
glBindVertexArray(VAOs[0]);
//复制顶点数组到缓冲中供OpenGL使用
glBindBuffer(GL_ARRAY_BUFFER, VBOs[0]);
glBufferData(GL_ARRAY_BUFFER, sizeof(firstTriangle), firstTriangle, GL_STATIC_DRAW);
//如何解析顶点数据
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glBindVertexArray(VAOs[1]);
glBindBuffer(GL_ARRAY_BUFFER, VBOs[1]);
glBufferData(GL_ARRAY_BUFFER, sizeof(secondTriangle), secondTriangle, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (void*)0);
glEnableVertexAttribArray(0);
//不知道这两段代码的作用
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
while (!glfwWindowShouldClose(window))
{
processInput(window);
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(shaderProgramOrange);
glBindVertexArray(VAOs[0]);
glDrawArrays(GL_TRIANGLES, 0, 3);
glUseProgram(shaderProgramYellow);
glBindVertexArray(VAOs[1]);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwSwapBuffers(window);
glfwPollEvents();
}
glDeleteVertexArrays(2, VAOs);
glDeleteBuffers(2, VBOs);
glDeleteProgram(shaderProgramOrange);
glDeleteProgram(shaderProgramYellow);
glfwTerminate();
return 0;
}
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
glViewport(0, 0, width, height);
}
void processInput(GLFWwindow* window)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
}
