From a3e1bc1e0039ca4dae1a30693274e31fd123e670 Mon Sep 17 00:00:00 2001
From: iridiumR <i@iridium.cyou>
Date: Tue, 23 May 2023 01:21:52 +0800
Subject: [PATCH] feat(OpenGL): hello

---
 OpenGL/hello/src/main.cpp | 73 ++++++++++++++++++++++++++++-----------
 1 file changed, 52 insertions(+), 21 deletions(-)

diff --git a/OpenGL/hello/src/main.cpp b/OpenGL/hello/src/main.cpp
index 1d0aa71..cbd9400 100644
--- a/OpenGL/hello/src/main.cpp
+++ b/OpenGL/hello/src/main.cpp
@@ -3,25 +3,46 @@
 #include <iostream>
 
 // 三角形顶点
-float vertices[] = {-0.5f, -0.5f, 0.0f, 0.5f, -0.5f, 0.0f, 0.0f, 0.5f, 0.0f};
+float vertices[] = {
+    // 第一个三角形
+    0.4f, 0.4f, 0.0f,   // 右上角
+    0.4f, -0.4f, 0.0f,  // 右下角
+    -0.4f, -0.4f, 0.0f, // 左下角
+    -0.4f, 0.4f, 0.0f   // 左上角
+};
+
+// 索引
+unsigned int indices[] = {
+    0, 1, 3, // 第一个三角形
+    1, 2, 3  // 第二个三角形
+};
 
 // 顶点着色器源码
-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"
-    "}\0";
+const char *vertexShaderSource =R"(
+    #version 330 core
+    layout (location = 0) in vec3 aPos;
+    layout (location = 1) in vec3 aColor;
+
+    out vec3 color;
+
+    void main()
+    {
+        gl_Position = vec4(aPos, 1.0);
+        color = aColor;
+    }
+)";
 
 // 片段着色器源码
-const char *fragmentShaderSource =
-    "#version 330 core\n"
-    "out vec4 FragColor;\n"
-    "void main()\n"
-    "{\n"
-    "   FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
-    "}\n\0";
+const char *fragmentShaderSource = R"(
+    #version 330 core
+    in vec3 color;
+    out vec4 FragColor;
+
+    void main()
+    {
+        FragColor = vec4(color, 1.0);
+    }
+)";
 
 void framebuffer_size_callback(GLFWwindow *window, int width, int height);
 void processInput(GLFWwindow *window);
@@ -112,20 +133,24 @@ int main() {
   glDeleteShader(vertexShader);
   glDeleteShader(fragmentShader);
 
+
+  unsigned int VAO,VBO,EBO;
   // 创建顶点数组对象
-  unsigned int VAO;
   glGenVertexArrays(1, &VAO);
   glBindVertexArray(VAO);
 
   // 创建顶点缓冲对象
-  unsigned int VBO;
   glGenBuffers(1, &VBO);
-
-  // 将顶点数据复制到缓冲中
   glBindBuffer(GL_ARRAY_BUFFER, VBO);
   glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
 
-  // 设置顶点数据解析方式
+  // 创建索引缓冲对象
+  glGenBuffers(1, &EBO);
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
+  glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices,
+               GL_STATIC_DRAW);
+
+  // 设置顶点属性指针
   glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void *)0);
   glEnableVertexAttribArray(0);
 
@@ -141,7 +166,13 @@ int main() {
     // 绘制三角形, 激活程序
     glUseProgram(shaderProgram);
     glBindVertexArray(VAO);
-    glDrawArrays(GL_TRIANGLES, 0, 3);
+    //使用线框模式绘制
+    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+    // 设置线宽
+    glLineWidth(3.0f);
+    // 绘制
+    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+    glBindVertexArray(0);
 
     // 检查并调用事件，交换缓冲
     glfwSwapBuffers(window);