如何让实例化在我的 OpenGL 程序中工作？
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【中文标题】如何让实例化在我的 OpenGL 程序中工作？【英文标题】：How to get instancing to work in my OpenGL program? 【发布时间】：2020-06-18 04:31:00 【问题描述】：https://pastebin.com/Dyv5JBFd
我为我的立方体创建了一个顶点数组。我正在尝试创建 1000 个立方体形状的立方体。我相信我不明白何时生成和绑定 VAO 和 VBO。我不知道什么信息可以帮助解决这个问题。在 pastebin 中，我首先包含了着色器，然后是主代码。什么都没有显示，但它正在运行。
编辑：立方体在第 100 行
编辑 2：实例化代码从 160 开始
编辑 3：显示矩阵从 272 开始
编辑 4：绘制调用从 293 开始
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 2) in mat4 instanceMatrix;
uniform mat4 view;
uniform mat4 projection;
void main()
gl_Position = projection * view * instanceMatrix * vec4(aPos, 1.0f);
#include <glew.h>
#include <glfw3.h>
#include <iostream>
#include <glm.hpp>
#include <gtc/matrix_transform.hpp>
#include <gtc/type_ptr.hpp>
#include "Shaders/Functions/loadShader.h"
#include "Camera.h"
#include "Input/Input.h"
//Function used to resize the window appropriately.
void FrameBufferSizeCallback(GLFWwindow* window, int width, int height);
inline void Mouse(GLFWwindow* window, double xPos, double yPos);
//Global screen settings.
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;
//Global camera variables.
Camera camera(glm::vec3(0.0f, 0.0f, 3.0f));
//Global timing variables.
float deltaTime = 0.0f; //Time difference of current frame and last frame.
float lastTime = 0.0f; //Keeps track of the time of the last frame. Used to calculate deltaTime.
int main(void)
/* Initialize the library */
if (!glfwInit())
std::cout << "GLFW initialization failed." << std::endl;
return -1;
/* OpenGLtutorials.org tutorial */
//Triangle doesn't show if other 3 are uncommented
glfwWindowHint(GLFW_SAMPLES, 4); //4x antialiasing
//glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); //OpenGL 3.3
//glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
//glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); //We don't want the old OpenGL
//glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
/* OpenGLtutorials.org tutorial end */
GLFWwindow* window;
/* Create a windowed mode window and its OpenGL context */
window = glfwCreateWindow(1280, 1024, "Window of the Gods!", NULL, NULL);
if (!window)
glfwTerminate();
std::cout << "GLFW window creation failed." << std::endl;
return -1;
/* Make the window's context current */
glfwMakeContextCurrent(window);
//Added code
glfwSetFramebufferSizeCallback(window, FrameBufferSizeCallback);
glfwSetCursorPosCallback(window, Mouse);
//Tells GLFW to capture our mouse.
glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
//Check if GLEW is initialized
if (glewInit() != GLEW_OK)
std::cout << "GLEW failed to initialize." << std::endl;
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
//Compile and load shaders and store the program id
GLuint programID = LoadShaders("Shaders/Vertex/CameraShader.vert", "Shaders/Fragment/SimpleFragmentShader.frag");
//Prints the GLEW and openGL versions
std::cout << "Using GLEW version :" << glewGetString(GLEW_VERSION) << std::endl;
std::cout << "Using openGL version: " << glGetString(GL_VERSION) << std::endl;
/*
*******CUBE*******
An array of 3 vectors which represents 3 vertices; 6 to make a rectangle; Each segment represents a face of a cube, made of two triangles;
Looking at the face, the first vertex of each triangle is top left, triangle formed counter-clockwise; First vertex on top is (-0.5, 0.5, -0.5);
First vertex on bottom is (-0.5, -0.5, 0.5);
1 3
4
2
5 6
*/
static const GLfloat cubeVertexBuffer[] =
//Front
-0.5f, 0.5f, 0.5f,
0.5f, -0.5f, 0.5f,
0.5f, 0.5f, 0.5f,
-0.5f, 0.5f, 0.5f,
-0.5f, -0.5f, 0.5f,
0.5f, -0.5f, 0.5f,
//Right
0.5f, 0.5f, 0.5f,
0.5f, -0.5f, -0.5f,
0.5f, 0.5f, -0.5f,
0.5f, 0.5f, 0.5f,
0.5f, -0.5f, 0.5f,
0.5f, -0.5f, -0.5f,
//Back
0.5f, 0.5f, -0.5f,
-0.5f, -0.5f, -0.5f,
-0.5f, 0.5f, -0.5f,
0.5f, 0.5f, -0.5f,
0.5f, -0.5f, -0.5f,
-0.5f, -0.5f, -0.5f,
//Left
-0.5f, 0.5f, -0.5f,
-0.5f, -0.5f, 0.5f,
-0.5f, 0.5f, 0.5f,
-0.5f, 0.5f, -0.5f,
-0.5f, -0.5f, -0.5f,
-0.5f, -0.5f, 0.5f,
//Top
-0.5f, 0.5f, -0.5f,
0.5f, 0.5f, 0.5f,
0.5f, 0.5f, -0.5f,
-0.5f, 0.5f, -0.5f,
-0.5f, 0.5f, 0.5f,
0.5f, 0.5f, 0.5f,
//Bottom
-0.5f, -0.5f, 0.5f,
0.5f, -0.5f, -0.5f,
0.5f, -0.5f, 0.5f,
-0.5f, -0.5f, 0.5f,
-0.5f, -0.5f, -0.5f,
0.5f, -0.5f, -0.5f,
;
//World space position of our cube.
/*glm::vec3 cubePosition[] =
glm::vec3( 0.0f, 0.0f, 0.0f),
;*/
//INSTANCING TEST
//Need to do: make sure the coordinates right.
unsigned int cubeGridXCoord = 10;
unsigned int cubeGridYCoord = 10;
unsigned int cubeGridZCoord = 10;
float displacement = 4.0f;
unsigned int currentIndex = 0;
glm::mat4* modelMatrices;
modelMatrices = new glm::mat4[cubeGridXCoord * cubeGridYCoord * cubeGridZCoord];
for (unsigned int i = 0; i < cubeGridXCoord; i++)
for (unsigned int j = 0; j < cubeGridYCoord; j++)
for (unsigned int k = 0; k < cubeGridZCoord; k++)
glm::mat4 model = glm::mat4(1.0f);
model = glm::translate(model, glm::vec3((float)i / displacement, (float)j / displacement, (float)k / displacement));
model = glm::scale(model, glm::vec3(0.1f));
modelMatrices[currentIndex++] = model;
//INSTANCING TEST END
unsigned int VAO;
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
//Identify vertex buffer
GLuint vertexbuffer;
//Generate 1 buffer, put the resulting identifier in vertexbuffer
glGenBuffers(1, &vertexbuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
//Give the vertices to OpenGL
//glBufferData(GL_ARRAY_BUFFER, sizeof(cubeVertexBuffer), cubeVertexBuffer, GL_STATIC_DRAW);
glBufferData(GL_ARRAY_BUFFER, sizeof(cubeVertexBuffer), cubeVertexBuffer, GL_STATIC_DRAW);
//Added code end
//First attribute buffer : vertices
glEnableVertexAttribArray(0);
glVertexAttribPointer
(
0, //attribute 0. No reason 0, but must match layout in shader.
3, //size
GL_FLOAT, //type
GL_FALSE, //normalized?
0, //stride
(void*)0 //array buffer offset
);
glBindVertexArray(0);
unsigned int matricesBuffer;
glGenBuffers(1, &matricesBuffer);
glBindBuffer(GL_ARRAY_BUFFER, matricesBuffer);
glBufferData(GL_ARRAY_BUFFER, cubeGridXCoord * cubeGridYCoord * cubeGridZCoord * sizeof(glm::mat4), &modelMatrices[0], GL_STATIC_DRAW);
glBindVertexArray(VAO);
// vertex attributes
glEnableVertexAttribArray(2);
glVertexAttribPointer(2, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), (void*)0);
glEnableVertexAttribArray(3);
glVertexAttribPointer(3, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), (void*)(1 * sizeof(glm::vec4)));
glEnableVertexAttribArray(4);
glVertexAttribPointer(4, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), (void*)(2 * sizeof(glm::vec4)));
glEnableVertexAttribArray(5);
glVertexAttribPointer(5, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), (void*)(3 * sizeof(glm::vec4)));
glVertexAttribDivisor(2, 1);
glVertexAttribDivisor(3, 1);
glVertexAttribDivisor(4, 1);
glVertexAttribDivisor(5, 1);
glBindVertexArray(0);
double previousFPSTime = glfwGetTime();
int frameCount = 0;
/* Loop until the user closes the window */
while (!glfwWindowShouldClose(window))
//Get the time variables and display fps
float currentTime = glfwGetTime();
deltaTime = currentTime - lastTime;
lastTime= currentTime;
frameCount++;
if (currentTime - previousFPSTime >= 1.0f)
std::cout << "FPS: " << frameCount << "\r";
frameCount = 0;
previousFPSTime = currentTime;
//Input
ProcessInput(window, camera, deltaTime);
/* Render here */
glClearColor(0.0f, 0.0f, 0.5f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
//Added code
glUseProgram(programID);
//Pass the projection matrix to shader ( in this case could change every frame )
glm::mat4 projection = glm::perspective(glm::radians(45.0f), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
glUniformMatrix4fv(glGetUniformLocation(programID, "projection"), 1, GL_FALSE, &projection[0][0]);
//Camera/view transformation.
glm::mat4 view = camera.GetViewMatrix();
glUniformMatrix4fv(glGetUniformLocation(programID, "view"), 1, GL_FALSE, &view[0][0]);
//for (unsigned int i = 0; i < 1000; i++)
//
// //Calculate model matrix and initialize.
// glm::mat4 model = glm::mat4(1.0f);
// model = glm::translate(model, cubePosition[0] + glm::vec3(glm::cos(i)* 0.2f + (glm::cos(i)), i * 0.1f, glm::sin(i) * 0.2f + (glm::sin(i))));
// //model = glm::rotate(model, glm::radians(0.0f), glm::vec3(1.0f, 0.3f, 0.5f));
// model = glm::scale(model, glm::vec3(0.1f));
// glUniformMatrix4fv(glGetUniformLocation(programID, "model"), 1, GL_FALSE, &model[0][0]);
// //Draw the triangle
// glDrawArrays(GL_TRIANGLES, 0, 36); // Starting from vertex 0; 3 vertices = one triangle, 6 = one face, 36 = one cube;
//
glBindVertexArray(VAO);
glDrawElementsInstanced(GL_TRIANGLES, 36, GL_UNSIGNED_INT, 0, cubeGridXCoord * cubeGridYCoord * cubeGridZCoord);
glBindVertexArray(0);
//Added code end
/* Swap front and back buffers */
glfwSwapBuffers(window);
/* Poll for and process events */
glfwPollEvents();
glDisableVertexAttribArray(0);
glfwTerminate();
return 0;
【问题讨论】：
@Rabbid76 抱歉，我想这会有所帮助，我一直在敲击键盘。它正在运行，并会打开一个窗口，但没有显示任何立方体。 @rabbid76 我注释掉的代码可以迭代地渲染立方体。如果这有帮助的话。 那么情况是你注释掉了渲染立方体的代码，现在立方体没有渲染？ @Jamit 是的，因为我试图以不同的方式呈现它们。我使用了 1000 个绘图调用，而我想用一个来代替实例化。 @Jamit 是的，明天我会回来的，只是希望大师能发现一些明显的东西。谢谢 【参考方案1】：您的代码 sn-p 通过glDrawElementsInstanced() 绘制索引几何：
glDrawElementsInstanced(GL_TRIANGLES, 36, GL_UNSIGNED_INT, 0, cubeGridXCoord * cubeGridYCoord * cubeGridZCoord);
没有绑定索引缓冲区 (GL_ELEMENT_ARRAY_BUFFER)。
应使用glDrawArraysInstanced() 代替绘图元素，或者应添加索引几何的定义。
另一个可疑的时刻是绑定4个属性数组：
glVertexAttribPointer(2, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), (void*)0);
glVertexAttribPointer(3, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), (void*)(1 * sizeof(glm::vec4)));
glVertexAttribPointer(4, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), (void*)(2 * sizeof(glm::vec4)));
glVertexAttribPointer(5, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), (void*)(3 * sizeof(glm::vec4)));
虽然 GLSL 程序只定义了一个
layout (location = 2) in mat4 instanceMatrix;
我希望 GLSL 程序在这种情况下会定义 4 个vec4 顶点属性并在代码中构造mat4，但我之前没有处理过这个（也许你正在使用 OpenGL 规范接受的技巧）。
【讨论】：
glDrawElementsInstanced/glDrawArraysInstanced 是对的。无论如何，您必须为 mat4 类型的顶点着色器输入指定 4 个属性，这部分问题很好。
非常感谢你，我现在让他们展示了。这太棒了。现在我需要找出操纵单个立方体的最佳方法。再次感谢！
从 20 fps 的 10000 个立方体到 70 fps 的 125k，这太棒了。以上是关于如何让实例化在我的 OpenGL 程序中工作？的主要内容，如果未能解决你的问题，请参考以下文章
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