我正努力让一个立方体在opengl中渲染。当我将已计算的MVP传递给顶点着色器时，它工作正常，但是当我传入模型时，查看和投影然后在顶点着色器中进行计算，它不会显示立方体。当我将顶点着色器的统一类型更改为mat4而不是vec4时，我也得到错误1282。
Main.cpp的
#include <iostream>
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <glm/glm.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtx/transform.hpp>
#include <fstream>
#include <stdlib.h>
#include <vector>
GLuint getShader(const char* shaderName, GLenum shaderType) {
std::cout << "Making shader " << shaderName << std::endl;
/* Read file */
std::cout << "Reading shader file" << std::endl;
std::ifstream shaderFile;
shaderFile.open(shaderName, std::ios_base::in);
if (!shaderFile) {
std::cout << shaderName << " not found" << std::endl;
return 0;
}
std::string line;
std::string shaderData;
while (std::getline(shaderFile, line)) {
shaderData += line + "\n";
}
shaderFile.close();
/* Create shader */
std::cout << "Compiling shader" << std::endl;
GLuint shader = glCreateShader(shaderType);
if (shader == 0) {
std::cout << "Failed to create shader for " << shaderName << std::endl;
return 0;
}
const char *shaderStr = shaderData.c_str();
glShaderSource(shader, 1, &shaderStr, nullptr);
glCompileShader(shader);
/* Check compile status */
GLint status;
glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
if (status != GL_TRUE) {
GLint logLength;
glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &logLength);
GLchar *infoLog = new GLchar[logLength + 1];
glGetShaderInfoLog(shader, logLength, nullptr, infoLog);
std::cout << shaderName << " failed to compile: " << infoLog << std::endl;
return 0;
}
GLenum error = glGetError();
if(error != GL_NO_ERROR) {
std::cout << "Failed making shader program, error " << error << ": " << glewGetErrorString(error) << std::endl;
return 0;
}
return shader;
}
int end(const char* message) {
glfwTerminate();
if(message != nullptr) {
std::cout << message << std::endl;
system("PAUSE");
}
return -1;
}
struct Shader {
const char* file;
GLenum type;
Shader(const char* file, GLenum type) {
this->type = type;
this->file = file;
}
};
GLuint getShader(Shader& shader) {
return getShader(shader.file, shader.type);
}
GLuint getShaderProgram(std::initializer_list<Shader> shaders, std::initializer_list<const char*> binds) {
/* Create the shader program */
GLuint shaderProgram = glCreateProgram();
GLenum error = glGetError();
if (shaderProgram == 0) {
std::cout << "Failed to create shader program" << std::endl;
return 0;
}
else if (glIsProgram(shaderProgram) != GL_TRUE) {
std::cout << "Failed to create shader program" << std::endl;
return 0;
}
else if(error != GL_NO_ERROR) {
std::cout << "Failed creating shader program, error " << error << ": " << glewGetErrorString(error) << std::endl;
return 0;
}
/* Compile & attach the shaders */
for(Shader shader : shaders) {
GLuint glShader = getShader(shader);
if (glShader == 0) {
std::cout << "Failed to load shader " << shader.file << std::endl;
return 0;
}
std::cout << "Attaching shader " << shader.file << std::endl;
glAttachShader(shaderProgram, glShader);
glDeleteShader(glShader);
error = glGetError();
if(error != GL_NO_ERROR) {
std::cout << "Failed attaching shader, error " << error << ": " << glewGetErrorString(error) << std::endl;
return 0;
}
}
/* Bind */
for(const char* bind : binds) {
std::cout << "Binding data location " << bind << std::endl;
glBindFragDataLocation(shaderProgram, 0, bind);
error = glGetError();
if(error != GL_NO_ERROR) {
std::cout << "Failed binding data location, error " << error << ": " << glewGetErrorString(error) << std::endl;
return 0;
}
}
/* Link to opengl */
glLinkProgram(shaderProgram);
error = glGetError();
if(error != GL_NO_ERROR) {
std::cout << "Failed linking shader program, error " << error << ": " << glewGetErrorString(error) << std::endl;
return 0;
}
return shaderProgram;
}
int main() {
/* Initial checks */
if (!glfwInit()) {
return end("Failed to startup GLFW");
}
int major = 3;
int minor = 3;
int rev = 0;
glfwGetVersion(&major, &minor, &rev);
/* Create the window */
GLFWwindow *window = glfwCreateWindow(500, 500, "3D world prototyping", nullptr, nullptr);
if (!window) {
return end("Failed to create window.");
}
glfwMakeContextCurrent(window); //make the window active
/* Startup GLEW */
glewExperimental = GL_TRUE;
if (glewInit() != GLEW_OK) {
return end("Failed to startup GLEW");
}
/* Start OpenGL constants */
glEnable(GL_DEPTH_TEST);
glEnableClientState(GL_VERTEX_ARRAY);
glViewport(0, 0, 800, 600);
/* Support for multiple shaders without the need to switch attributes */
GLuint vertexArray;
glGenVertexArrays(1, &vertexArray);
glBindVertexArray(vertexArray);
/* Shape vectors */
GLfloat verticies[] = {//X, Y, Z
-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,
-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,
-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,
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,
-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,
-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
};
GLuint shaderProgram = getShaderProgram({
Shader("vertexShader.glsl", GL_VERTEX_SHADER),
Shader("fragmentShader.glsl", GL_FRAGMENT_SHADER)
}, {
"outcolor"
});
if(shaderProgram == 0) {
return end("");
}
/* Load verticies into memory */
GLuint vertexBuffer;
glGenBuffers(1, &vertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(verticies), verticies, GL_STATIC_DRAW);
/* Getting uniform ids */
glUseProgram(shaderProgram);
// GLint mvpId = glGetUniformLocation(shaderProgram, "mvp");
GLint projectionId = glGetUniformLocation(shaderProgram, "projection");
GLint modelId = glGetUniformLocation(shaderProgram, "model");
GLint viewId = glGetUniformLocation(shaderProgram, "view");
GLenum error = glGetError();
if(error != GL_NO_ERROR) {
std::cout << "Uniform error " << error << ": " << glewGetErrorString(error) << std::endl;
return end("");
}
// else if(mvpId == -1) {
// return end("MVP ID failed to load");
// }
GLint positionAttribute = glGetAttribLocation(shaderProgram, "position");
if(positionAttribute == -1) {
std::cout << "Error: position attribute failed to load" << std::endl;
return end("");
}
/* Positioning */
//FOV, Screen ratio, display range short, display range long
glm::mat4 projection = glm::perspective(glm::radians(45.0f), 800.0f / 600.0f, 1.0f, 10.0f);
glm::mat4 model = glm::mat4(1.0f);
glm::mat4 mvp;
glm::vec3 camera = glm::vec3(0.0f, 0.0f, 3.0f);
glm::vec3 cameraLookingAt = glm::vec3(0.0f, 0.0f, 0.0f);
glm::vec3 cameraPitch = glm::vec3(0.0f, 1.0f, 0.0f);
float moveSpeed = 0.1f;
/* Rendering and logic */
while (!glfwWindowShouldClose(window)) {
/* Shutdown logic */
if (glfwGetKey(window, GLFW_KEY_ESCAPE)) {
break;
}
/* Clear */
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glClearColor(0.2f, 0.2f, 0.2f, 1.0f);
/* Logic */
/* Keypresses */
glfwPollEvents();
if(glfwGetKey(window, GLFW_KEY_W)) {
camera.z -= moveSpeed;
cameraLookingAt.z -= moveSpeed;
}
else if(glfwGetKey(window, GLFW_KEY_S)) {
camera.z += moveSpeed;
cameraLookingAt.z += moveSpeed;
}
if(glfwGetKey(window, GLFW_KEY_A)) {
camera.x -= moveSpeed;
cameraLookingAt.x -= moveSpeed;
}
else if(glfwGetKey(window, GLFW_KEY_D)) {
camera.x += moveSpeed;
cameraLookingAt.x += moveSpeed;
}
if(glfwGetKey(window, GLFW_KEY_Z)) {
camera.y += moveSpeed;
cameraLookingAt.y += moveSpeed;
}
else if(glfwGetKey(window, GLFW_KEY_X)) {
camera.y -= moveSpeed;
cameraLookingAt.y -= moveSpeed;
}
if(glfwGetKey(window, GLFW_KEY_UP)) {
cameraLookingAt.y += moveSpeed;
}
else if(glfwGetKey(window, GLFW_KEY_DOWN)) {
cameraLookingAt.y -= moveSpeed;
}
if(glfwGetKey(window, GLFW_KEY_LEFT)) {
cameraLookingAt.x -= moveSpeed;
cameraLookingAt.z -= moveSpeed;
}
else if(glfwGetKey(window, GLFW_KEY_RIGHT)) {
cameraLookingAt.x += moveSpeed;
cameraLookingAt.z += moveSpeed;
}
/* Update position */
mvp = projection * glm::lookAt(
camera,
cameraLookingAt,
cameraPitch
) * model;
glm::mat4 view = glm::lookAt(
camera,
cameraLookingAt,
cameraPitch
);
/* Draw */
glUseProgram(shaderProgram);
/* Update the position */
// glUniformMatrix4fv(mvpId, 1, GL_FALSE, &mvp[0][0]);
glUniform4fv(viewId, 1, glm::value_ptr(view));
glUniform4fv(modelId, 1, glm::value_ptr(model));
glUniform4fv(projectionId, 1, glm::value_ptr(projection));
/* Redraw the position using the verticies */
glEnableVertexAttribArray(positionAttribute);
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
glVertexAttribPointer(positionAttribute, 3, GL_FLOAT, GL_FALSE, 0, (void*)0); //because not just XYZ need to tell opengl the size of the stride
/* Draw the triangles */
glDrawArrays(GL_TRIANGLES, 0, 36);
glDisableVertexAttribArray(positionAttribute);
glfwSwapBuffers(window);
/* Realtime error checking */
error = glGetError();
if(error != GL_NO_ERROR) {
std::cout << "Error " << error << ": " << glewGetErrorString(error) << std::endl;
}
}
glfwDestroyWindow(window);
glDeleteProgram(shaderProgram);
glDeleteBuffers(1, &vertexBuffer);
glDeleteVertexArrays(1, &vertexArray);
return end(nullptr);
}
顶点着色器：
#version 330
uniform mat4 projection; /* view port / perspective */
uniform mat4 model; /* object */
uniform mat4 view; /* camera */
in vec3 position;
void main() {
gl_Position = projection * view * model * vec4(position, 1.0);
}
答案 0 :(得分：2)
您需要在调用glVertexAttribPointer时指定一个步幅，因为您的顶点未打包（您有位置和颜色数据交错）：
glVertexAttribPointer(positionAttribute, 3, GL_FLOAT, GL_FALSE, sizeof(GLfloat) * 6, 0);
答案 1 :(得分：1)
我修好了！
我要做的第一件事就是添加我的缓冲区绑定和属性指向while循环，我猜你每次调用useProgram时都要告诉opengl。
第二件事是我需要调用glUniformMatrix4fv，如果我想将我的值传递给mat4（他们需要的是，而不是vec4）。