此程序在窗口上渲染一个红色三角形，该程序在Win上运行，但在Linux上却出现黑屏。在编译/链接阶段没有错误。我正在使用NVIDIA的专有驱动程序。可能是什么问题？
这是我的代码：
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
static unsigned int CompileShader(unsigned int type, const std::string &source) {
unsigned int id = glCreateShader(type);
const char *src = source.c_str();
glShaderSource(id, 1, &src, nullptr);
glCompileShader(id);
int result;
glGetShaderiv(id, GL_COMPILE_STATUS, &result);
if (result == GL_FALSE) {
int length;
glGetShaderiv(id, GL_INFO_LOG_LENGTH, &length);
char *message = (char*)alloca(length * sizeof(char));
glGetShaderInfoLog(id, length, &length, message);
std::cout << "Failed to compile " << (type == GL_VERTEX_SHADER ? "vertex" : "fragment") << "shader" << std::endl;
std::cout << message << std::endl;
glDeleteShader(id);
return 0;
}
return id;
}
static unsigned int CreateShader(const std::string &vertexShader, const std::string &fragmentShader) {
unsigned int program = glCreateProgram();
unsigned int vs = CompileShader(GL_VERTEX_SHADER, vertexShader);
unsigned int fs = CompileShader(GL_FRAGMENT_SHADER, fragmentShader);
glAttachShader(program, vs);
glAttachShader(program, fs);
glLinkProgram(program);
glValidateProgram(program);
glDeleteShader(vs);
glDeleteShader(fs);
return program;
}
int main(void)
{
GLFWwindow *window;
/* Initialize the library */
if (!glfwInit()) {
std::cout << "Error initialising glfw3!" << std::endl;
return -1;
}
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
if (!window)
{
std::cout << "Error initialising a window!" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
if (glewInit() != GLEW_OK) {
std::cout << "Error initialising GLEW!" << std::endl;
return -1;
}
std::cout << glGetString(GL_VERSION) << std::endl;
float positions[6] = {
-0.5f, -0.5f,
0.0f, 0.5f,
0.5f, -0.5f
};
unsigned int buffer;
glGenBuffers(1, &buffer);
glBindBuffer(GL_ARRAY_BUFFER, buffer);
glBufferData(GL_ARRAY_BUFFER, 6 * sizeof(float), positions, GL_STATIC_DRAW);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), 0);
glEnableVertexAttribArray(0);
std::string vertexShader =
"#version 330 core\n"
"\n"
"layout(location = 0) in vec4 position;\n"
"\n"
"void main()\n"
"{\n"
" gl_Position = position;\n"
"}\n";
std::string fragmentShader =
"#version 330 core\n"
"\n"
"layout(location = 0) out vec4 color;\n"
"\n"
"void main()\n"
"{\n"
" color = vec4(1.0, 0.0, 0.0, 1.0);\n"
"}\n";
unsigned int shader = CreateShader(vertexShader, fragmentShader);
glUseProgram(shader);
/* Loop until the user closes the window */
while (!glfwWindowShouldClose(window))
{
glClear(GL_COLOR_BUFFER_BIT);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwSwapBuffers(window);
glfwPollEvents();
}
glDeleteProgram(shader);
glfwTerminate();
return 0;
}
编译代码：
g++ -std=c++17 main.cpp -Wall -lGL -lGLU -lGLEW -lglfw3 -lX11 -lXxf86vm -lXrandr -lpthread -lXi -ldl -lXinerama -lXcursor -o main
答案 0 :(得分：3)
在渲染任何内容之前，核心上下文需要绑定Vertex Array Object (VAO)。
您可以在程序的开头创建一个VAO，如果您不想花哨的话可以将其绑定：
GLuint vao = 0;
glCreateVertexArrays( 1, &vao );
glBindVertexArray( vao );
...
glDrawArrays(GL_TRIANGLES, 0, 3);
一起：
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
static unsigned int CompileShader(unsigned int type, const std::string &source) {
unsigned int id = glCreateShader(type);
const char *src = source.c_str();
glShaderSource(id, 1, &src, nullptr);
glCompileShader(id);
int result;
glGetShaderiv(id, GL_COMPILE_STATUS, &result);
if (result == GL_FALSE) {
int length;
glGetShaderiv(id, GL_INFO_LOG_LENGTH, &length);
char *message = (char*)alloca(length * sizeof(char));
glGetShaderInfoLog(id, length, &length, message);
std::cout << "Failed to compile " << (type == GL_VERTEX_SHADER ? "vertex" : "fragment") << "shader" << std::endl;
std::cout << message << std::endl;
glDeleteShader(id);
return 0;
}
return id;
}
static unsigned int CreateShader(const std::string &vertexShader, const std::string &fragmentShader) {
unsigned int program = glCreateProgram();
unsigned int vs = CompileShader(GL_VERTEX_SHADER, vertexShader);
unsigned int fs = CompileShader(GL_FRAGMENT_SHADER, fragmentShader);
glAttachShader(program, vs);
glAttachShader(program, fs);
glLinkProgram(program);
glValidateProgram(program);
glDeleteShader(vs);
glDeleteShader(fs);
return program;
}
int main(void)
{
GLFWwindow *window;
/* Initialize the library */
if (!glfwInit()) {
std::cout << "Error initialising glfw3!" << std::endl;
return -1;
}
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
if (!window)
{
std::cout << "Error initialising a window!" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
if (glewInit() != GLEW_OK) {
std::cout << "Error initialising GLEW!" << std::endl;
return -1;
}
std::cout << glGetString(GL_VERSION) << std::endl;
float positions[6] = {
-0.5f, -0.5f,
0.0f, 0.5f,
0.5f, -0.5f
};
GLuint vao = 0;
glCreateVertexArrays( 1, &vao );
glBindVertexArray( vao );
unsigned int buffer;
glGenBuffers(1, &buffer);
glBindBuffer(GL_ARRAY_BUFFER, buffer);
glBufferData(GL_ARRAY_BUFFER, 6 * sizeof(float), positions, GL_STATIC_DRAW);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), 0);
glEnableVertexAttribArray(0);
std::string vertexShader =
"#version 330 core\n"
"\n"
"layout(location = 0) in vec4 position;\n"
"\n"
"void main()\n"
"{\n"
" gl_Position = position;\n"
"}\n";
std::string fragmentShader =
"#version 330 core\n"
"\n"
"layout(location = 0) out vec4 color;\n"
"\n"
"void main()\n"
"{\n"
" color = vec4(1.0, 0.0, 0.0, 1.0);\n"
"}\n";
unsigned int shader = CreateShader(vertexShader, fragmentShader);
glUseProgram(shader);
/* Loop until the user closes the window */
while (!glfwWindowShouldClose(window))
{
glClear(GL_COLOR_BUFFER_BIT);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwSwapBuffers(window);
glfwPollEvents();
}
glDeleteProgram(shader);
glfwTerminate();
return 0;
}