OpenGL 程序不显示三角形
OpenGL program doesn't show a triangle
我正在学习 C++ 中的 OpenGL 教程,但出于某种原因,完全相同的代码对我不起作用。
它应该显示一个三角形,但没有显示 anything.Just 空白屏幕。
这是代码:
#include<iostream>
#define GLEW_STATIC
#include"GL/glew.h"
#include"GLFW/glfw3.h"
static unsigned int compileShader(unsigned int type, const std::string& shader)
{
unsigned int id = glCreateShader(type);
const char* src = shader.c_str();
glShaderSource(id, 1, &src, NULL);
glCompileShader(id);
int result;
glGetShaderiv(id, GL_COMPILE_STATUS, &result);
if (!result) {
char log[512];
glGetShaderInfoLog(id, 512, NULL, log);
std::cout << "Compiling shader error:\n" << log << std::endl;
}
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);
int result;
glGetProgramiv(program, GL_LINK_STATUS, &result);
if (!result) {
char log[512];
glGetProgramInfoLog(program, 512, NULL, log);
std::cout << "linking shader error:\n" << log << std::endl;
}
glValidateProgram(program);
glDeleteShader(vs);
glDeleteShader(fs);
return program;
}
void keyCallBack(GLFWwindow* window, int key, int scancode, int action, int mode)
{
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
glfwSetWindowShouldClose(window, GL_TRUE);
}
int main()
{
int width = 0, height = 0;
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
GLFWwindow* window = glfwCreateWindow(500, 500, "Test", nullptr, nullptr);
glfwMakeContextCurrent(window);
glewExperimental = GL_TRUE;
glewInit();
glfwGetFramebufferSize(window, &width, &height);
glViewport(0, 0, width, height);
glfwSetKeyCallback(window, keyCallBack);
float triangle[] = {
-0.5f, -0.5f,
0.0f, 0.5f,
0.5f, -0.5f
};
GLuint buffer = 0;
glGenBuffers(1, &buffer);
glBindBuffer(GL_ARRAY_BUFFER, buffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(triangle), triangle, GL_STATIC_DRAW);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, 0);
glEnableVertexAttribArray(0);
std::string vertexShader = "#version 330 core\n"
"layout (location = 0) in vec4 position;\n"
"void main()\n"
"{\n"
"gl_Position = position;\n"
"}\n";
std::string fragmentShader = "#version 330 core\n"
"out vec4 color;\n"
"void main()\n"
"{\n"
"color = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
"}\n";
unsigned int program = createShader(vertexShader, fragmentShader);
glUseProgram(program);
while(!glfwWindowShouldClose(window)) {
glfwPollEvents();
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwSwapBuffers(window);
}
glfwTerminate();
return 0;
}
我真的不明白为什么working.The三角形的位置看起来不正确。glVertexAttribPointer
也看起来correct.I在编译和链接中找不到任何错误着色器及其来源..
编译和链接它们时我也得到零错误..
问题是由 GLFW_OPENGL_CORE_PROFILE
引起的。如果您使用核心配置文件 OpenGL Context, then you have to use a named Vertex Array Object,因为默认的 VAO (0) 无效。
要么使用兼容性配置文件:
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_COMPAT_PROFILE);
或者在指定顶点属性数据数组之前创建一个VAO:
GLuint VAO;
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, 0);
glEnableVertexAttribArray(0);
我正在学习 C++ 中的 OpenGL 教程,但出于某种原因,完全相同的代码对我不起作用。 它应该显示一个三角形,但没有显示 anything.Just 空白屏幕。 这是代码:
#include<iostream>
#define GLEW_STATIC
#include"GL/glew.h"
#include"GLFW/glfw3.h"
static unsigned int compileShader(unsigned int type, const std::string& shader)
{
unsigned int id = glCreateShader(type);
const char* src = shader.c_str();
glShaderSource(id, 1, &src, NULL);
glCompileShader(id);
int result;
glGetShaderiv(id, GL_COMPILE_STATUS, &result);
if (!result) {
char log[512];
glGetShaderInfoLog(id, 512, NULL, log);
std::cout << "Compiling shader error:\n" << log << std::endl;
}
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);
int result;
glGetProgramiv(program, GL_LINK_STATUS, &result);
if (!result) {
char log[512];
glGetProgramInfoLog(program, 512, NULL, log);
std::cout << "linking shader error:\n" << log << std::endl;
}
glValidateProgram(program);
glDeleteShader(vs);
glDeleteShader(fs);
return program;
}
void keyCallBack(GLFWwindow* window, int key, int scancode, int action, int mode)
{
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
glfwSetWindowShouldClose(window, GL_TRUE);
}
int main()
{
int width = 0, height = 0;
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
GLFWwindow* window = glfwCreateWindow(500, 500, "Test", nullptr, nullptr);
glfwMakeContextCurrent(window);
glewExperimental = GL_TRUE;
glewInit();
glfwGetFramebufferSize(window, &width, &height);
glViewport(0, 0, width, height);
glfwSetKeyCallback(window, keyCallBack);
float triangle[] = {
-0.5f, -0.5f,
0.0f, 0.5f,
0.5f, -0.5f
};
GLuint buffer = 0;
glGenBuffers(1, &buffer);
glBindBuffer(GL_ARRAY_BUFFER, buffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(triangle), triangle, GL_STATIC_DRAW);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, 0);
glEnableVertexAttribArray(0);
std::string vertexShader = "#version 330 core\n"
"layout (location = 0) in vec4 position;\n"
"void main()\n"
"{\n"
"gl_Position = position;\n"
"}\n";
std::string fragmentShader = "#version 330 core\n"
"out vec4 color;\n"
"void main()\n"
"{\n"
"color = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
"}\n";
unsigned int program = createShader(vertexShader, fragmentShader);
glUseProgram(program);
while(!glfwWindowShouldClose(window)) {
glfwPollEvents();
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwSwapBuffers(window);
}
glfwTerminate();
return 0;
}
我真的不明白为什么working.The三角形的位置看起来不正确。glVertexAttribPointer
也看起来correct.I在编译和链接中找不到任何错误着色器及其来源..
编译和链接它们时我也得到零错误..
问题是由 GLFW_OPENGL_CORE_PROFILE
引起的。如果您使用核心配置文件 OpenGL Context, then you have to use a named Vertex Array Object,因为默认的 VAO (0) 无效。
要么使用兼容性配置文件:
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_COMPAT_PROFILE);
或者在指定顶点属性数据数组之前创建一个VAO:
GLuint VAO;
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, 0);
glEnableVertexAttribArray(0);