使用C++库GLEW在openGl中绘制一个红色三角形[关闭]
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【中文标题】使用C++库GLEW在openGl中绘制一个红色三角形[关闭]【英文标题】:to draw a red triangle in openGl using c++ library GLEW [closed] 【发布时间】:2018-03-11 10:00:33 【问题描述】:我正在尝试使用 GLEW 在 OpenGL 中绘制一个红色三角形。首先,我在屏幕中心画了一个三角形。这是正确绘制的。然后,我尝试使用着色器来获得一个红色三角形。但是,我无法获得红色三角形,因为我的着色器编译失败。什么可能是错的?
#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)
std::cout << "failed to compile shader" << std::endl;
return id;
static 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);
glDetachShader(program,vs);
glDetachShader(program,fs);
glDeleteShader(vs);
glDeleteShader(fs);
return program;
int main(void)
GLFWwindow* window;
/* Initialize the library */
if (!glfwInit())
return -1;
/* Create a windowed mode window and its OpenGL context */
window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
if (!window)
glfwTerminate();
return -1;
/* Make the window's context current */
glfwMakeContextCurrent(window);
if (glewInit() != GLEW_OK)
std::cout << "error..!!" << std::endl;
float positions[6] =
-0.5f,-0.5f,
0.5f, -0.5f,
0.0f, 0.5f
;
unsigned int buffer;
glGenBuffers(1, &buffer);
glBindBuffer(GL_ARRAY_BUFFER, buffer);
glBufferData(GL_ARRAY_BUFFER, 6 * sizeof(float),positions,GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, 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))
/* Render here */
glClear(GL_COLOR_BUFFER_BIT);
glDrawArrays(GL_TRIANGLES,0,3);
/* Swap front and back buffers */
glfwSwapBuffers(window);
/* Poll for and process events */
glfwPollEvents();
glfwTerminate();
return 0;
【问题讨论】:
打印着色器信息日志怎么样? khronos.org/opengl/wiki/… 【参考方案1】:着色器编译失败,因为着色器在片段中color=vec4(1.0,0.0,0.0,1.0)
后面缺少分号。
如果你打印着色器信息日志,那么你可以很容易地发现这样的问题:
glCompileShader(id);
GLint status;
glGetShaderiv( id, GL_COMPILE_STATUS, &status );
if ( status == GL_FALSE )
GLint maxLen;
glGetShaderiv( id, GL_INFO_LOG_LENGTH, &maxLen );
std::vector< char >log( maxLen );
GLsizei len;
glGetShaderInfoLog( id, maxLen, &len, log.data() );
std::cout << "compile error:" << std::endl << log.data() << std::endl;
另外,我推荐使用Raw string literals:
std::string fragmentShader = R"(
#version 330 core
layout(location=0) out vec4 color;
void main()
color=vec4(1.0, 0.0, 0.0, 1.0);
)";
【讨论】:
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