问题描述
以下代码应在带有OpenGL兼容性配置文件的窗口上显示一个红色三角形,但除了空白的窗口核心配置文件外,我什么也看不到:
The following code should displays a red triangle on the window with OpenGL compatibility profile, but I can see nothing but a blank window core profile:
#include <GL/glew.h>
#include <GLFW/glfw3.h>
unsigned int shader_create(const char* src_vertex, const char* src_fragment) {
...
}
int main(void)
{
GLFWwindow* window;
/* Initialize the library */
if (!glfwInit()) return -1;
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR,3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR,3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
/* 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) return -1;
float coordinates[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, sizeof(coordinates), coordinates, GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, 0);
const char* vertex_shader = ... ;
const char* fragment_shader = ... ;
unsigned int shader = shader_create(vertex_shader, fragment_shader);
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;
}
顶点着色器:
#version 330 core
layout(location = 0) in vec4 position;
void main() {
gl_Position = position;
}
片段着色器:
#version 330 core
layout(location = 0) out vec4 color;
void main() {
color = vec4(1.0, 0.0, 0.0, 1.0);
}
当我不使用着色器时(不是一个好主意),我可以完美地看到默认白色的三角形(至少在我的GPU上).同样,如果使用兼容性配置文件而不是核心配置文件,它也可以工作.
When I use no shaders (not a good idea), I can perfectly see the triangle in the default white color (at least on my GPU). Also if use compatibility profile instead of core profile, it works.
我试图同时使用C和C ++代码进行编译,但都无法显示三角形.
I tried to compile as both C and C++ code but both fails to show the triangle.
我在这里做错了什么?着色器的源代码不正确吗?
What am I doing wrong here? Is the source code for shader incorrect?
推荐答案
使用核心配置文件时 OpenGL上下文,您必须生成并命名为顶点数组对象,因为默认的顶点数组对象(0)"无效.
When you use a core profile OpenGL Context, you've to generate and named Vertex Array Object, because the default Vertex Array Object (0) is not valid.
切换到兼容性配置文件:
Either switch to a compatibility profile:
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_COMPAT_PROFILE);
或为顶点规范创建一个命名的VAO:
or create a named VAO for the vertex specification:
GLuint vao;
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, 0);
这篇关于为什么在带有OpenGL核心配置文件的窗口上看不到我的红色三角形?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!