SDL2 不创建三角形

Question

我试图制作一个三角形，但是当我编译和运行程序时它不会呈现。

代码如下：

#include <iostream>
#include <gl/GL.h>
#include <SDL.h>
#include <SDL_opengl.h>

const int windowWidth = 1280, windowHeight = 720;

int main(int argc, char* argv[])
{
    // Create window //
    SDL_Window* window = SDL_CreateWindow("OpenGL Test", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, windowWidth, windowHeight, SDL_WINDOW_OPENGL);

    if (window == NULL)
    {
        return EXIT_FAILURE;
    }

    SDL_Event windowEvent;

    // OpenGL context //
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);

    // Main loop //
    while (true)
    {
        if (SDL_PollEvent(&windowEvent))
        {
            if (windowEvent.type == SDL_QUIT)
            {
                break;
            }
        }
        // Draw //
        glClearColor(0.f, 0.f, 0.f, 1.f);
        glClear(GL_COLOR_BUFFER_BIT);

        glBegin(GL_TRIANGLES);
            glColor3f(1.f, 0.f, 0.f);
            glVertex2f(0, 0.5);
            glColor3f(0.f, 1.f, 0.f);
            glVertex2f(-0.5, -0.5);
            glColor3f(0.f, 0.f, 1.f);
            glVertex2f(0.5, -0.5);
        glEnd();

        glFlush();

        SDL_GL_SwapWindow(window);
    }

    SDL_DestroyWindow(window);
    SDL_Quit();

    return EXIT_SUCCESS;
}

Answer 1

多个问题：

在SDL_CreateWindow().

SDL_GL_SetAttribute()

在尝试调用任何 GL 函数之前，使用 SDL_GL_CreateContext() 创建 GL 上下文。

如果您最终使用 SDL_GL_CONTEXT_PROFILE_CORE，您将需要完全 re-write 其余的 GL 代码，以不使用所有那些已删除的功能，例如 glBegin()/glVertex()/glColor()/glEnd().

总计：

// g++ main.cpp `pkg-config --cflags --libs sdl2 gl` #include <SDL.h> #include <SDL_opengl.h> int main(int argc, char* argv[]) { SDL_Window* window = SDL_CreateWindow("OpenGL Test", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, SDL_WINDOW_OPENGL); if (window == NULL) { return EXIT_FAILURE; } SDL_GLContext ctx = SDL_GL_CreateContext( window ); // Main loop // while (true) { SDL_Event windowEvent; if (SDL_PollEvent(&windowEvent)) { if (windowEvent.type == SDL_QUIT) { break; } } // Draw // glClearColor(0.f, 0.f, 0.f, 1.f); glClear(GL_COLOR_BUFFER_BIT); glBegin(GL_TRIANGLES); glColor3f(1.f, 0.f, 0.f); glVertex2f(0, 0.5); glColor3f(0.f, 1.f, 0.f); glVertex2f(-0.5, -0.5); glColor3f(0.f, 0.f, 1.f); glVertex2f(0.5, -0.5); glEnd(); SDL_GL_SwapWindow(window); } SDL_GL_DeleteContext( ctx ); SDL_DestroyWindow(window); SDL_Quit(); return EXIT_SUCCESS; }

SDL2 不创建三角形

SDL2 not creating triangle

c++

opengl

opengl-3

sdl-2