Resizing window using SDL and OpenGL

Question

Before writing this question, I have read the question: Handling window resizing using OpenGL and SDL. However that question does not solve my problem, since I am using SDL2 and not SDL1.2. But I do use OpenGL2. My complete source code is available at: http://dpaste.com/17BVBP6

I am writing a program that displays a white square in the window. However I am having trouble while handling window resize events.Here is my resize function:

void resize(int width,int height)
{
    if(height<=0)    height=1;

    glViewport(0,0,(GLsizei)width,(GLsizei)height);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60.0f,float(width)/float(height),1.0f,100.0f);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

My Main event loop:

while( !quit )
        {
            while( SDL_PollEvent( &e ) != 0 )
            {
                switch (e.type) {
                case SDL_QUIT:
                    quit=true;
                    break;
                case SDL_WINDOWEVENT_SIZE_CHANGED:
                    resize(e.window.data1,e.window.data2);
                    break;
                case SDL_KEYDOWN:
                    switch (e.key.keysym.sym) {
                    case SDLK_ESCAPE:
                        quit=true;
                        break;
                    default:
                        break;
                    }
                default:
                    break;
                }
            }

            render();

            update(gWindow);
        }

Here is my window when it is not resized:

Here is my window when it is resized:

What is the causing the problem here??

keltar keltar · Accepted Answer · 2018-03-18T07:36:41

SDL_WINDOWEVENT_SIZE_CHANGED is not an event type, it is variation of SDL_WINDOWEVENT. Your event checking should be like

switch(e.type) {
    case SDL_WINDOWEVENT:
        if(e.window.event == SDL_WINDOWEVENT_SIZE_CHANGED) {
            resize(e.window.data1,e.window.data2);
        }
        break;

Also remove your perspective projection setting - it is inconsistend with your draw, and you don't have perspective setup before resize.

Resizing window using SDL and OpenGL

1 Answers