Eu tenho um jogo sdl / opengl em que estou trabalhando por diversão. Eu recebo um fps decente em média, mas o movimento é realmente instável porque o SDL_GL_SwapBuffers () aleatoriamente demora muito para processar. Com texturas carregadas e escritas no buffer, às vezes, vai levar mais de 100ms! Eu recortei muito do meu código para tentar descobrir se era algo errado, mas não tive muita sorte. Quando eu executo esse programa básico, ele ainda bloqueia até 70ms, às vezes.

A Principal:

// Don't forget to link to opengl32, glu32, SDL_image.lib

// includes
#include <stdio.h>

// SDL
#include <cstdlib>
#include <SDL/SDL.h>

// Video
#include "videoengine.h"

int main(int argc, char *argv[])
{
    // begin SDL
    if ( SDL_Init(SDL_INIT_VIDEO) != 0 )
    {
        printf("Unable to initialize SDL: %s\n", SDL_GetError());
    }

    // begin video class
    VideoEngine videoEngine;

    // BEGIN MAIN LOOP
    bool done = false;
    while (!done)
    {
        int loopStart = SDL_GetTicks();

        printf("STARTING SWAP BUFFER : %d\n", SDL_GetTicks() - loopStart);
        SDL_GL_SwapBuffers();


        int total = SDL_GetTicks() - loopStart;
        if (total > 6)
            printf("END LOOP  : %d ------------------------------------------------------------>\n", total);
        else
             printf("END LOOP  : %d\n", total);

    }
    // END MAIN LOOP

    return 0;
}

Meu construtor "VideoEngine":

    VideoEngine::VideoEngine()
{
    UNIT = 16;
    SCREEN_X = 320;
    SCREEN_Y = 240;
    SCALE = 1;


    // Begin Initalization

        SDL_Surface *screen;

        SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );  // [!] SDL_GL_SetAttributes must be done BEFORE SDL_SetVideoMode

        screen = SDL_SetVideoMode( SCALE*SCREEN_X, SCALE*SCREEN_Y, 16, SDL_OPENGL );  // Set screen to the window with opengl
        if ( !screen )  // make sure the window was created
        {
            printf("Unable to set video mode: %s\n", SDL_GetError());
        }

        // set opengl state
        opengl_init();

    // End Initalization

}

void VideoEngine::opengl_init()
{
    // Set the OpenGL state after creating the context with SDL_SetVideoMode

        //glClearColor( 0, 0, 0, 0 );                             // sets screen buffer to black
        //glClearDepth(1.0f);                                     // Tells OpenGL what value to reset the depth buffer when it is cleared
        glViewport( 0, 0, SCALE*SCREEN_X, SCALE*SCREEN_Y );     // sets the viewport to the default resolution (SCREEN_X x SCREEN_Y) multiplied by SCALE. (x,y,w,h)
        glMatrixMode( GL_PROJECTION );                          // Applies subsequent matrix operations to the projection matrix stack.
        glLoadIdentity();                                       // Replaces the current matrix with the identity matrix
        glOrtho( 0, SCALE*SCREEN_X, SCALE*SCREEN_Y, 0, -1, 1 ); //describes a transformation that produces a parallel projection
        glMatrixMode( GL_MODELVIEW );                           // Applies subsequent matrix operations to the projection matrix stack.
        glEnable(GL_TEXTURE_2D);                                // Need this to display a texture
        glLoadIdentity();                                       // Replaces the current matrix with the identity matrix
        glEnable(GL_BLEND);                                     // Enable blending for transparency
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);      // Specifies pixel arithmetic
        //glDisable( GL_LIGHTING );                               // Disable lighting
        //glDisable( GL_DITHER );                                 // Disable dithering
        //glDisable( GL_DEPTH_TEST );                             // Disable depth testing

        //Check for error
        GLenum error = glGetError();
        if( error != GL_NO_ERROR )
        {
         printf( "Error initializing OpenGL! %s\n", gluErrorString( error ) );
        }

    return;
}

Estou começando a pensar que possivelmente tenho um problema de hardware? Eu nunca tive esse problema com um jogo embora.