1mb/s memory leak without a single new

Question

I've created a "ping pong" shader class which renders a shader between two textures. For some reason the program has a massive memory leak which I can't locate. I don't use a single new statement within the display function. The code looks like this:

Display func:

void display()
{
    r->Render();
    glutSwapBuffers();
}

Render:

void Effect2::Render()
{


    shader.Start(time);
    glBegin(GL_QUADS);
    {
        glTexCoord2f(0.0f, 0.0f);
        glVertex2f(-1.0f, -1.0f);

        glTexCoord2f(1.0f, 0.0f);
        glVertex2f(1.0f, -1.0f);

        glTexCoord2f(1.0f, 1.0f);
        glVertex2f(1.0f, 1.0f);

        glTexCoord2f(0.0f, 1.0f);
        glVertex2f(-1.0f, 1.0f);

    }

    glEnd();
    shader.End();

    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    glEnable(GL_TEXTURE_2D);
    shader.BindCurrentTexture();
    glBegin(GL_QUADS);
    {
        glTexCoord2f(0.0f, 0.0f);
        glVertex2f(-1.0f, -1.0f);

        glTexCoord2f(1.0f, 0.0f);
        glVertex2f(1.0f, -1.0f);

        glTexCoord2f(1.0f, 1.0f);
        glVertex2f(1.0f, 1.0f);

        glTexCoord2f(0.0f, 1.0f);
        glVertex2f(-1.0f, 1.0f);

    }
    glEnd();
    glDisable(GL_TEXTURE_2D);
    Renderer::Render();
}

shader start, end, bindtexture:

void PingPongShader::Start(float time)
{

    if(!began)
    {

        //buffer
        glGenFramebuffers(1, &frameBuffer);
        GLenum drawBuffers[1] = {GL_COLOR_ATTACHMENT0};
        glDrawBuffers(1, drawBuffers);

        glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer);
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, textures[current], 0);
        glEnable(GL_TEXTURE_2D);
        glBindTexture(GL_TEXTURE_2D, textures[abs(current-1)]);
        glUseProgram(shader);
        if(paramCallback != NULL)
            paramCallback(shader);
        //internal shader vars
        glUniform2f(screenSizeLoc, (float)width, (float)height);
        if(drawingRadius > 0)
        {
            glUniform1f(dr_radius, drawingRadius);
            glUniform4f(dr_color, drawingColor[0], drawingColor[1], drawingColor[2], drawingColor[3]);
            glUniform2f(dr_pos, drawingPos[0], drawingPos[1]);
        }
        else
        {
            glUniform1f(dr_radius, -1.0);
        }

        glUniform1f(timeLoc, time);
        began = true;

    }
    else
    {
        printf("Could not call Start(). Did you forget to call End() ?");
    }

}
void PingPongShader::End()
{
    if(began)
    {

        glUseProgram(0);
        glBindFramebuffer(GL_FRAMEBUFFER, 0);
        glDisable(GL_TEXTURE_2D);
        current = abs(current-1);
        began = false;


    }
    else
    {
        printf("Could not call End(). Did you forget to call Start() ?");
    }
}
void PingPongShader::BindCurrentTexture()
{
    glBindTexture(GL_TEXTURE_2D, textures[skip ? abs(current-1) : current]);
}

Except for the memory leak, the output is exactly what I expect.

Any ideas?

Answer 1

You're calling glGenFramebuffers in each Start(), thus allocating a new buffer object in each frame.

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Side note: 1 - current is more efficient (and I'd say more idiomatic) than abs(current - 1) for alternating between 0 and 1.