submitTextureTime.cpp

// g++ submitTextureTime.cpp -o submitTextureTime $(pkg-config --cflags --libs gl sdl2) -lopenvr_api

#define GL_GLEXT_PROTOTYPES 1
#define GL3_PROTOTYPES 1
#include <GL/gl.h>

#include <chrono>
#include <iostream>
#include <SDL2/SDL.h>
#include <openvr.h>

#include <unistd.h>
#define Sleep(x) usleep((x)*1000)

using namespace vr;
void check_error(int line, EVRInitError error) { if (error != 0) printf("%d: error %s\n", line, VR_GetVRInitErrorAsSymbol(error)); }

int main(int argc, char **argv)
{
    SDL_Window *window = SDL_CreateWindow("SDL2/OpenGL Demo", 0, 0, 640, 480, SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE);
    SDL_GLContext glcontext = SDL_GL_CreateContext(window);
    SDL_GL_SetSwapInterval(0);


    EVRInitError error;
    VR_Init(&error, vr::VRApplication_Overlay);
    check_error(__LINE__, error);
    VROverlayHandle_t handle;
    VROverlay()->CreateOverlay ("textoverlay", "testoverlay", &handle);
    VROverlay()->SetOverlayWidthInMeters(handle, 0.1);
    VROverlay()->ShowOverlay(handle);


    uint32_t *fakeImage = (uint32_t*) malloc(sizeof(uint32_t) * 4096 * 4096 * 4);

    int loops = 10;

    for (int createNewTextures = 0; createNewTextures <= 1; createNewTextures++) {
        GLuint texture;
        if (!createNewTextures)
            glGenTextures(1, &texture);

        double totalSubmitDuration = 0;
        for (int i = 0; i < loops; i++) {
            const int width = 32;
            const int height = 32;
            glClearColor(i / (float)loops, 0, 0, 1);
            glClear(GL_COLOR_BUFFER_BIT);

            if (createNewTextures) {
                glGenTextures(1, &texture);
                glBindTexture(GL_TEXTURE_2D, texture);
            }

            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, (GLvoid*)fakeImage);

            Texture_t tex;
            tex.handle = (void*)(uintptr_t) texture;
            tex.eColorSpace = ColorSpace_Linear;
            tex.eType = TextureType_OpenGL;


            auto t_start = std::chrono::high_resolution_clock::now();
            VROverlay()->SetOverlayTexture(handle, &tex);
            auto t_end = std::chrono::high_resolution_clock::now();
            double submitDuration = std::chrono::duration<double, std::milli>(t_end-t_start).count();
            totalSubmitDuration += submitDuration;
            std::cout << "Submit time: " << submitDuration << "ms" << std::endl;


            if (createNewTextures)
                glDeleteTextures(1, &texture);

            SDL_GL_SwapWindow(window);

            Sleep(90./1); // doesn't matter that it's not actually 90 fps
        }

        if (!createNewTextures)
            glDeleteTextures(1, &texture);

        std::cout << "Avg texture submit time " << (createNewTextures ? "when creating new GL textures every time" : "when reusing GL textures") << " : " << totalSubmitDuration / (float)loops << std::endl;
    }

    free (fakeImage);
    SDL_GL_DeleteContext(glcontext);
}