path: root/src/capture/xcomposite_cuda.c

#include "../../include/capture/xcomposite_cuda.h"
#include "../../include/cuda.h"
#include "../../include/window_texture.h"
#include "../../include/utils.h"
#include <libavutil/hwcontext.h>
#include <libavutil/hwcontext_cuda.h>
#include <libavutil/frame.h>
#include <libavcodec/avcodec.h>

typedef struct {
    gsr_capture_xcomposite_cuda_params params;
    Display *dpy;
    XEvent xev;

    bool should_stop;
    bool stop_is_error;
    bool window_resized;
    bool created_hw_frame;
    bool follow_focused_initialized;
    double window_resize_timer;

    vec2i window_size;

    unsigned int target_texture_id;
    vec2i texture_size;
    Window window;
    WindowTexture window_texture;
    Atom net_active_window_atom;

    CUgraphicsResource cuda_graphics_resource;
    CUarray mapped_array;

    gsr_cuda cuda;
} gsr_capture_xcomposite_cuda;

static int max_int(int a, int b) {
    return a > b ? a : b;
}

static int min_int(int a, int b) {
    return a < b ? a : b;
}

static Window get_focused_window(Display *display, Atom net_active_window_atom) {
    Atom type;
    int format = 0;
    unsigned long num_items = 0;
    unsigned long bytes_after = 0;
    unsigned char *properties = NULL;
    if(XGetWindowProperty(display, DefaultRootWindow(display), net_active_window_atom, 0, 1024, False, AnyPropertyType, &type, &format, &num_items, &bytes_after, &properties) == Success && properties) {
        Window focused_window = *(unsigned long*)properties;
        XFree(properties);
        return focused_window;
    }
    return None;
}

static void gsr_capture_xcomposite_cuda_stop(gsr_capture *cap, AVCodecContext *video_codec_context);

static bool cuda_register_opengl_texture(gsr_capture_xcomposite_cuda *cap_xcomp) {
    CUresult res;
    CUcontext old_ctx;
    res = cap_xcomp->cuda.cuCtxPushCurrent_v2(cap_xcomp->cuda.cu_ctx);
    // TODO: Use cuGraphicsEGLRegisterImage instead with the window egl image (dont use window_texture).
    // That removes the need for an extra texture and texture copy
    res = cap_xcomp->cuda.cuGraphicsGLRegisterImage(
        &cap_xcomp->cuda_graphics_resource, cap_xcomp->target_texture_id, GL_TEXTURE_2D,
        CU_GRAPHICS_REGISTER_FLAGS_READ_ONLY);
    if (res != CUDA_SUCCESS) {
        const char *err_str = "unknown";
        cap_xcomp->cuda.cuGetErrorString(res, &err_str);
        fprintf(stderr,
                "Error: cuGraphicsGLRegisterImage failed, error %s, texture "
                "id: %u\n",
                err_str, cap_xcomp->target_texture_id);
        res = cap_xcomp->cuda.cuCtxPopCurrent_v2(&old_ctx);
        return false;
    }

    res = cap_xcomp->cuda.cuGraphicsResourceSetMapFlags(cap_xcomp->cuda_graphics_resource, CU_GRAPHICS_MAP_RESOURCE_FLAGS_READ_ONLY);
    res = cap_xcomp->cuda.cuGraphicsMapResources(1, &cap_xcomp->cuda_graphics_resource, 0);

    res = cap_xcomp->cuda.cuGraphicsSubResourceGetMappedArray(&cap_xcomp->mapped_array, cap_xcomp->cuda_graphics_resource, 0, 0);
    res = cap_xcomp->cuda.cuCtxPopCurrent_v2(&old_ctx);
    return true;
}

static bool cuda_create_codec_context(gsr_capture_xcomposite_cuda *cap_xcomp, AVCodecContext *video_codec_context) {
    CUcontext old_ctx;
    cap_xcomp->cuda.cuCtxPushCurrent_v2(cap_xcomp->cuda.cu_ctx);

    AVBufferRef *device_ctx = av_hwdevice_ctx_alloc(AV_HWDEVICE_TYPE_CUDA);
    if(!device_ctx) {
        fprintf(stderr, "Error: Failed to create hardware device context\n");
        cap_xcomp->cuda.cuCtxPopCurrent_v2(&old_ctx);
        return false;
    }

    AVHWDeviceContext *hw_device_context = (AVHWDeviceContext*)device_ctx->data;
    AVCUDADeviceContext *cuda_device_context = (AVCUDADeviceContext*)hw_device_context->hwctx;
    cuda_device_context->cuda_ctx = cap_xcomp->cuda.cu_ctx;
    if(av_hwdevice_ctx_init(device_ctx) < 0) {
        fprintf(stderr, "Error: Failed to create hardware device context\n");
        av_buffer_unref(&device_ctx);
        cap_xcomp->cuda.cuCtxPopCurrent_v2(&old_ctx);
        return false;
    }

    AVBufferRef *frame_context = av_hwframe_ctx_alloc(device_ctx);
    if(!frame_context) {
        fprintf(stderr, "Error: Failed to create hwframe context\n");
        av_buffer_unref(&device_ctx);
        cap_xcomp->cuda.cuCtxPopCurrent_v2(&old_ctx);
        return false;
    }

    AVHWFramesContext *hw_frame_context =
        (AVHWFramesContext *)frame_context->data;
    hw_frame_context->width = video_codec_context->width;
    hw_frame_context->height = video_codec_context->height;
    hw_frame_context->sw_format = AV_PIX_FMT_BGR0;
    hw_frame_context->format = video_codec_context->pix_fmt;
    hw_frame_context->device_ref = device_ctx;
    hw_frame_context->device_ctx = (AVHWDeviceContext*)device_ctx->data;

    hw_frame_context->initial_pool_size = 1;

    if (av_hwframe_ctx_init(frame_context) < 0) {
        fprintf(stderr, "Error: Failed to initialize hardware frame context "
                        "(note: ffmpeg version needs to be > 4.0)\n");
        av_buffer_unref(&device_ctx);
        //av_buffer_unref(&frame_context);
        cap_xcomp->cuda.cuCtxPopCurrent_v2(&old_ctx);
        return false;
    }

    video_codec_context->hw_device_ctx = av_buffer_ref(device_ctx);
    video_codec_context->hw_frames_ctx = av_buffer_ref(frame_context);
    return true;
}

static unsigned int gl_create_texture(gsr_capture_xcomposite_cuda *cap_xcomp, int width, int height) {
    unsigned int texture_id = 0;
    cap_xcomp->params.egl->glGenTextures(1, &texture_id);
    cap_xcomp->params.egl->glBindTexture(GL_TEXTURE_2D, texture_id);
    cap_xcomp->params.egl->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);

    cap_xcomp->params.egl->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    cap_xcomp->params.egl->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    cap_xcomp->params.egl->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    cap_xcomp->params.egl->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

    cap_xcomp->params.egl->glBindTexture(GL_TEXTURE_2D, 0);
    return texture_id;
}

static int gsr_capture_xcomposite_cuda_start(gsr_capture *cap, AVCodecContext *video_codec_context) {
    gsr_capture_xcomposite_cuda *cap_xcomp = cap->priv;

    if(cap_xcomp->params.follow_focused) {
        cap_xcomp->net_active_window_atom = XInternAtom(cap_xcomp->dpy, "_NET_ACTIVE_WINDOW", False);
        if(!cap_xcomp->net_active_window_atom) {
            fprintf(stderr, "gsr error: gsr_capture_xcomposite_cuda_start failed: failed to get _NET_ACTIVE_WINDOW atom\n");
            return -1;
        }
        cap_xcomp->window = get_focused_window(cap_xcomp->dpy, cap_xcomp->net_active_window_atom);
    } else {
        cap_xcomp->window = cap_xcomp->params.window;
    }

    /* TODO: Do these in tick, and allow error if follow_focused */

    XWindowAttributes attr;
    attr.width = 0;
    attr.height = 0;
    if(!XGetWindowAttributes(cap_xcomp->dpy, cap_xcomp->window, &attr) && !cap_xcomp->params.follow_focused) {
        fprintf(stderr, "gsr error: gsr_capture_xcomposite_cuda_start failed: invalid window id: %lu\n", cap_xcomp->window);
        return -1;
    }

    cap_xcomp->window_size.x = max_int(attr.width, 0);
    cap_xcomp->window_size.y = max_int(attr.height, 0);

    if(cap_xcomp->params.follow_focused)
        XSelectInput(cap_xcomp->dpy, DefaultRootWindow(cap_xcomp->dpy), PropertyChangeMask);

    XSelectInput(cap_xcomp->dpy, cap_xcomp->window, StructureNotifyMask | ExposureMask);

    cap_xcomp->params.egl->eglSwapInterval(cap_xcomp->params.egl->egl_display, 0);
    if(window_texture_init(&cap_xcomp->window_texture, cap_xcomp->dpy, cap_xcomp->window, cap_xcomp->params.egl) != 0 && !cap_xcomp->params.follow_focused) {
        fprintf(stderr, "gsr error: gsr_capture_xcomposite_cuda_start: failed get window texture for window %ld\n", cap_xcomp->window);
        return -1;
    }

    cap_xcomp->texture_size.x = 0;
    cap_xcomp->texture_size.y = 0;

    cap_xcomp->params.egl->glBindTexture(GL_TEXTURE_2D, window_texture_get_opengl_texture_id(&cap_xcomp->window_texture));
    cap_xcomp->params.egl->glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &cap_xcomp->texture_size.x);
    cap_xcomp->params.egl->glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, &cap_xcomp->texture_size.y);
    cap_xcomp->params.egl->glBindTexture(GL_TEXTURE_2D, 0);

    cap_xcomp->texture_size.x = max_int(2, even_number_ceil(cap_xcomp->texture_size.x));
    cap_xcomp->texture_size.y = max_int(2, even_number_ceil(cap_xcomp->texture_size.y));

    video_codec_context->width = cap_xcomp->texture_size.x;
    video_codec_context->height = cap_xcomp->texture_size.y;

    if(cap_xcomp->params.region_size.x > 0 && cap_xcomp->params.region_size.y > 0) {
        video_codec_context->width = max_int(2, even_number_ceil(cap_xcomp->params.region_size.x));
        video_codec_context->height = max_int(2, even_number_ceil(cap_xcomp->params.region_size.y));
    }

    cap_xcomp->target_texture_id = gl_create_texture(cap_xcomp, video_codec_context->width, video_codec_context->height);
    if(cap_xcomp->target_texture_id == 0) {
        fprintf(stderr, "gsr error: gsr_capture_xcomposite_cuda_start: failed to create opengl texture\n");
        gsr_capture_xcomposite_cuda_stop(cap, video_codec_context);
        return -1;
    }

    if(!gsr_cuda_load(&cap_xcomp->cuda, cap_xcomp->dpy, cap_xcomp->params.overclock)) {
        gsr_capture_xcomposite_cuda_stop(cap, video_codec_context);
        return -1;
    }

    if(!cuda_create_codec_context(cap_xcomp, video_codec_context)) {
        gsr_capture_xcomposite_cuda_stop(cap, video_codec_context);
        return -1;
    }

    if(!cuda_register_opengl_texture(cap_xcomp)) {
        gsr_capture_xcomposite_cuda_stop(cap, video_codec_context);
        return -1;
    }

    cap_xcomp->window_resize_timer = clock_get_monotonic_seconds();
    return 0;
}

static void gsr_capture_xcomposite_cuda_stop(gsr_capture *cap, AVCodecContext *video_codec_context) {
    gsr_capture_xcomposite_cuda *cap_xcomp = cap->priv;

    if(cap_xcomp->cuda.cu_ctx) {
        CUcontext old_ctx;
        cap_xcomp->cuda.cuCtxPushCurrent_v2(cap_xcomp->cuda.cu_ctx);

        if(cap_xcomp->cuda_graphics_resource) {
            cap_xcomp->cuda.cuGraphicsUnmapResources(1, &cap_xcomp->cuda_graphics_resource, 0);
            cap_xcomp->cuda.cuGraphicsUnregisterResource(cap_xcomp->cuda_graphics_resource);
        }

        cap_xcomp->cuda.cuCtxPopCurrent_v2(&old_ctx);
    }

    window_texture_deinit(&cap_xcomp->window_texture);

    if(cap_xcomp->target_texture_id) {
        cap_xcomp->params.egl->glDeleteTextures(1, &cap_xcomp->target_texture_id);
        cap_xcomp->target_texture_id = 0;
    }

    if(video_codec_context->hw_device_ctx)
        av_buffer_unref(&video_codec_context->hw_device_ctx);
    if(video_codec_context->hw_frames_ctx)
        av_buffer_unref(&video_codec_context->hw_frames_ctx);

    gsr_cuda_unload(&cap_xcomp->cuda);

    if(cap_xcomp->dpy) {
        // TODO: This causes a crash, why? maybe some other library dlclose xlib and that also happened to unload this???
        //XCloseDisplay(cap_xcomp->dpy);
        cap_xcomp->dpy = NULL;
    }
}

static void gsr_capture_xcomposite_cuda_tick(gsr_capture *cap, AVCodecContext *video_codec_context, AVFrame **frame) {
    gsr_capture_xcomposite_cuda *cap_xcomp = cap->priv;

    cap_xcomp->params.egl->glClear(GL_COLOR_BUFFER_BIT);

    bool init_new_window = false;
    while(XPending(cap_xcomp->dpy)) {
        XNextEvent(cap_xcomp->dpy, &cap_xcomp->xev);

        switch(cap_xcomp->xev.type) {
            case DestroyNotify: {
                /* Window died (when not following focused window), so we stop recording */
                if(!cap_xcomp->params.follow_focused && cap_xcomp->xev.xdestroywindow.window == cap_xcomp->window) {
                    cap_xcomp->should_stop = true;
                    cap_xcomp->stop_is_error = false;
                }
                break;
            }
            case Expose: {
                /* Requires window texture recreate */
                if(cap_xcomp->xev.xexpose.count == 0 && cap_xcomp->xev.xexpose.window == cap_xcomp->window) {
                    cap_xcomp->window_resize_timer = clock_get_monotonic_seconds();
                    cap_xcomp->window_resized = true;
                }
                break;
            }
            case ConfigureNotify: {
                /* Window resized */
                if(cap_xcomp->xev.xconfigure.window == cap_xcomp->window && (cap_xcomp->xev.xconfigure.width != cap_xcomp->window_size.x || cap_xcomp->xev.xconfigure.height != cap_xcomp->window_size.y)) {
                    cap_xcomp->window_size.x = max_int(cap_xcomp->xev.xconfigure.width, 0);
                    cap_xcomp->window_size.y = max_int(cap_xcomp->xev.xconfigure.height, 0);
                    cap_xcomp->window_resize_timer = clock_get_monotonic_seconds();
                    cap_xcomp->window_resized = true;
                }
                break;
            }
            case PropertyNotify: {
                /* Focused window changed */
                if(cap_xcomp->params.follow_focused && cap_xcomp->xev.xproperty.atom == cap_xcomp->net_active_window_atom) {
                    init_new_window = true;
                }
                break;
            }
        }
    }

    if(cap_xcomp->params.follow_focused && !cap_xcomp->follow_focused_initialized) {
        init_new_window = true;
    }

    if(init_new_window) {
        Window focused_window = get_focused_window(cap_xcomp->dpy, cap_xcomp->net_active_window_atom);
        if(focused_window != cap_xcomp->window || !cap_xcomp->follow_focused_initialized) {
            cap_xcomp->follow_focused_initialized = true;
            XSelectInput(cap_xcomp->dpy, cap_xcomp->window, 0);
            cap_xcomp->window = focused_window;
            XSelectInput(cap_xcomp->dpy, cap_xcomp->window, StructureNotifyMask | ExposureMask);

            XWindowAttributes attr;
            attr.width = 0;
            attr.height = 0;
            if(!XGetWindowAttributes(cap_xcomp->dpy, cap_xcomp->window, &attr))
                fprintf(stderr, "gsr error: gsr_capture_xcomposite_cuda_tick failed: invalid window id: %lu\n", cap_xcomp->window);

            cap_xcomp->window_size.x = max_int(attr.width, 0);
            cap_xcomp->window_size.y = max_int(attr.height, 0);
            cap_xcomp->window_resized = true;

            window_texture_deinit(&cap_xcomp->window_texture);
            window_texture_init(&cap_xcomp->window_texture, cap_xcomp->dpy, cap_xcomp->window, cap_xcomp->params.egl); // TODO: Do not do the below window_texture_on_resize after this
            
            cap_xcomp->texture_size.x = 0;
            cap_xcomp->texture_size.y = 0;

            cap_xcomp->params.egl->glBindTexture(GL_TEXTURE_2D, window_texture_get_opengl_texture_id(&cap_xcomp->window_texture));
            cap_xcomp->params.egl->glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &cap_xcomp->texture_size.x);
            cap_xcomp->params.egl->glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, &cap_xcomp->texture_size.y);
            cap_xcomp->params.egl->glBindTexture(GL_TEXTURE_2D, 0);

            cap_xcomp->texture_size.x = min_int(video_codec_context->width, max_int(2, even_number_ceil(cap_xcomp->texture_size.x)));
            cap_xcomp->texture_size.y = min_int(video_codec_context->height, max_int(2, even_number_ceil(cap_xcomp->texture_size.y)));
        }
    }

    const double window_resize_timeout = 1.0; // 1 second
    if(!cap_xcomp->created_hw_frame || (cap_xcomp->window_resized && clock_get_monotonic_seconds() - cap_xcomp->window_resize_timer >= window_resize_timeout)) {
        cap_xcomp->window_resized = false;
        if(window_texture_on_resize(&cap_xcomp->window_texture) != 0) {
            fprintf(stderr, "gsr error: gsr_capture_xcomposite_cuda_tick: window_texture_on_resize failed\n");
            //cap_xcomp->should_stop = true;
            //cap_xcomp->stop_is_error = true;
            return;
        }

        cap_xcomp->texture_size.x = 0;
        cap_xcomp->texture_size.y = 0;

        cap_xcomp->params.egl->glBindTexture(GL_TEXTURE_2D, window_texture_get_opengl_texture_id(&cap_xcomp->window_texture));
        cap_xcomp->params.egl->glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &cap_xcomp->texture_size.x);
        cap_xcomp->params.egl->glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, &cap_xcomp->texture_size.y);
        cap_xcomp->params.egl->glBindTexture(GL_TEXTURE_2D, 0);

        cap_xcomp->texture_size.x = min_int(video_codec_context->width, max_int(2, even_number_ceil(cap_xcomp->texture_size.x)));
        cap_xcomp->texture_size.y = min_int(video_codec_context->height, max_int(2, even_number_ceil(cap_xcomp->texture_size.y)));

        if(!cap_xcomp->created_hw_frame) {
            cap_xcomp->created_hw_frame = true;
            av_frame_free(frame);
            *frame = av_frame_alloc();
            if(!frame) {
                fprintf(stderr, "gsr error: gsr_capture_xcomposite_cuda_tick: failed to allocate frame\n");
                cap_xcomp->should_stop = true;
                cap_xcomp->stop_is_error = true;
                return;
            }
            (*frame)->format = video_codec_context->pix_fmt;
            (*frame)->width = video_codec_context->width;
            (*frame)->height = video_codec_context->height;
            (*frame)->color_range = video_codec_context->color_range;
            (*frame)->color_primaries = video_codec_context->color_primaries;
            (*frame)->color_trc = video_codec_context->color_trc;
            (*frame)->colorspace = video_codec_context->colorspace;
            (*frame)->chroma_location = video_codec_context->chroma_sample_location;

            if(av_hwframe_get_buffer(video_codec_context->hw_frames_ctx, *frame, 0) < 0) {
                fprintf(stderr, "gsr error: gsr_capture_xcomposite_cuda_tick: av_hwframe_get_buffer failed\n");
                cap_xcomp->should_stop = true;
                cap_xcomp->stop_is_error = true;
                return;
            }
        }

        // Clear texture with black background because the source texture (window_texture_get_opengl_texture_id(&cap_xcomp->window_texture))
        // might be smaller than cap_xcomp->target_texture_id
        cap_xcomp->params.egl->glClearTexImage(cap_xcomp->target_texture_id, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
    }
}

static bool gsr_capture_xcomposite_cuda_should_stop(gsr_capture *cap, bool *err) {
    gsr_capture_xcomposite_cuda *cap_xcomp = cap->priv;
    if(cap_xcomp->should_stop) {
        if(err)
            *err = cap_xcomp->stop_is_error;
        return true;
    }

    if(err)
        *err = false;
    return false;
}

static int gsr_capture_xcomposite_cuda_capture(gsr_capture *cap, AVFrame *frame) {
    gsr_capture_xcomposite_cuda *cap_xcomp = cap->priv;

    vec2i source_pos = { 0, 0 };
    vec2i source_size = cap_xcomp->texture_size;

    if(cap_xcomp->window_texture.texture_id != 0) {
        while(cap_xcomp->params.egl->glGetError()) {}
        /* TODO: Remove this copy, which is only possible by using nvenc directly and encoding window_pixmap.target_texture_id */
        cap_xcomp->params.egl->glCopyImageSubData(
            window_texture_get_opengl_texture_id(&cap_xcomp->window_texture), GL_TEXTURE_2D, 0, source_pos.x, source_pos.y, 0,
            cap_xcomp->target_texture_id, GL_TEXTURE_2D, 0, 0, 0, 0,
            source_size.x, source_size.y, 1);
        unsigned int err = cap_xcomp->params.egl->glGetError();
        if(err != 0) {
            static bool error_shown = false;
            if(!error_shown) {
                error_shown = true;
                fprintf(stderr, "gsr error: gsr_capture_xcomposite_cuda_capture: glCopyImageSubData failed, gl error: %d\n", err);
            }
        }
    }
    cap_xcomp->params.egl->eglSwapBuffers(cap_xcomp->params.egl->egl_display, cap_xcomp->params.egl->egl_surface);

    frame->linesize[0] = frame->width * 4;
    //frame->linesize[0] = frame->width * 1;
    //frame->linesize[1] = frame->width * 1;
    //frame->linesize[2] = frame->width * 1;

    CUDA_MEMCPY2D memcpy_struct;
    memcpy_struct.srcXInBytes = 0;
    memcpy_struct.srcY = 0;
    memcpy_struct.srcMemoryType = CU_MEMORYTYPE_ARRAY;

    memcpy_struct.dstXInBytes = 0;
    memcpy_struct.dstY = 0;
    memcpy_struct.dstMemoryType = CU_MEMORYTYPE_DEVICE;

    memcpy_struct.srcArray = cap_xcomp->mapped_array;
    memcpy_struct.dstDevice = (CUdeviceptr)frame->data[0];
    memcpy_struct.dstPitch = frame->linesize[0];
    memcpy_struct.WidthInBytes = frame->width * 4;//frame->width * 1;
    memcpy_struct.Height = frame->height;
    cap_xcomp->cuda.cuMemcpy2D_v2(&memcpy_struct);

    //frame->data[1] = frame->data[0];
    //frame->data[2] = frame->data[0];

    return 0;
}

static void gsr_capture_xcomposite_cuda_destroy(gsr_capture *cap, AVCodecContext *video_codec_context) {
    if(cap->priv) {
        gsr_capture_xcomposite_cuda_stop(cap, video_codec_context);
        free(cap->priv);
        cap->priv = NULL;
    }
    free(cap);
}

gsr_capture* gsr_capture_xcomposite_cuda_create(const gsr_capture_xcomposite_cuda_params *params) {
    if(!params) {
        fprintf(stderr, "gsr error: gsr_capture_xcomposite_cuda_create params is NULL\n");
        return NULL;
    }

    gsr_capture *cap = calloc(1, sizeof(gsr_capture));
    if(!cap)
        return NULL;

    gsr_capture_xcomposite_cuda *cap_xcomp = calloc(1, sizeof(gsr_capture_xcomposite_cuda));
    if(!cap_xcomp) {
        free(cap);
        return NULL;
    }

    Display *display = XOpenDisplay(NULL);
    if(!display) {
        fprintf(stderr, "gsr error: gsr_capture_xcomposite_cuda_create failed: XOpenDisplay failed\n");
        free(cap);
        free(cap_xcomp);
        return NULL;
    }

    cap_xcomp->dpy = display;
    cap_xcomp->params = *params;
    
    *cap = (gsr_capture) {
        .start = gsr_capture_xcomposite_cuda_start,
        .tick = gsr_capture_xcomposite_cuda_tick,
        .should_stop = gsr_capture_xcomposite_cuda_should_stop,
        .capture = gsr_capture_xcomposite_cuda_capture,
        .destroy = gsr_capture_xcomposite_cuda_destroy,
        .priv = cap_xcomp
    };

    return cap;
}