Record Replay¶
This example records the DRP2 frame stream from an offscreen view and replays it
Preview¶
No screenshot
Run And Adapt¶
Commands below assume a Datoviz source checkout and start at the repository root. Use your configured build environment; Python routes additionally require local bindings.
| Route | Availability | Command or action |
|---|---|---|
| C | Canonical native source | just example-c runtime/record_replay (build and run), or rerun ./build/examples/c/runtime/record_replay |
| Python | No verified adaptation on this page | Start from the C source. |
| Browser | Native only | DVZR app recording and replay use native runtime capture plumbing |
Use this example as capability or integration evidence, not as a minimal copy-paste template. Start from the nearest supported, copy-safe example and add this feature after verifying the linked API reference.
What To Look For¶
The recorded scene is a five-point visual with explicit position, color, and diameter arrays. The app records the backend-neutral rendering commands produced for the frame, not a video or editable scene file. It writes the DVZR recording plus two PNGs, one captured from the original offscreen view and one captured from the replay view; compare those images to verify that replaying the command stream reproduces the same rendered frame.
This experimental workflow is useful when you need visual regression artifacts or a compact trace for renderer debugging without keeping the original app process alive.
Source¶
/*
* Copyright (c) 2021 Cyrille Rossant and contributors. All rights reserved.
* Licensed under the MIT license. See LICENSE file in the project root for details.
* SPDX-License-Identifier: MIT
*/
/* record_replay - This example records the DRP2 frame stream from an offscreen view and replays it
* from a DVZR recording.
*
* What to look for: the recorded scene is a five-point visual with explicit position, color, and
* diameter arrays. The app records the backend-neutral rendering commands produced for the frame,
* not a video or editable scene file. It writes the DVZR recording plus two PNGs, one captured from
* the original offscreen view and one captured from the replay view; compare those images to verify
* that replaying the command stream reproduces the same rendered frame.
*
* This experimental workflow is useful when you need visual regression artifacts or a compact trace
* for renderer debugging without keeping the original app process alive.
*
* Scenario: runtime_record_replay
* Style: runtime, native app
*
* Build: just example-c runtime/record_replay
* Run: ./build/examples/c/runtime/record_replay
*/
/*************************************************************************************************/
/* Includes */
/*************************************************************************************************/
#include <stdint.h>
#include "datoviz/app.h"
#include "datoviz/canvas/enums.h"
#include "datoviz/scene.h"
#include "example_common.h"
#include "example_style.h"
/*************************************************************************************************/
/* Constants */
/*************************************************************************************************/
#define WIDTH EXAMPLE_OUTPUT_WIDTH
#define HEIGHT EXAMPLE_OUTPUT_HEIGHT
#define POINT_COUNT 5u
/*************************************************************************************************/
/* Helpers */
/*************************************************************************************************/
/**
* Build the retained scene that will be recorded.
*
* @param scene target scene
* @return figure containing the scene, or NULL
*/
static DvzFigure* _record_replay_figure(DvzScene* scene)
{
if (scene == NULL)
return NULL;
DvzFigure* figure = dvz_figure(scene, WIDTH, HEIGHT, 0);
DvzPanel* panel = figure != NULL ? dvz_panel_full(figure) : NULL;
DvzVisual* point = dvz_point(scene, 0);
if (figure == NULL || panel == NULL || point == NULL)
return NULL;
example_graphite_cyan_set_panel_background(panel);
vec3 positions[POINT_COUNT] = {
{-0.70f, -0.45f, 0.0f}, {-0.35f, +0.20f, 0.0f}, {+0.00f, -0.05f, 0.0f},
{+0.35f, +0.42f, 0.0f}, {+0.70f, -0.25f, 0.0f},
};
DvzColor colors[POINT_COUNT] = {
example_graphite_cyan_color(EXAMPLE_STYLE_COLOR_ACCENT_PRIMARY),
example_graphite_cyan_color(EXAMPLE_STYLE_COLOR_ACCENT_SECONDARY),
example_graphite_cyan_color(EXAMPLE_STYLE_COLOR_WARNING),
example_graphite_cyan_color(EXAMPLE_STYLE_COLOR_TEXT),
example_graphite_cyan_color(EXAMPLE_STYLE_COLOR_MINOR_TICK),
};
float diameters[POINT_COUNT] = {34.0f, 46.0f, 58.0f, 46.0f, 34.0f};
DvzVisualDataUpdate updates[] = {
{.attr_name = "position", .data = positions, .item_count = POINT_COUNT},
{.attr_name = "color", .data = colors, .item_count = POINT_COUNT},
{.attr_name = "diameter_px", .data = diameters, .item_count = POINT_COUNT},
};
if (dvz_visual_set_data_many(point, updates, 3) != 0)
return NULL;
if (dvz_panel_add_visual(panel, point, NULL) != 0)
return NULL;
return figure;
}
/*************************************************************************************************/
/* Main */
/*************************************************************************************************/
int main(int argc, char** argv)
{
(void)argc;
int ret = 1;
DvzScene* scene = NULL;
DvzApp* app = NULL;
char recording_path[512] = {0};
char original_png[512] = {0};
char replay_png[512] = {0};
example_outpath(argv[0], "record_replay.dvzr", recording_path, sizeof(recording_path));
example_outpath(argv[0], "record_replay_original.png", original_png, sizeof(original_png));
example_outpath(argv[0], "record_replay_replay.png", replay_png, sizeof(replay_png));
scene = dvz_scene();
EXAMPLE_CHECK(scene != NULL, "dvz_scene() failed");
DvzFigure* figure = _record_replay_figure(scene);
EXAMPLE_CHECK(figure != NULL, "failed to build recorded figure");
app = dvz_app(scene);
EXAMPLE_CHECK(app != NULL, "dvz_app() failed (no GPU?)");
DvzView* record_view = dvz_view_offscreen(app, figure, WIDTH, HEIGHT);
EXAMPLE_CHECK(record_view != NULL, "dvz_view_offscreen(record) failed");
EXAMPLE_CHECK(
dvz_view_record_start(record_view, recording_path) == 0, "dvz_view_record_start() failed");
EXAMPLE_CHECK(
dvz_view_render_once(record_view) == DVZ_CANVAS_FRAME_READY, "record render failed");
EXAMPLE_CHECK(dvz_view_record_stop(record_view) == 0, "dvz_view_record_stop() failed");
EXAMPLE_CHECK(
dvz_view_capture_png(record_view, original_png) == 0, "failed to capture recorded frame");
DvzFigure* replay_figure = dvz_figure(scene, WIDTH, HEIGHT, 0);
EXAMPLE_CHECK(replay_figure != NULL, "dvz_figure(replay) failed");
DvzView* replay_view = dvz_view_offscreen(app, replay_figure, WIDTH, HEIGHT);
EXAMPLE_CHECK(replay_view != NULL, "dvz_view_offscreen(replay) failed");
EXAMPLE_CHECK(
dvz_view_replay_start(replay_view, recording_path) == 0, "dvz_view_replay_start() failed");
dvz_view_replay_set_paced(replay_view, false);
EXAMPLE_CHECK(dvz_view_replay_frame_count(replay_view) > 0, "replay has no frames");
EXAMPLE_CHECK(
dvz_view_render_once(replay_view) == DVZ_CANVAS_FRAME_READY, "replay render failed");
EXAMPLE_CHECK(dvz_view_replay_stop(replay_view) == 0, "dvz_view_replay_stop() failed");
EXAMPLE_CHECK(
dvz_view_capture_png(replay_view, replay_png) == 0, "failed to capture replay frame");
dvz_fprintf(stdout, "record_replay: wrote %s\n", recording_path);
dvz_fprintf(stdout, "record_replay: wrote %s\n", original_png);
dvz_fprintf(stdout, "record_replay: wrote %s\n", replay_png);
ret = 0;
cleanup:
if (app != NULL)
dvz_app_destroy(app);
if (scene != NULL)
dvz_scene_destroy(scene);
return ret;
}
Example details
- ID:
runtime_record_replay - Category:
runtime - Lane:
runtime - Status:
experimental - Source:
examples/c/runtime/record_replay.c - Approved adaptation starter:
no - Browser support: Native only
- Browser note: DVZR app recording and replay use native runtime capture plumbing
- Browser capability tags:
native-capture - Validation:
smoke+capture
Data
| Field | Value |
|---|---|
kind |
synthetic |