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// Copyright (C) 2025 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
/*!
\title Qt Quick 3D - SSGI Lightmap Example
\example ssgilightmap
\ingroup quick3d-examples
\brief An example showing scenes using SSGI and Lightmaps.
\examplecategory {3D}
\meta {tag} {quick, 3d, ssgi, lightmaps}
\meta {docdependencies} {QtQuick3D}
\image {ssgilightmap-screenshot.webp} {A 3D scene showing a cabin bedroom}
This example demonstrates two global illumination techniques available in
Qt Quick 3D: Screen Space Global Illumination (SSGI) and baked lightmaps.
It allows comparing the visual differences and performance characteristics of
real-time and precomputed lighting.
The application includes three common test scenes used to evaluate rendering:
\list
\li Cornell Box -
A classic lighting test setup highlighting diffuse
color bleeding and indirect illumination.
\li Bedroom -
An indoor environment with soft, warm lighting and a
mixture of materials and occluded spaces.
\li Sponza Atrium -
A large architectural test scene with drapery,
arcades, and multiple layers of indirect lighting.
\endlist
Each scene provides a number of predefined camera positions. A built-in
Demo mode automatically cycles through these viewpoints to show how the
lighting behaves from different angles.
The lighting mode can be changed at runtime to one of the following:
\list
\li SSGI -
Enables real-time, screen-space global illumination.
This is controlled through the
\l{QtQuick3D.Helpers::ExtendedSceneEnvironment::ssgiEnabled}
{ssgiEnabled} property of \l
{QtQuick3D.Helpers::ExtendedSceneEnvironment}
{ExtendedSceneEnvironment}. SSGI offers dynamic
indirect lighting suitable for interactive and
animated content, at some performance cost and
with approximations inherent to screen-space
techniques.
\li Baked Lightmaps -
Uses precomputed direct, indirect, or both
lighting stored in texture lightmaps. Lightmap
baking is performed offline by the Qt Quick 3D
Lightmap Baker. See \l{Lightmaps and Global
Illumination}{Lightmap Baking} for details.
This provides high-quality, path-traced illumination with very low
runtime cost, best suited for mostly static environments.
\li Off -
Disables both SSGI and baked lightmaps for comparison against direct
lighting only.
\endlist
\sa {QtQuick3D.Helpers::ExtendedSceneEnvironment::ssgiEnabled}
{ExtendedSceneEnvironment::ssgiEnabled}
\sa {Lightmaps and Global Illumination}
{Lightmap Baking}
*/