A game engine based on the light-indexed deferred rendering technique described by Damien Trebilco. Check out https://github.com/dtrebilco/lightindexed-deferredrender
My benchmark scenes of the Crytek Sponza Atrium could not fit on github so you must download them here and put them in the root of this directory tree. The scene uses a re-creation of the Doom3 Hell Knight I got from here and a christmas tree I got from here
This is a CMake project with all dependencies included in the repo. If you know CMake, then stop here and do the normal thing. Otherwise:
mkdir build
cd build
cmake ..
make -j4
./ldraw
The default run mode is LIDR with no shadows in FPS camera mode.
Use:
"benchmark" to run the benchmark scene
"forward" to use forward rendering
"shadows" to turn on shadows
Shadows can also be toggled by pressing '2' on the keyboard. Screenshots can be taken with F12
-Light Indexed Deferred Rendering with up to 4 lights per fragment and 256 total scene lights
-Standard forward rendering for comparison purposes
-Per-light shadow mapping (and point light omnidirectional shadow maps)
-Easily extensible Input class for all of your inputting needs (used by camera and scenegraph)
-FPS Camera like counterstrike. Operates in clip mode right now. Press 'v' to toggle wireframe rendering.
-Scenegraph implementation with things like Pre-baking, Z-prepass, and efficient transform propagation
-Keyframe animation for any node in the scenegraph. Check out out the animation class in inc/!
-ShaderLib: my shader library which can resolve named shader programs if you use my little syntax additions to GLSL. It canonicalizes all uniform locations with a constraint table so updating them at runtime now takes 1 function call instead of 2.
-Light manager that supports point and cone lights. Directional lights are implemented but never used for the demo so I'm not sure they work perfectly.
-Material library for the phong shading model
-Uses ASSIMP as a first-step importer so any assets ASSIMP can handle can theoretically be loaded into LightDraw. Realistically, I have used it with collada, fbx, and 3ds so I know those work.
-Uses SOIL to load textures
-Uses glm for GLSL-like vector math
-Uses lodePNG to record videos and screenshots
-Uses GLFW for rendering context
-Uses GLEW for managing extensions
-Can load voxel objects out of the binvox format
Instead of storing objects and material properties in a G buffer, like traditional deferred rendering, LIDR stores light properties and the fragments they hit. All geometry is then rendered in a forward manner and a "lightmap" texture is sampled to see which lights hit the current fragment. Lights are identified by a number, which is its index in the light array and also its index in a 1D texture containing all of the light properties of the scene. The rendering steps of my implementation are:
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Z Pre-Pass the entire scene into a depth FBO
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(Optional) Render shadow maps for each light
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Construct the Light Index Map by rendering and accumulating light volumes into a full screen quad. All light volumes are implicitly defined as a sphere or a cone. If shadows are desired, apply shadowmapping here by discarding fragments that are in the light's shadow.
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Pack light properties into 1D textures so that the light index can be used to sample the texture and retrieve the light properties
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Draw scene in a forward manner. Make the light properties texture as well as the Light Index Map available to the shader in order to extract which lights hit the current fragment.
Check out the paper for more detailed info.
My Sponza benchmark is basically the Crytek modified Sponza with 693,838 triangles and varying amounts of lights. This is a stress test so every single light is assumed to be dynamic and all light volumes and shadowmaps are re-calculated on every frame. This is why the performance collapses so dramatically with shadows enabled. V-sync is enabled too.
I ran my benchmark scene on this computer:
CPU: intel 5820k
RAM: 64GB 2666MHz
GPU: nvidia gtx 980 ti
OpenGL version string: 4.5.0 NVIDIA 367.57
Linux Kernel: 4.4.0-53-generic
