INTRODUCTION
This is a Vulkan render application with intent to demonstrate some graphics techniques and get familiarity with the new KhrounosGroup API .
The inspiration for the scene was a top down game called Yugioh Capsule Monster,although I have pretty basic skills in art and design of scenarios. Besides the graphics rendering, the program features some very basic game engine concepts such as Entity-Component relationship.
The Render features some topics like PBR Lighting , Directional Shadow Map calculated based on camera frustum , irradiance map and Specular reflections with Image Based Light using the Epic Games split sum approximation.It also features screen space occlusion which uses 26 samples to calculate an occlusion factor.
The illumination is done in a deferred render pass, the deferred pass uses a geometry pass which consists of a collection of buffers that hold geometry information of the scene.
The frame creation process consists of 7 Renderpasses :
Renderpass 1 - Creates the directional shadow Map (1920x1080)
Renderpass 2 - Fill a GBUFFER with ( WorldSpace Normals,Material metallicness and roughness packed togheter, Albedo) (1920x1080)
Renderpass 3 - Creates the ScreenSpace Ambient Occlusion with 56 samples (1920x1080)
Renderpass 4 - Performs a Gausian Blur on the previous on SSAO image with a 4x4 kernel (1920x1080)
"Renderpass 5 - Performs light calculations , Tone Mapping and fill a color attachment which is used to show Bloom Effect. There are two outputs in this renderpass : one is the scene with ilumination calculated, and another witch is the result of what passes in a threshold that selects the brightests areas of the scene. (1920x1080)
Renderpass 6 - Performs Vertical Gausian Blur on the secondary attachment ( the attachment with brigthests areas of the scen ) from the previus pass (1920x1080)
Renderpass 7 - Performs Horizontal Gausian Blur on the attachment outputed at renderpass 6 and add it's result to final image outputed at lighting stage (1920x1080)".
Vulkan provides an awesome feature called subpass, which consists as a local pass inside an renderpass, unfortunately the limitation of such subpass is that it can’t be sampled. That’s the reason I’ve chosen to create multiple renderpasses.
SCREENSHOTS
Overview of the scene - taken in 19/07/2020
WATER
The water effect is created using dudv distortion textures, The perturbations is used to distort texture coordinates and the normal map in X and Y directions. The reflection uses only the skybox , so there is no real time reflection yet. And the refraction uses an albedo texture to represent the the “Board’s ground” . In near future I plan to implement SSR in water .
Reference : https://www.youtube.com/watch?v=HusvGeEDU_U .
SHADOWS
Although the scene has multiple point lights, the only light that cast shadows is the unique directional shadow in the scene. The orthographic projection matrix is calculated based on camera frustum in following way :
First calculate the camera frustum corners in worldSapce.
Calculate the lightSpace position for each of the corners.
Get maximum and minimum values in X,Y,Z and use these values to build the orthographic projection.
Since the inspiration is a top down game,and the level is at height 0 ; the far plane is calculated based on the Height of the Camera.
Reference : https://www.youtube.com/watch?v=o6zDfDkOFIc
Dependencies :
GLM Library to do math calculations. GLFW to create the window. ImGui to create the interface.