Added shadow mapping for directional lights

[adriengivry]

Description

Implementation of shadow mapping!

• Shadow casting AND receiving is enabled on the Default.ovmat material by default.
• When a new material is created, these 2 settings are OFF by default.
• Directional lights (components) have a "Shadow casting" option that is OFF by default.
• Includes 2 implementations for shadows: hard-shadows, and soft-shadows/PCF (default).
• Introduces a TextureHandle class, which wraps an OpenGL texture ID, and can be passed as a uniform. This TextureHandle class is used by the framebuffer to expose its rendered image.
• Texture now inherits from TextureHandle.
• ShadowRenderPass added: handles the rendering of shadow casters in the shadow map
• ShadowRenderFeature added: ensures that the shadow map is properly bound to each entity set to receive shadows.
• Shadow area size is exposed through the CDirectionaLight component. Changing this setting will change the radius of the shadow (bigger radius = less precision)
• Shadow area size is exposed through the CDirectionaLight component.
• Shadow follow camera is a setting exposed through the CDirectionaLight component allowing the directional light to use the position of the camera as a source for its light space matrix (for shadow map rendering), making shadows "follow" the camera around, instead of being static.
• Added a singleUse parameter to Material::Set, for properties that shouldn't be stored after drawing (i.e. shadow maps texture handles)

Notes

This PR also updates OvEditor and OvGame premake files to disable fastuptodate, which forces both project to trigger their post-build command before any run (resulting in resources being properly updated between runs, even if no source file changed).

Limitations

• Only one directional light can cast shadows per scene, if more are found, warnings will be logged in the console and the subsequent lights will be ignored.
• Shadow casting passes use a custom Shadow.ovfx shader, which doesn't vertex transformations outside of the regular modelMatrix * vec4(geo_Pos, 1.0);, which could result in shaders using instancing or vertex displacement to not cast shadows properly. One way to mitigate this would be to add a way to specify a shader override for certain passes (like shadows), through the material. However this change should be made in a separate PR.
• Shadow map resolution isn't exposed at the moment, as changing it could introduce shadow acne (the shadow bias being hard coded, not depending on the shadow map resolution).

To-Do

• Move shadow implementation outside of the editor (Rendering/Core)
• Cleanup shader code
• Make it use scene directional lights instead of the manually set one
• Take ambient light into account
• Add options to enable/disable shadow casting/receiving
• Make sure the ShadowRenderFeature only runs on materials set to receive shadow
• Cleanup frame buffer
• Investigate better architecture for Texture/TextureHandle
• Increase directional light radius
• Make it work with other lighting models (PBR...)
• Fix material exception on edit for the 2nd time (related to std::any usage)
• Make shadow area size changeable
• Validate frustum behaviour (this feature is broken anyway, so I guess we'll see later)
• Add prefix to exclude some uniforms from being exposed to the material editor
• Expose new methods & settings to lua
• Add new methods & settings to the wiki

Related Issues

Fixes #250
Fixes #313

Screenshots

Resources

Mostly followed:
https://learnopengl.com/Advanced-Lighting/Shadows/Shadow-Mapping

[adriengivry]

Getting some weird logs in the console with the shadow mapping. I need to investigate!

[ERROR] 2024-11-21_12-34-55 OpenGL Debug Message:
Debug message (1282): GL_INVALID_OPERATION error generated. Texture name does not refer to a texture object generated by OpenGL.
Source: API
Type: Error
Severity: High

Edit: Fixed! Introduced singleUse parameter in Material::Set