Introduce Night

Release 0.14.0

STPStarfield

The highlight in this release is this procedurally rendered and animated starfield. Like most others renderers, it comes with the main renderer class STPStarfield, a setting class STPStarfieldSetting, and finally a shader STPStarfield.frag.

To allow simultaneously rendering multiple environments, some improvements have been done to STPScenePipeline:

• Add an extinction environment rendering cache for holding temporary environment colours before blended with other scene objects.
• Add a visibility switch for STPEnvironmentObject.
• All environment colours are now summed together instead of overwriting.
• Replace small range-based for-loop with std::for_each for clarity.
• Add ambient light at night.

General fixes and improvement

• Fix a mistake in STPGaussianFilter for forgetting to assign uniform for image depth sampler.
• Remove use of element buffer in STPScreen and use triangle fan instead.
• Avoid explicit call to bindless texture destructor during random texture generation in STPHeightfieldTerrain which causes the destructor to be called twice at move construction.
• Add STPSimpleScreenBindlessFrameBuffer in STPScreen to allow using screen colour texture attachment on a framebuffer as a bindless target.
• Refactor STPBidirectionalScattering with the newly introduced STPSimpleScreenBindlessFrameBuffer.
• Fix a unspecified argument evaluation order in erosion kernel in STPHeightfieldKernel.
• Ambient occlusion blending now only enables at output to avoid doing the useless 1.0 x anything = anything stuff.
• Don't clear G-Buffer every frame because each pixel is read only by exactly one of the responsible shading invocation.
• Fix some incorrect code style.
• Improve STPLightSpectrum to allow supporting different channel types.

Refactor environment object rendering

• Add STPSkybox; similar to STPScreen, it is used by environment renderers that require an axis-aligned origin-centred skybox.
• Refactor STPSun to make it benefits from the new skybox renderer.
• Add projection view rotation matrix in STPCameraInformation.