add custom fragment shaders

Author: ntsh-oni

source/fragment_shader/index.rst

@@ -0,0 +1,120 @@
+Fragment Shader
+===============
+
+The :doc:`/types/Renderable/index` :doc:`/entity_component_system/component/index` accepts custom fragment shaders.
+
+These fragment shaders are written in GLSL and have some special variables.
+
+Inputs
+------
+
+.. list-table::
+	:width: 100%
+	:header-rows: 1
+	:class: code-table
+
+	* - Name
+	  - Type
+	  - Description
+	* - NtshEngn_position
+	  - vec3
+	  - The fragment's position, in **world-space**.
+	* - NtshEngn_normal
+	  - vec3
+	  - The fragment's normal.
+	* - NtshEngn_tangent
+	  - vec3
+	  - The fragment's tangent.
+	* - NtshEngn_bitangent
+	  - vec3
+	  - The fragment's bitangent.
+	* - NtshEngn_uv
+	  - vec2
+	  - The fragment's texture coordinates.
+	* - NtshEngn_tbn
+	  - mat3
+	  - The fragment's Tangent-Bitangent-Normal matrix.
+	* - NtshEngn_diffuseTextureSampler
+	  - sampler2D
+	  - The object's material's diffuse texture.
+	* - NtshEngn_normalTextureSampler
+	  - sampler2D
+	  - The object's material's normal texture.
+	* - NtshEngn_metalnessTextureSampler
+	  - sampler2D
+	  - The object's material's metalness texture.
+	* - NtshEngn_roughnessTextureSampler
+	  - sampler2D
+	  - The object's material's roughness texture.
+	* - NtshEngn_occlusionTextureSampler
+	  - sampler2D
+	  - The object's material's occlusion texture.
+	* - NtshEngn_emissiveTextureSampler
+	  - sampler2D
+	  - The object's material's emissive texture.
+	* - NtshEngn_emissiveFactor
+	  - float
+	  - The object's material's metalness factor.
+	* - NtshEngn_alphaCutoff
+	  - float
+	  - The object's material's alpha cutoff.
+	* - NtshEngn_scaleUV
+	  - vec2
+	  - The object's material's UV scale.
+	* - NtshEngn_offsetUV
+	  - vec2
+	  - The object's material's UV offset.
+	* - NtshEngn_useTriplanarMapping
+	  - bool
+	  - ``true`` if the object's material uses triplanar mapping, else, ``false``.
+	* - NtshEngn_directionalLightCount
+	  - uint
+	  - The number of directional lights in the scene.
+	* - NtshEngn_directionalLight(i)
+	  - :doc:`/types/Light/index`
+	  - The *i*th directional light.
+	* - NtshEngn_pointLightCount
+	  - uint
+	  - The number of point lights in the scene.
+	* - NtshEngn_pointLight(i)
+	  - :doc:`/types/Light/index`
+	  - The *i*th point light.
+	* - NtshEngn_spotLightCount
+	  - uint
+	  - The number of spot lights in the scene.
+	* - NtshEngn_spotLight(i)
+	  - :doc:`/types/Light/index`
+	  - The *i*th spot light.
+	* - NtshEngn_ambientLightCount
+	  - uint
+	  - The number of ambient lights in the scene.
+	* - NtshEngn_ambientLight(i)
+	  - :doc:`/types/Light/index`
+	  - The *i*th ambient light.
+	* - NtshEngn_time
+	  - float
+	  - The time since the application's launch, in **seconds**.
+	* - NtshEngn_cameraPosition
+	  - vec3
+	  - The camera's position, in **world-space**.
+	* - NtshEngn_useReversedDepth
+	  - bool
+	  - ``true`` if the graphics module uses reversed depth (*1* is close, *0* is far), else, ``false`` (*0* is close, *1* is far).
+
+Inputs
+------
+
+.. list-table::
+	:width: 100%
+	:header-rows: 1
+	:class: code-table
+
+	* - Name
+	  - Type
+	  - Description
+	* - NtshEngn_outColor
+	  - vec4
+	  - The output color.
+	* - NtshEngn_outDepth
+	  - float
+	  - The output depth.

source/index.rst

@@ -18,6 +18,8 @@ NutshellEngine
 
 	./asset_manager/index.rst
 
+	./fragment_shader/index.rst
+
 	./frame_limiter/index.rst
 
 	./job_system/index.rst

source/types/Renderable/index.rst

@@ -18,6 +18,9 @@ Variables
 	* - material
 	  - :doc:`/types/Material/index`
 	  - The :doc:`/types/Material/index` to use.
+	* - fragmentShader
+	  - `std::string <https://en.cppreference.com/w/cpp/string/basic_string>`_
+	  - The custom `/types/fragment_shader/index` to use. If empty, the graphics module's default fragment shader will be used.
 
 Notes
 -----
@@ -57,3 +60,7 @@ JSON for the :doc:`/file_formats/ntsn/index` scene file format:
 			  - String
 			  - The path to the material.
 			  - Any path to a material.
+			* - fragmentShaderPath
+			  - String
+			  - The path to the fragment shader.
+			  - Any path to a fragment shader.