History: Enhanced CelShading
Preview of version: 2
Table of contents
Description
This is an enhanced version of Ogre's CelShading CG program and material. It adds the support of decal textures, dynamic ambient lighting, specular texture mapping, edge coloring, and light attenuation. Keep in mind that when using this shader, it will take more resources than the basic example that comes with Ogre.
The material and cg program below may look confusing, but do not worry, you do not have to understand the works completely in order to include it in your own materials.
CelShading.cg
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// //Basic lighting functions // void lighting_vp(float4 position : POSITION, float3 normal : NORMAL, // outputs out float4 oPosition : POSITION, out float diffuse : TEXCOORD0, // parameters uniform float3 lightPosition, // object space uniform float4 lightAttenuation, uniform float4x4 worldViewProj) { // calculate output position oPosition = mul(worldViewProj, position); // calculate light vector float3 N = normalize(normal); float3 L = normalize(lightPosition - position.xyz); //Calculate distance from light to object. float lightDist = length( lightPosition - position.xyz ); float luminosity = 0; if( lightAttenuation.x > lightDist) luminosity = 1.0 / ( lightAttenuation.y + lightAttenuation.z*lightDist + lightAttenuation.w*(lightDist*lightDist) ); // Calculate diffuse component diffuse = max(dot(N, L) , 0)*luminosity; } void lighting_fp(float diffuseIn : TEXCOORD0, out float4 colour : COLOR, uniform sampler1D diffuseRamp : register(s0)) { // Step functions from textures diffuseIn = tex1D(diffuseRamp, diffuseIn).x; colour = diffuseIn; } // //Specular // void specular_vp(float4 position : POSITION, float3 normal : NORMAL, // outputs out float4 oPosition : POSITION, out float specular : TEXCOORD0, float2 texCoord : TEXCOORD0, out float2 uv : TEXCOORD1, // parameters uniform float3 lightPosition, // object space uniform float4 lightAttenuation, uniform float3 eyePosition, // object space uniform float4 shininess, uniform float4x4 worldViewProj) { // calculate output position oPosition = mul(worldViewProj, position); // calculate light vector float3 N = normalize(normal); float3 L = normalize(lightPosition - position.xyz); // Calculate specular component float3 E = normalize(eyePosition - position.xyz); float3 H = normalize(L + E); //Calculate distance from light to object. float lightDist = length( lightPosition - position.xyz ); float luminosity = 0; if( lightAttenuation.x > lightDist) luminosity = 1.0 / ( lightAttenuation.y + lightAttenuation.z*lightDist + lightAttenuation.w*(lightDist*lightDist) ); specular = pow(max(dot(N, H), 0), shininess)*luminosity; uv = texCoord; } void specular_fp(float specularIn : TEXCOORD0, float2 uv : TEXCOORD1, out float4 colour : COLOR, uniform float4 specular, uniform sampler1D specularRamp : register(s0)) { // Step functions from textures specularIn = tex1D(specularRamp, specularIn).x; colour = specular * specularIn; } // //Specular with specular mapping image // void specularTex_fp(float specularIn : TEXCOORD0, float2 uv : TEXCOORD1, out float4 colour : COLOR, uniform float4 specular, uniform sampler1D specularRamp : register(s0), uniform sampler2D specMap : register(s1)) { // Step functions from textures specularIn = tex1D(specularRamp, specularIn).x; float4 specValue = tex2D(specMap, uv); colour = specular * specValue * specularIn; } // //Basic ambent lighting // void ambientOneTexture_vp(float4 position : POSITION, float2 uv : TEXCOORD0, out float4 oPosition : POSITION, out float2 oUv : TEXCOORD0, out float4 colour : COLOR, uniform float4x4 worldViewProj, uniform float4 ambient, uniform float4 diffuse) { oPosition = mul(worldViewProj, position); oUv = uv; colour = diffuse*ambient; } // //Edge shading // void celEdge_vp(float4 position : POSITION, float2 uv : TEXCOORD0, float3 normal : NORMAL, out float4 oPosition : POSITION, out float edge : TEXCOORD0, uniform float4x4 worldViewProj, uniform float3 eyePosition ) { oPosition = mul(worldViewProj, position); float3 N = normalize(normal); float3 E = normalize(eyePosition - position.xyz); edge = max(dot(N, E), 0); } void celEdge_fp(float edge : TEXCOORD0, out float4 colour : COLOR, uniform float4 edgeColor, uniform sampler1D edgeRamp : register(s0)) { edge = tex1D(edgeRamp, edge).x; colour = (1-edge)*edgeColor; }
CelShading.material
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// A really basic ambient pass program, support for one texture coodinate set vertex_program AmbientOneTexture cg { source CelShading.cg entry_point ambientOneTexture_vp profiles vs_1_1 arbvp1 default_params { param_named_auto worldViewProj worldviewproj_matrix param_named_auto ambient ambient_light_colour param_named diffuse float4 1 1 1 1 } } vertex_program CelEdgeVP cg { source CelShading.cg entry_point celEdge_vp profiles vs_1_1 arbvp1 default_params { param_named_auto worldViewProj worldviewproj_matrix param_named_auto eyePosition camera_position_object_space } } fragment_program CelEdgeFP cg { source CelShading.cg entry_point celEdge_fp profiles ps_1_1 arbfp1 fp20 default_params { param_named edgeColor float4 0 0 0 1 } } vertex_program CelShadingVP cg { source CelShading.cg entry_point lighting_vp profiles vs_1_1 arbvp1 default_params { param_named_auto lightPosition light_position_object_space 0 param_named_auto lightAttenuation light_attenuation 0 param_named_auto worldViewProj worldviewproj_matrix } } fragment_program CelShadingFP cg { source CelShading.cg entry_point lighting_fp profiles ps_1_1 arbfp1 fp20 } vertex_program CelSpecularVP cg { source CelShading.cg entry_point specular_vp profiles vs_1_1 arbvp1 default_params { param_named_auto lightPosition light_position_object_space 0 param_named_auto lightAttenuation light_attenuation 0 param_named_auto eyePosition camera_position_object_space param_named_auto worldViewProj worldviewproj_matrix param_named shininess float 10 } } fragment_program CelSpecularFP cg { source CelShading.cg entry_point specular_fp profiles ps_1_1 arbfp1 fp20 } fragment_program CelSpecularTexFP cg { source CelShading.cg entry_point specularTex_fp profiles ps_1_1 arbfp1 fp20 } material CelShading { technique { set $diffuse "1 1 1 1" set $specular "1 1 1 1" set $edge "0 0 0 1" set $shininess "25" // Base ambient pass pass ambient { // base colours, not needed for rendering, but as information // to lighting pass categorisation routine ambient 1 1 1 diffuse 0 0 0 specular 0 0 0 0 // Really basic vertex program // NB we don't use fixed function here because GL does not like // mixing fixed function and vertex programs, depth fighting can // be an issue vertex_program_ref AmbientOneTexture { } } pass perlight { ambient 0 0 0 iteration once_per_light scene_blend add vertex_program_ref CelShadingVP { } fragment_program_ref CelShadingFP { } texture_unit { texture cel_shading_diffuse.png 1d tex_address_mode clamp filtering none colour_op replace } } pass decal { lighting off vertex_program_ref AmbientOneTexture { param_named_auto worldViewProj worldviewproj_matrix param_named ambient float4 1 1 1 1 param_named diffuse float4 $diffuse } scene_blend dest_colour zero texture_unit decalmap { } } pass specular { ambient 0 0 0 iteration once_per_light scene_blend add vertex_program_ref CelSpecularVP { // map shininess from custom renderable param 1 param_named shininess float $shininess } fragment_program_ref CelSpecularFP { // map specular from custom renderable param 2 param_named specular float4 $specular } texture_unit { texture cel_shading_specular.png 1d tex_address_mode clamp filtering none colour_op replace } } pass edge { scene_blend alpha_blend // base colours, not needed for rendering, but as information // to lighting pass categorisation routine ambient 1 1 1 diffuse 0 0 0 specular 0 0 0 0 // Really basic vertex program // NB we don't use fixed function here because GL does not like // mixing fixed function and vertex programs, depth fighting can // be an issue vertex_program_ref CelEdgeVP { } fragment_program_ref CelEdgeFP { param_named edgeColor float4 $edge } texture_unit { texture cel_shading_edge.png 1d tex_address_mode clamp filtering none } } } } material CelShadingSpecular { technique { set $diffuse "1 1 1 1" set $specular "1 1 1 1" set $edge "0 0 0 1" set $shininess "25" // Base ambient pass pass ambient { // base colours, not needed for rendering, but as information // to lighting pass categorisation routine ambient 1 1 1 diffuse 0 0 0 specular 0 0 0 0 // Really basic vertex program // NB we don't use fixed function here because GL does not like // mixing fixed function and vertex programs, depth fighting can // be an issue vertex_program_ref AmbientOneTexture { } } pass perlight { ambient 0 0 0 iteration once_per_light scene_blend add vertex_program_ref CelShadingVP { } fragment_program_ref CelShadingFP { } texture_unit { texture cel_shading_diffuse.png 1d tex_address_mode clamp filtering none colour_op replace } } pass decal { lighting off vertex_program_ref AmbientOneTexture { param_named_auto worldViewProj worldviewproj_matrix param_named ambient float4 1 1 1 1 param_named diffuse float4 $diffuse } scene_blend dest_colour zero texture_unit decalmap { } } pass specular { ambient 0 0 0 iteration once_per_light scene_blend add vertex_program_ref CelSpecularVP { // map shininess from custom renderable param 1 param_named shininess float $shininess } fragment_program_ref CelSpecularTexFP { // map specular from custom renderable param 2 param_named specular float4 $specular } texture_unit { texture cel_shading_specular.png 1d tex_address_mode clamp filtering none colour_op replace } texture_unit specMap { texture white.png } } pass edge { scene_blend alpha_blend // base colours, not needed for rendering, but as information // to lighting pass categorisation routine ambient 1 1 1 diffuse 0 0 0 specular 0 0 0 0 // Really basic vertex program // NB we don't use fixed function here because GL does not like // mixing fixed function and vertex programs, depth fighting can // be an issue vertex_program_ref CelEdgeVP { } fragment_program_ref CelEdgeFP { param_named edgeColor float4 $edge } texture_unit { texture cel_shading_edge.png 1d tex_address_mode clamp filtering none } } } }
Usage
You need to have three textures in order for the material to work, you can get them from Ogre's media/materials/textures directory: cel_shading_edge.png, cel_shading_diffuse.png, and cel_shading_specular.png. You will have to modify cel_shading_diffuse.png and change the left edge of the image to black instead of grey.
You can define two variables very much like in regular materials: diffuse and specular. There are two more variables: edge and shininess, edge is the color of the outline over the mesh. For texturing, you would define the pass: decal, then use the texture_unit: decalmap, and insert your texture.
This is an example material overriding the OgreHead Mesh's materials with the CelShading materials:
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import * from "CelShading.material" material Ogre/Skin : CelShadingSpecular { technique { set $specular "0.3 0.3 0.3 1" pass decal { texture_unit decalmap { texture GreenSkin.jpg } } pass specular { texture_unit specMap { texture GreenSkin.jpg } } } } material Ogre/Eyes : CelShading { technique { set $diffuse "1 0.7 0 1" set $specular "1 0.8 0 1" set $edge "0 0 0 0" } } material Ogre/Tusks : CelShading { technique { set $diffuse "0.7 0.7 0.6 1" set $specular "0 0 0 1" set $edge "0.4 0.4 0.3 1" pass decal { texture_unit decalmap { texture tusk.jpg } } } } material Ogre/Earring : CelShading { technique { set $diffuse "0.7 0.7 0 1" set $specular "1 1 1 1" set $edge "0.6 0.6 0 1" } }