General


This is a shader that does the following:

  • diffuse mapping (-RGB diffuse map)
  • specular mapping (RGB specular map)
  • ambient occlusion mapping (RGB AO map aligned with the other maps - usually gray-scale so R, G, and B are all the same)
  • normal mapping (standard XYZ tangent-space normal map)


Lighting is done per-light (1 ambient pass and 1 pass for every light) mostly per-pixel. It is not the most efficient thing around, but depending on what you need it for, it might be good enough. It supports spotlights, point lights, and directional lights. Works flawlessly with additive/modulative stencil shadows (and can easily be modified for integrated shadow mapping).

License: none. I'm putting this in the public domain, so do whatever you want with it. If you end up modifying it to do something really useful, it'd be nice if you decide to update this page. Of course, this is not required.

Showing the shader in action...
Showing the shader in action...

white.png

You can't really see it, it is a completely white texture → White.png

flat_n.png

A flat normal map, values of 127, 127, 255 everywhere → Flat_n.png

general.cg

struct VIn
{
    float4 p    : POSITION;
    float3 n    : NORMAL;
    float3 t    : TANGENT;
    float2 uv   : TEXCOORD0;
};

struct VOut
{
    float4 p    : POSITION;

    float2 uv   : TEXCOORD0;
    float4 wp   : TEXCOORD1;
    float3 n    : TEXCOORD2;
    float3 t    : TEXCOORD3;
    float3 b    : TEXCOORD4;
    float4 lp   : TEXCOORD5;
    float3 sdir : TEXCOORD6;
};

struct PIn
{
    float2 uv   : TEXCOORD0;
    float4 wp   : TEXCOORD1;
    float3 n    : TEXCOORD2;
    float3 t    : TEXCOORD3;
    float3 b    : TEXCOORD4;
    float4 lp   : TEXCOORD5;
    float3 sdir : TEXCOORD6;
};

void ambient_vs(VIn IN,
    uniform float4x4 wvpMat,
    out float4 oPos : POSITION,
    out float2 oUV : TEXCOORD0)
{
    oPos = mul(wvpMat, IN.p);
    oUV = IN.uv;
}

float4 ambient_ps(in float2 uv : TEXCOORD0,
    uniform float3 ambient,
    uniform float4 matDif,
    uniform sampler2D dMap,
    uniform sampler2D aoMap): COLOR0
{
    return tex2D(dMap, uv) * tex2D(aoMap, uv) *
        float4(ambient, 1) * float4(matDif.rgb, 1);
}

VOut diffuse_vs(VIn IN,
    uniform float4x4 wMat,
    uniform float4x4 wvpMat,
    uniform float4x4 tvpMat,
    uniform float4 spotlightDir)
{
    VOut OUT;
    OUT.wp = mul(wMat, IN.p);
    OUT.p = mul(wvpMat, IN.p);

    OUT.uv = IN.uv;

    OUT.n = IN.n;
    OUT.t = IN.t;
    OUT.b = cross(IN.t, IN.n);
    OUT.sdir = mul(wMat, spotlightDir).xyz; // spotlight dir in world space

    OUT.lp = mul(tvpMat, OUT.wp);

    return OUT;
}

float4 diffuse_ps(
    PIn IN,
    uniform float3 lightDif0,
    uniform float4 lightPos0,
    uniform float4 lightAtt0,
    uniform float3 lightSpec0,
    uniform float4 matDif,
    uniform float4 matSpec,
    uniform float matShininess,
    uniform float3 camPos,
    uniform float4 invSMSize,
    uniform float4 spotlightParams,
    uniform float4x4 iTWMat,
    uniform sampler2D diffuseMap : TEXUNIT0,
    uniform sampler2D specMap : TEXUNIT1,
    uniform sampler2D normalMap : TEXUNIT2): COLOR0
{
    // direction
    float3 ld0 = normalize(lightPos0.xyz - (lightPos0.w * IN.wp.xyz));

    half lightDist = length(lightPos0.xyz - IN.wp.xyz) / lightAtt0.r;
    // attenuation
    half ila = lightDist * lightDist; // quadratic falloff
    half la = 1.0 - ila;

    float4 normalTex = tex2D(normalMap, IN.uv);

    float3x3 tbn = float3x3(IN.t, IN.b, IN.n);
    float3 normal = mul(transpose(tbn), normalTex.xyz * 2 - 1); // to object space
    normal = normalize(mul((float3x3)iTWMat, normal));

    float3 diffuse = max(dot(ld0, normal), 0);

    // calculate the spotlight effect
    float spot = (spotlightParams.x == 1 &&
        spotlightParams.y == 0 &&
        spotlightParams.z == 0 &&
        spotlightParams.w == 1 ? 1 : // if so, then it's not a spot light
        saturate(
            (dot(ld0, normalize(-IN.sdir)) - spotlightParams.y) /
            (spotlightParams.x - spotlightParams.y)));

    float3 camDir = normalize(camPos - IN.wp.xyz);
    float3 halfVec = normalize(ld0 + camDir);
    float3 specular = pow(max(dot(normal, halfVec), 0), matShininess);

    float4 diffuseTex = tex2D(diffuseMap, IN.uv);
    float4 specTex = tex2D(specMap, IN.uv);

    float3 diffuseContrib = (diffuse * lightDif0 * diffuseTex.rgb * matDif.rgb);
    float3 specularContrib = (specular * lightSpec0 * specTex.rgb * matSpec.rgb);
    float3 light0C = (diffuseContrib + specularContrib) * la * spot;

    return float4(light0C, diffuseTex.a);
}

general.material

material base_material
{
    set $diffuseCol "1 1 1 1"
    set $specularCol "1 1 1"
    set $shininess "32"

    technique
    {
        pass
        {
            illumination_stage ambient

            ambient 1 1 1 1
            diffuse $diffuseCol
            specular 0 0 0 0
            emissive 0 0 0 0

            vertex_program_ref ambient_vs
            {
            }

            fragment_program_ref ambient_ps
            {
            }

            texture_unit diffuseMap
            {
                texture white.png
            }

            texture_unit aoMap
            {
                texture white.png
            }
        }

        pass
        {
            illumination_stage per_light

            scene_blend add
//            iteration once_per_light   not needed while   illumination_stage per_light   is used

            vertex_program_ref diffuse_vs
            {
            }

            fragment_program_ref diffuse_ps
            {
            }

            diffuse $diffuseCol
            specular $specularCol $shininess
            ambient 0 0 0 0

            texture_unit diffuseMap
            {
                texture white.png
            }

            texture_unit specMap
            {
                texture white.png
            }

            texture_unit normalMap
            {
                texture flat_n.png
            }
        }
    }
}

// examples (require the appropriate [[textures]], all found in the Ogre samples)

material rockwall : base_material
{
    set_texture_alias diffuseMap rockwall.tga
    set_texture_alias specMap rockwall.tga
    set_texture_alias normalMap rockwall_NH.tga
}

material metal : base_material
{
    set_texture_alias diffuseMap RustedMetal.jpg
    set_texture_alias specMap RustedMetal.jpg
}

material ogre : base_material
{
    set_texture_alias diffuseMap GreenSkin.jpg
    set_texture_alias specMap GreenSkin.jpg
    set_texture_alias normalMap NMHollyBumps.png
}

general.program

vertex_program diffuse_vs cg
{
    source general.cg
    profiles vs_1_1 arbvp1
    entry_point diffuse_vs

    default_params
    {
        param_named_auto wMat world_matrix
        param_named_auto wvpMat worldviewproj_matrix
        param_named_auto tvpMat texture_viewproj_matrix 0
        param_named_auto spotlightDir light_direction_object_space 0
    }
}

vertex_program ambient_vs cg
{
    source general.cg
    profiles vs_1_1 arbvp1
    entry_point ambient_vs

    default_params
    {
        param_named_auto wvpMat worldviewproj_matrix
    }
}

fragment_program ambient_ps cg
{
    source general.cg
    profiles ps_2_0 arbfp1
    entry_point ambient_ps

    default_params
    {
        param_named_auto ambient ambient_light_colour
        param_named_auto matDif surface_diffuse_colour
    }
}

fragment_program diffuse_ps cg
{
    source general.cg
    profiles ps_2_x arbfp1
    entry_point diffuse_ps

    default_params
    {
        param_named_auto lightDif0 light_diffuse_colour 0
        param_named_auto lightSpec0 light_specular_colour 0
        param_named_auto camPos camera_position
        param_named_auto matShininess surface_shininess
        param_named_auto matDif surface_diffuse_colour
        param_named_auto matSpec surface_specular_colour
        param_named_auto lightPos0 light_position 0
        param_named_auto lightAtt0 light_attenuation 0
        param_named_auto iTWMat inverse_transpose_world_matrix
        param_named_auto spotlightParams spotlight_params 0
    }
}

Configurables

The shader has several configurables:

material some_material : base_material
{
    // any of these maps can be left out if you don't have one
    set_texture_alias diffuseMap some_dif.png
    set_texture_alias specMap some_spec.png
    set_texture_alias normalMap some_norm.png
    set_texture_alias aoMap some_ao.png

    // diffuse colour multiplier (for example, green-ish)
    set $diffuseCol "0.1 1 0.1"
    // specular colour multiplier (for example, red-ish)
    set $specularCol "1 0.1 0.1"
    // specular power (shininess) (the higher, the sharper the highlights)
    set $shininess "128"

    // once again, you can leave any of these configurables out if you don't need them
}

Support for mirrored UVs

If you have a symmetrical object and decided to split it in two for more uv space, you probably noticed that the shader above displays the mirrored half inverted. Here is what you have to do so you can fix this:

  • Export your mesh with parity stored in w (in ogre max for 3D Studio Max this option is under Object Settings/Mesh tab/Store parity in W) (Also remember to export tangents as well by setting Generate Tangents to yes)
  • Modify general.cg so that the tangent is stored in a float4 like this:


from this

struct VIn
{
    float4 p    : POSITION;
    float3 n    : NORMAL;
    float3 t    : TANGENT;
    float2 uv   : TEXCOORD0;
};


to this

struct VIn
{
    float4 p    : POSITION;
    float3 n    : NORMAL;
    float4 t    : TANGENT; // <- this was changed
    float2 uv   : TEXCOORD0;
};


and now the output structure from this

struct VOut
{
    float4 p    : POSITION;

    float2 uv   : TEXCOORD0;
    float4 wp   : TEXCOORD1;
    float3 n    : TEXCOORD2;
    float3 t    : TEXCOORD3;
    float3 b    : TEXCOORD4;
    float4 lp   : TEXCOORD5;
    float3 sdir : TEXCOORD6;
};


to this

struct VOut
{
    float4 p    : POSITION;

    float2 uv   : TEXCOORD0;
    float4 wp   : TEXCOORD1;
    float3 n    : TEXCOORD2;
    float4 t    : TEXCOORD3; //<- this was changed
    float3 b    : TEXCOORD4;
    float4 lp   : TEXCOORD5;
    float3 sdir : TEXCOORD6;
};


now we only have to change the vertex program from this

VOut diffuse_vs(VIn IN,
    uniform float4x4 wMat,
    uniform float4x4 wvpMat,
    uniform float4x4 tvpMat,
    uniform float4 spotlightDir)
{
    VOut OUT;
    OUT.wp = mul(wMat, IN.p);
    OUT.p = mul(wvpMat, IN.p);

    OUT.uv = IN.uv;

    OUT.n = IN.n;
    OUT.t = IN.t;
    OUT.b = cross(IN.t, IN.n);
    OUT.sdir = mul(wMat, spotlightDir).xyz; // spotlight dir in world space

    OUT.lp = mul(tvpMat, OUT.wp);

    return OUT;
}


to this

VOut diffuse_vs(VIn IN,
    uniform float4x4 wMat,
    uniform float4x4 wvpMat,
    uniform float4x4 tvpMat,
    uniform float4 spotlightDir)
{
    VOut OUT;
    OUT.wp = mul(wMat, IN.p);
    OUT.p = mul(wvpMat, IN.p);

    OUT.uv = IN.uv;

    OUT.n = IN.n;
    OUT.t = IN.t;
    OUT.b = cross(IN.t.xyz, IN.n) * IN.t.w; //<-this was changed
    OUT.sdir = mul(wMat, spotlightDir).xyz; // spotlight dir in world space

    OUT.lp = mul(tvpMat, OUT.wp);

    return OUT;
}

  • and you are done.


Alias: Normal_AO_Specular_Mapping_Shader

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