1 | /* Bump mapping with Parallax offset vertex program
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2 | In this program, we want to calculate the tangent space light end eye vectors
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3 | which will get passed to the fragment program to produce the per-pixel bump map
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4 | with parallax offset effect.
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5 | */
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6 |
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7 | /* Vertex program that moves light and eye vectors into texture tangent space at vertex */
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8 |
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9 | void main_vp(float4 position : POSITION,
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10 | float3 normal : NORMAL,
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11 | float2 uv : TEXCOORD0,
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12 | float3 tangent : TEXCOORD1,
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13 | // outputs
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14 | out float4 oPosition : POSITION,
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15 | out float2 oUv : TEXCOORD0,
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16 | out float3 oLightDir : TEXCOORD1, // tangent space
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17 | out float3 oEyeDir : TEXCOORD2, // tangent space
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18 | out float3 oHalfAngle : TEXCOORD3, //
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19 | // parameters
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20 | uniform float4 lightPosition, // object space
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21 | uniform float3 eyePosition, // object space
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22 | uniform float4x4 worldViewProj)
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23 | {
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24 | // calculate output position
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25 | oPosition = mul(worldViewProj, position);
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26 |
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27 | // pass the main uvs straight through unchanged
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28 | oUv = uv;
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29 |
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30 | // calculate tangent space light vector
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31 | // Get object space light direction
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32 | float3 lightDir = normalize(lightPosition.xyz - (position * lightPosition.w));
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33 | float3 eyeDir = eyePosition - position.xyz;
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34 |
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35 | // Calculate the binormal (NB we assume both normal and tangent are
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36 | // already normalised)
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37 | // NB looks like nvidia cross params are BACKWARDS to what you'd expect
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38 | // this equates to NxT, not TxN
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39 | float3 binormal = cross(tangent, normal);
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40 |
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41 | // Form a rotation matrix out of the vectors
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42 | float3x3 rotation = float3x3(tangent, binormal, normal);
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43 |
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44 | // Transform the light vector according to this matrix
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45 | lightDir = normalize(mul(rotation, lightDir));
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46 | eyeDir = normalize(mul(rotation, eyeDir));
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47 |
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48 | oLightDir = lightDir;
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49 | oEyeDir = eyeDir;
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50 | oHalfAngle = normalize(eyeDir + lightDir);
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51 | }
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52 |
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53 | // General functions
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54 |
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55 | // Expand a range-compressed vector
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56 | float3 expand(float3 v)
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57 | {
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58 | return (v - 0.5) * 2;
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59 | }
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60 |
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61 | void main_fp(float2 uv : TEXCOORD0,
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62 | float3 lightDir : TEXCOORD1,
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63 | float3 eyeDir : TEXCOORD2,
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64 | float3 halfAngle : TEXCOORD3,
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65 | uniform float3 lightDiffuse,
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66 | uniform float3 lightSpecular,
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67 | uniform float4 scaleBias,
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68 | uniform sampler2D normalHeightMap,
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69 | uniform sampler2D diffuseMap,
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70 | out float4 oColor : COLOR)
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71 | {
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72 | // get the height using the tex coords
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73 | float height = tex2D(normalHeightMap, uv).a;
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74 |
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75 | // scale and bias factors
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76 | float scale = scaleBias.x;
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77 | float bias = scaleBias.y;
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78 |
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79 | // calculate displacement
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80 | float displacement = (height * scale) + bias;
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81 |
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82 | float3 uv2 = float3(uv, 1);
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83 |
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84 | // calculate the new tex coord to use for normal and diffuse
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85 | float2 newTexCoord = ((eyeDir * displacement) + uv2).xy;
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86 |
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87 | // get the new normal and diffuse values
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88 | float3 normal = expand(tex2D(normalHeightMap, newTexCoord).xyz);
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89 | float3 diffuse = tex2D(diffuseMap, newTexCoord).xyz;
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90 |
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91 | float3 specular = pow(saturate(dot(normal, halfAngle)), 32) * lightSpecular;
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92 | float3 col = diffuse * saturate(dot(normal, lightDir)) * lightDiffuse + specular;
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93 |
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94 | oColor = float4(col, 1);
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95 | }
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