[861] | 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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