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source: code/branches/skybox/Media/materials/programs/OffsetMapping.cg @ 1929

Last change on this file since 1929 was 390, checked in by landauf, 17 years ago

added materials

File size: 3.2 KB
Line 
1/* Bump mapping with Parallax offset vertex program
2   In this program, we want to calculate the tangent space light end eye vectors
3   which will get passed to the fragment program to produce the per-pixel bump map
4   with parallax offset effect.
5*/
6
7/* Vertex program that moves light and eye vectors into texture tangent space at vertex */
8
9void main_vp(float4 position   : POSITION,
10              float3 normal      : NORMAL,
11              float2 uv         : TEXCOORD0,
12              float3 tangent     : TANGENT0,
13              // outputs
14              out float4 oPosition    : POSITION,
15              out float2 oUv          : TEXCOORD0,
16              out float3 oLightDir    : TEXCOORD1, // tangent space
17             out float3 oEyeDir       : TEXCOORD2, // tangent space
18             out float3 oHalfAngle    : TEXCOORD3, //
19              // parameters
20              uniform float4 lightPosition, // object space
21              uniform float3 eyePosition,   // object space
22              uniform float4x4 worldViewProj)
23
24   // calculate output position
25   oPosition = mul(worldViewProj, position);
26
27   // pass the main uvs straight through unchanged
28   oUv = uv;
29
30   // calculate tangent space light vector
31   // Get object space light direction
32   float3 lightDir = normalize(lightPosition.xyz -  (position * lightPosition.w));
33   float3 eyeDir = eyePosition - position.xyz;
34   
35   // Calculate the binormal (NB we assume both normal and tangent are
36   // already normalised)
37   // NB looks like nvidia cross params are BACKWARDS to what you'd expect
38   // this equates to NxT, not TxN
39   float3 binormal = cross(tangent, normal);
40   
41   // Form a rotation matrix out of the vectors
42   float3x3 rotation = float3x3(tangent, binormal, normal);
43   
44   // Transform the light vector according to this matrix
45   lightDir = normalize(mul(rotation, lightDir));
46   eyeDir = normalize(mul(rotation, eyeDir));
47
48   oLightDir = lightDir;
49   oEyeDir = eyeDir;
50   oHalfAngle = normalize(eyeDir + lightDir);
51}
52
53// General functions
54
55// Expand a range-compressed vector
56float3 expand(float3 v)
57{
58        return (v - 0.5) * 2;
59}
60
61void main_fp(float2 uv : TEXCOORD0,
62        float3 lightDir : TEXCOORD1,
63        float3 eyeDir : TEXCOORD2,
64        float3 halfAngle : TEXCOORD3,
65        uniform float3 lightDiffuse,
66        uniform float3 lightSpecular,
67        uniform float4 scaleBias,
68        uniform sampler2D normalHeightMap,
69        uniform sampler2D diffuseMap,
70        out float4 oColor : COLOR)
71{
72        // get the height using the tex coords
73        float height = tex2D(normalHeightMap, uv).a;
74
75        // scale and bias factors       
76        float scale = scaleBias.x;
77        float bias = scaleBias.y;
78
79        // calculate displacement       
80        float displacement = (height * scale) + bias;
81       
82        float3 uv2 = float3(uv, 1);
83       
84        // calculate the new tex coord to use for normal and diffuse
85        float2 newTexCoord = ((eyeDir * displacement) + uv2).xy;
86       
87        // get the new normal and diffuse values
88        float3 normal = expand(tex2D(normalHeightMap, newTexCoord).xyz);
89        float3 diffuse = tex2D(diffuseMap, newTexCoord).xyz;
90       
91        float3 specular = pow(saturate(dot(normal, halfAngle)), 32) * lightSpecular;
92        float3 col = diffuse * saturate(dot(normal, lightDir)) * lightDiffuse + specular;
93               
94        oColor = float4(col, 1);
95}
96
97
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