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source: data/branches/Shader_HS18/programs/GLSL150/IsosurfVS.glsl @ 12181

Last change on this file since 12181 was 12115, checked in by wiesep, 6 years ago

Changed folder structure, deletet some unused files and cleaned up code

File size: 2.2 KB
Line 
1#version 150
2
3// Ogre port of Nvidia's IsoSurf.cg file
4// Modified code follows. See http://developer.download.nvidia.com/SDK/10/opengl/samples.html for original
5//
6// Cg port of Yury Uralsky's metaball FX shader
7//
8// Authors: Simon Green and Yury Urlasky
9// Email: sdkfeedback@nvidia.com
10//
11// Copyright (c) NVIDIA Corporation. All rights reserved.
12////////////////////////////////////////////////////////////////////////////////////////////////////
13
14in vec4 vertex;
15
16out VertexData {
17    vec3 N;
18    vec2 Field;
19    // vec4 Color;
20} VertexOut;
21
22uniform float IsoValue = 1.0;
23uniform mat4 WorldViewProj;
24uniform mat4 origWorldViewIT;
25uniform vec4 Metaballs[2] = vec4[](vec4( -0.5, 0, 0, 0.2 ), vec4( 0.6, 0, 0, 0.1 ));
26
27// Size of the sampling grid
28const ivec3 SizeMask = ivec3( 63, 63, 63 );
29const ivec3 SizeShift = ivec3( 0, 6, 12 );
30
31// Metaball function
32// Returns metaball function value in .w and its gradient in .xyz
33vec4 Metaball(vec3 Pos, vec3 Center, float RadiusSq)
34{
35    const float epsilon = 0.001;
36
37    vec3 Dist = Pos - Center;
38    float InvDistSq = 1 / (dot(Dist, Dist) + epsilon);
39
40    vec4 o;
41    o.xyz = -2 * RadiusSq * InvDistSq * InvDistSq * Dist;
42    o.w = RadiusSq * InvDistSq;
43    return o;
44}
45
46void main()
47{
48    vec4 Pos;
49
50    // Generate sampling point position based on its index
51    // Pos.x = float((gl_VertexID >> SizeShift.x) & SizeMask.x) / (SizeMask.x + 1);
52    // Pos.y = float((gl_VertexID >> SizeShift.y) & SizeMask.y) / (SizeMask.y + 1);
53    // Pos.z = float((gl_VertexID >> SizeShift.z) & SizeMask.z) / (SizeMask.z + 1);
54    // Pos = Pos*2 - 1;
55    Pos = vertex;
56   
57    // Sum up contributions from all metaballs
58    vec4 Field = vec4(0,0,0,0);
59    for (int i = 0; i < 2; i++)
60        Field += Metaball(Pos.xyz, Metaballs[i].xyz, Metaballs[i].w);
61
62    mat3 WorldViewIT = mat3(origWorldViewIT[0].xyz, origWorldViewIT[1].xyz, origWorldViewIT[2].xyz);
63   
64    // Transform position and normals
65    gl_Position = WorldViewProj * vec4(Pos.xyz, 1);
66    VertexOut.N = WorldViewIT * Field.xyz;        // we want normals in world space
67    VertexOut.Field.x = Field.w;
68
69    // Generate in-out flags
70    VertexOut.Field.y = (Field.w < IsoValue) ? 1 : 0;
71
72    // VertexOut.Color = (Field*0.5+0.5) * (Field.w / 10.0);
73}
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