shaders/MarchingCubes.gs File Reference

a marching cubes geometry shader More...

Functions
vec3	getCubeCorner (int _index)
	Returns a cube's corner.
float	sampleVert (int _i)
	Samples the scalar field on a grid vertex.
int	fetchEdgeTableVal (int _i)
	Fetches a texel of the edge table texture.
int	fetchTriTableVal (int _i, int _j)
	Fetches a texel of the triangulation table texture.
vec3	vertLerp (vec3 _v0, float _s0, vec3 _v1, float _s1, float _isoLevel)
	Performs linear interpolation between two vertices using their iso values as weight.
void	main (void)
	Geometry shader entry point.
Variables
uniform isampler1D	edgeTableTex
	The edge table texture.
uniform isampler2D	triTableTex
	The triangulation table texture.
uniform sampler3D	densityTex
	The scalar field texture.
uniform int	samplingChannel
	The texture channel to sample from.
uniform vec3	marchingStep
	The marching step.
uniform float	isoLevel
	The iso level threshold.
uniform mat4	projectionMatrix
	The projection matrix generated from the Camera.
uniform mat4	ViewMatrix
	The ViewMatrix generated from the Camera.
uniform mat4	ModelMatrix
	The ModelMatrix generated from the scene transforms.
varying out vec4	position
	The calculated vertex positions (output to fragment shader).

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Detailed Description

a marching cubes geometry shader

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Function Documentation

int fetchEdgeTableVal

(

int

_i

)

Fetches a texel of the edge table texture.

Parameters:

[in]

_i

table index

int fetchTriTableVal	(	int	_i,
		int	_j
	)

Fetches a texel of the triangulation table texture.

Parameters:

[in]

_i

table index

vec3 getCubeCorner

(

int

_index

)

Returns a cube's corner.

Parameters:

[in]

_index

The corner index.

The following section is modified from :- Cyril Crassin (2007). Tutorial on implementing Marching Cubes algorithm using OpenGL API Geometry Shaders extension available at: http://www.icare3d.org/content/view/50/9/ accessed at 02/04/11

end of citation

void main

(

void

)

Geometry shader entry point.

The following section is modified from :- Cyril Crassin (2007). Tutorial on implementing Marching Cubes algorithm using OpenGL API Geometry Shaders extension available at: http://www.icare3d.org/content/view/50/9/ accessed at 02/04/11

end of citation

float sampleVert

(

int

_i

)

Samples the scalar field on a grid vertex.

Parameters:

[in]

_the

vertex index.

vec3 vertLerp	(	vec3	_v0,
		float	_s0,
		vec3	_v1,
		float	_s1,
		float	_isoLevel
	)

Performs linear interpolation between two vertices using their iso values as weight.

Parameters:

[in]	_v0	the first vertex
[in]	_s0	the first vertex iso value
[in]	_v1	the second vertex
[in]	_s1	the second vertex iso value
[in]	_isoLevel	the current iso level