Transparency Shader API

To properly handle transparency, your fragment shader should contains the following function calls: More...

Functions
bool	OivDepthPeel (vec3 fragmentCoords)
	This method peels the current fragment.
void	OivDepthPeelingOutputColor (vec4 color)
	When depth peeling is enabled, OivDepthPeelingOutputColor must be called instead of setting 'gl_FragColor' since some depth peeling techniques use MRTs (multiple render targets) or premultiply the color by the alpha value (on-the-fly blending for example).
void	OivDepthPeelingOutputColor (vec4 color, vec3 coords)
	By default the depth generated by the rasterizer (gl_FragCoord.z) is used, but some algorithms may modify the depth in the fragment shader.

Detailed Description

To properly handle transparency, your fragment shader should contains the following function calls:

• You should enclose your code in if ( OivDepthPeel(gl_FragCoord.xyz) ) { } condition
• You should output your color using OivDepthPeelingOutputColor() method

These methods are accessible by including the <Inventor/oivDepthPeeling_frag.h> header in your shader: Ex:

 
void main()
{
  if ( OivDepthPeel(gl_FragCoord.xyz) )
  {
    Vec4 color = vec4(1, 0, 0, 0.5);
    OivDepthPeelingOutputColor(color);
  }
}

Function Documentation

OivDepthPeel()

bool OivDepthPeel

(

vec3

fragmentCoords

)

This method peels the current fragment.

If the fragment must be ignored, this method does the discard. The fragment coords must be in screen space (gl_FragCoord.xyz should always be used)

Returns true if the fragment should be shaded.

OivDepthPeelingOutputColor() [1/2]

void OivDepthPeelingOutputColor

(

vec4

color

)

When depth peeling is enabled, OivDepthPeelingOutputColor must be called instead of setting 'gl_FragColor' since some depth peeling techniques use MRTs (multiple render targets) or premultiply the color by the alpha value (on-the-fly blending for example).

OivDepthPeelingOutputColor() [2/2]

void OivDepthPeelingOutputColor	(	vec4	color,
		vec3	coords
	)

By default the depth generated by the rasterizer (gl_FragCoord.z) is used, but some algorithms may modify the depth in the fragment shader.

In these cases gl_FragCoord.z is not valid and the user-defined depth coordinate must be explicitly specified in the 'coords' parameter.