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Public Member Functions | Static Public Member Functions | Public Attributes | Protected Member Functions
SoShaderProgram Class Reference

The SoShaderProgram class is used to specify a set of vertex/geometry/fragment objects. More...

#include <Inventor/nodes/SoShaderProgram.h>

Inheritance diagram for SoShaderProgram:
SoNode SoFieldContainer SoBase

List of all members.

Public Member Functions

 SoShaderProgram (void)
void setEnableCallback (SoShaderProgramEnableCB *cb, void *closure)
virtual void GLRender (SoGLRenderAction *action)
virtual void search (SoSearchAction *action)

Static Public Member Functions

static void initClass ()

Public Attributes

SoMFNode shaderObject

Protected Member Functions

virtual ~SoShaderProgram ()

Detailed Description

The SoShaderProgram class is used to specify a set of vertex/geometry/fragment objects.

This node can store one of each of SoVertexShader, SoGeometryShader and SoFragmentShader in its shaderObject field. Coin will load all shader objects specified there, and attach all objects into a program before binding it as the current shader program.

A typical scene graph with shaders will look something like this:

  Separator {
    ShaderProgram {
      shaderObject [
        VertexShader {
          sourceProgram "myvertexshader.glsl"
          parameter [
            ShaderParameter1f { name "myvertexparam" value 1.0 }
          ]
        }
        FragmentShader {
          sourceProgram "myfragmentshader.glsl"
          parameter [
            ShaderParameter1f { name "myfragmentparam" value 2.0 }
          ]
        }
      ]
    }
    Cube { }
  }

This will render the Cube with the vertex and fragment shaders specified in myvertexshader.glsl and myfragmentshader.glsl. Coin also supports ARB shaders and Cg shaders (if the Cg library is installed). However, we recommend using GLSL since we will focus mostly on support this shader language.

Coin defines some named parameters that can be added by the application programmer, and which will be automatically updated by Coin while traversing the scene graph.

Example scene graph that renders per-fragment OpenGL Phong lighting for one light source. The shaders assume the first light source is a directional light. This is the case if you open the file in a standard examiner viewer.

The iv-file:

  Separator {
    ShaderProgram {
      shaderObject [
        VertexShader {
          sourceProgram "perpixel_vertex.glsl"
        }
        FragmentShader {
          sourceProgram "perpixel_fragment.glsl"
        }
      ]
    }
    Complexity { value 1.0 }
    Material { diffuseColor 1 0 0 specularColor 1 1 1 shininess 0.9 }
    Sphere { }

    Translation { translation 3 0 0 }
    Material { diffuseColor 0 1 0 specularColor 1 1 1 shininess 0.9 }
    Cone { }

    Translation { translation 3 0 0 }
    Material { diffuseColor 0.8 0.4 0.1 specularColor 1 1 1 shininess 0.9 }
    Cylinder { }
  }

The vertex shader (perpixel_vertex.glsl):

  varying vec3 ecPosition3;
  varying vec3 fragmentNormal;

  void main(void)
  {
    vec4 ecPosition = gl_ModelViewMatrix * gl_Vertex;
    ecPosition3 = ecPosition.xyz / ecPosition.w;
    fragmentNormal = normalize(gl_NormalMatrix * gl_Normal);

    gl_Position = ftransform();
    gl_FrontColor = gl_Color;
  }

The fragment shader (perpixel_vertex.glsl):

  varying vec3 ecPosition3;
  varying vec3 fragmentNormal;

  void DirectionalLight(in int i,
                        in vec3 normal,
                        inout vec4 ambient,
                        inout vec4 diffuse,
                        inout vec4 specular)
  {
    float nDotVP; // normal . light direction
    float nDotHV; // normal . light half vector
    float pf;     // power factor

    nDotVP = max(0.0, dot(normal, normalize(vec3(gl_LightSource[i].position))));
    nDotHV = max(0.0, dot(normal, vec3(gl_LightSource[i].halfVector)));

    if (nDotVP == 0.0)
      pf = 0.0;
    else
      pf = pow(nDotHV, gl_FrontMaterial.shininess);

    ambient += gl_LightSource[i].ambient;
    diffuse += gl_LightSource[i].diffuse * nDotVP;
    specular += gl_LightSource[i].specular * pf;
  }

  void main(void)
  {
    vec3 eye = -normalize(ecPosition3);
    vec4 ambient = vec4(0.0);
    vec4 diffuse = vec4(0.0);
    vec4 specular = vec4(0.0);
    vec3 color;

    DirectionalLight(0, normalize(fragmentNormal), ambient, diffuse, specular);

    color =
      gl_FrontLightModelProduct.sceneColor.rgb +
      ambient.rgb * gl_FrontMaterial.ambient.rgb +
      diffuse.rgb * gl_Color.rgb +
      specular.rgb * gl_FrontMaterial.specular.rgb;

    gl_FragColor = vec4(color, gl_Color.a);
  }

FILE FORMAT/DEFAULTS:

    ShaderProgram {
      shaderObject []
    }
See also:
SoShaderObject
SoShaderProgram
Since:
Coin 2.5

Constructor & Destructor Documentation

SoShaderProgram::SoShaderProgram ( void  )

Constructor.

SoShaderProgram::~SoShaderProgram ( ) [protected, virtual]

Destructor.


Member Function Documentation

void SoShaderProgram::setEnableCallback ( SoShaderProgramEnableCB *  cb,
void *  closure 
)

Adds a callback which is called every time this program is enabled/disabled.

void SoShaderProgram::GLRender ( SoGLRenderAction action) [virtual]

Action method for the SoGLRenderAction.

This is called during rendering traversals. Nodes influencing the rendering state in any way or who wants to throw geometry primitives at OpenGL overrides this method.

Reimplemented from SoNode.

void SoShaderProgram::search ( SoSearchAction action) [virtual]

Action method for SoSearchAction.

Compares the search criteria from the action to see if this node is a match. Searching is done by matching up all criteria set up in the SoSearchAction -- if any of the requested criteria is a miss, the search is not deemed successful for the node.

See also:
SoSearchAction

Reimplemented from SoNode.

void SoShaderProgram::initClass ( void  ) [static]

Sets up initialization for data common to all instances of this class, like submitting necessary information to the Coin type system.

Reimplemented from SoNode.


Member Data Documentation

The shader objects.


The documentation for this class was generated from the following files:

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Generated on Thu Apr 28 2011 03:43:32 for Coin by Doxygen 1.7.4.