SoShaderProgram(3)

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

SYNOPSIS

#include <Inventor/nodes/SoShaderProgram.h>

Inherits SoNode.

  Public Member Functions
virtual SoType getTypeId (void) const
SoShaderProgram (void)
void setEnableCallback (SoShaderProgramEnableCB *cb, void *closure)
virtual void GLRender (SoGLRenderAction *action)
virtual void search (SoSearchAction *action)

  Static Public Member Functions
static SoType getClassTypeId (void)
static void initClass ()

  Public Attributes
SoMFNode shaderObject

  Protected Member Functions
virtual const SoFieldData * getFieldData (void) const
virtual ~SoShaderProgram ()

  Static Protected Member Functions
static const SoFieldData ** getFieldDataPtr (void)

  Additional Inherited Members

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.

•   coin_texunit[n]_model - Set to 0 when texturing is disabled, and to SoTextureImageElement::Model if there's a current texture on the state for unit n.
•   coin_light_model - Set to 1 for PHONG, 0 for BASE_COLOR lighting.
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

  SoType SoShaderProgram::getTypeId (void) const [virtual]
Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and 'downward' casting.
Usage example:
void foo(SoNode * node)
{
  if (node->getTypeId() == SoFile::getClassTypeId()) {
    SoFile * filenode = (SoFile *)node;  // safe downward cast, knows the type
  }
}
For application programmers wanting to extend the library with new nodes, engines, nodekits, draggers or others: this method needs to be overridden in all subclasses. This is typically done as part of setting up the full type system for extension classes, which is usually accomplished by using the pre-defined macros available through for instance Inventor/nodes/SoSubNode.h (SO_NODE_INIT_CLASS and SO_NODE_CONSTRUCTOR for node classes), Inventor/engines/SoSubEngine.h (for engine classes) and so on.
For more information on writing Coin extensions, see the class documentation of the toplevel superclasses for the various class groups.
Implements SoBase.

  const SoFieldData * SoShaderProgram::getFieldData (void) const [protected], [virtual]
Returns a pointer to the class-wide field data storage object for this instance. If no fields are present, returns NULL.
Reimplemented from SoFieldContainer.

  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.

Member Data Documentation

  SoMFNode SoShaderProgram::shaderObject
The shader objects.

Author
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