public abstract class SoShaderObject extends SoNode
SoVertexShader
), a geometry shader (SoGeometryShader
), a fragment shader (SoFragmentShader
), a tessellation control shader (SoTessellationControlShader
) or a tessellation evaluation shader (SoTessellationEvaluationShader
) program. (Tessellation shaders are supported since Open Inventor 9.3)
There are five types of shaders that may be executed (in this order) in the rendering pipeline. Any one or all of these stages may be replaced by an application defined shader program.
Shader object nodes cannot be inserted directly in a scene graph. They must be added to the
shaderObject field of an SoShaderProgram
node.
A shader object is defined by the following properties:
sourceProgram
field),
parameter
field),
isActive
field).
The source program can be specified either by a string containing the program source code, or by a filename which contains the program source code. How the sourceProgram field is interpreted depends on the field sourceType
. The shading languages accepted for the source program are OpenGL Shader Language (GLSL) , Cg from NVIDIA (see NOTE 1) and assembly language ( ARB_vertex_program, ARB_fragment_program). Generally GLSL is recommended because it works on any OpenGL hardware and is much higher level than the ARB commands.
Uniform parameters can be set through the parameter
field. Uniform means, in the case of a vertex or geometry program, a value which is the same for all vertices in a primitive, and, in the case of a fragment program, a value which is the same for all fragments created by a primitive. Each uniform parameter is represented by an instance of a specific subclass of SoUniformShaderParameter
. For example, an SoShaderParameter1i
holds a single integer value. A uniform parameter has no effect if it is not valid, that is, if there is no corresponding name (identifier) in the CG/GLSL (ARB) source program. See NOTE 2 for info on retrieving a texture sampler uniform parameter within a GLSL program, an NVIDIA Cg fragment program, or an ARB_vertex_program/ARB_fragment_program program.
A vertex shader can also use
vertex parameters, which are per-vertex data passed from the application to the vertex shader. Vertex parameters are represented by an instance of a specific subclass of SoVertexShaderParameter
. For example, an SoVertexShaderParameter1f
holds a set of floating point values and an SoVertexShaderParameter3f
holds a set of SbVec3f
values. Vertex parameter nodes are property nodes (similar to materials or normals) and should be added directly in the scene graph, not in the shader object.
Tips:
SoShaderParameter
parameter.
void main(// Inputs Input IN, uniform sampler2D rampDiffuse, // Texture sampler 2D of the texture unit 0 uniform sampler2D rampSpecular, // Texture sampler 2D of the texture unit 1 uniform sampler2D rampEdge, // Texture sampler 2D of the texture unit 2 ...
SoShaderParameter1i
must used for each texture sampler in order to specify the texture unit and texture sampler uniform parameter name pair.
NOTE 3: With Cg and ARB languages, at least the ARB_vertex_program and ARB_fragment_program, and with GLSL, at least GL_ARB_vertex_shader, GL_ARB_fragment_shader, and GL_ARB_shader_objects OpenGL extensions must be supported by your graphics board in order to be able to define a vertex shader and a fragment shader respectively. Otherwise no shader program will be executed.
NOTE 4: You should keep in mind that vertex and fragment programs modify the standard OpenGL pipeline.
File format/default:
This is an abstract class. See the reference page of a derived class for the format and default values.
Simple fragment shader with one uniform parameter:
// Simple fragment shader with one uniform parameter // First load the fragment shader code SoFragmentShader fragmentShader = new SoFragmentShader(); fragmentShader.sourceProgram.setValue( "filename.glsl" ); // Set the shader parameter SoShaderParameter1i parameter = new SoShaderParameter1i(); parameter.name.setValue( "data1" ); parameter.value.setValue( 1 ); fragmentShader.parameter.set1Value( 0, parameter ); // Associate fragment shader with a shader program node SoShaderProgram shaderProgram = new SoShaderProgram(); shaderProgram.shaderObject.set1Value( 0, fragmentShader ); root.addChild(shaderProgram);
See also:
SoVertexShader
, SoGeometryShader
, SoFragmentShader
, SoShaderProgram
, SoShaderParameter
, SoUniformShaderParameter
, SoVertexShaderParameter
, SoTessellationControlShader
, SoTessellationEvaluationShader
Modifier and Type | Class and Description |
---|---|
static class |
SoShaderObject.ShaderTypes
Type of the shader.
|
static class |
SoShaderObject.SourceTypes
Shader Object source type possible values.
|
SoNode.RenderModes
Inventor.ConstructorCommand
Modifier and Type | Field and Description |
---|---|
SoSFBool |
isActive
Specifies if the shader object is active or not.
|
SoMFUniformShaderParameter |
parameter
Contains the shader's uniform parameters.
|
SoSFFilePathString |
sourceProgram
Contains the shader object's source program, specified by a filename (
sourceType set to FILENAME ) or by the string containing the program (sourceType set to ARB_PROGRAM , CG_PROGRAM , or GLSL_PROGRAM ). |
SoSFEnum<SoShaderObject.SourceTypes> |
sourceType
Specifies the shader object's source type.
|
VERBOSE_LEVEL, ZeroHandle
Modifier and Type | Method and Description |
---|---|
SoShaderObject.ShaderTypes |
getShaderType()
Must be redefined by derived class.
|
affectsState, callback, copy, copy, distribute, doAction, getAlternateRep, getBoundingBox, getByName, getMatrix, getPrimitiveCount, getRenderEngineMode, getRenderUnitID, GLRender, GLRenderBelowPath, GLRenderInPath, GLRenderOffPath, grabEventsCleanup, grabEventsSetup, handleEvent, isBoundingBoxIgnoring, isOverride, pick, rayPick, search, setOverride, touch, write
copyFieldValues, copyFieldValues, enableNotify, fieldsAreEqual, get, getAllFields, getEventIn, getEventOut, getField, getFieldName, hasDefaultValues, isNotifyEnabled, set, setToDefaults
dispose, getName, isDisposable, isSynchronizable, setName, setSynchronizable
getNativeResourceHandle
public final SoSFBool isActive
public final SoSFEnum<SoShaderObject.SourceTypes> sourceType
FILENAME
), or a string containing the source program (ARB_PROGRAM
, CG_PROGRAM
, or GLSL_PROGRAM
). Use enum SourceType
. Defaule is FILENAME.
NOTE: The source type must be specified before the source program (sourceProgram
) is specified.
public final SoSFFilePathString sourceProgram
sourceType
set to FILENAME
) or by the string containing the program (sourceType
set to ARB_PROGRAM
, CG_PROGRAM
, or GLSL_PROGRAM
).
If the filename is not an absolute path name, the list of directories maintained by SoInput
is searched. If the source program is not found in any of those directories, then the file is searched for relative to the directory from which the SoShaderObject
node was read.
NOTE: The source type (sourceType
) must be specified before the source program is specified.
public final SoMFUniformShaderParameter parameter
public SoShaderObject.ShaderTypes getShaderType()
Generated on July 31, 2019, Copyright © Thermo Fisher Scientific. All rights reserved. http://www.openinventor.com