- Description
MGLFunctionTable is a utility class which provides wrappers for the basic
functions in the OpenGL API. Core functions up to OpenGL 2.0 are provided here, as well as a number
of ARB/EXT and vendor specific extensions. Refer to the MGLExtension
enumeration for extensions which are checked. Please refer to an OpenGL reference for usage of the OpenGL functions
provided in this wrapper class. When using the functions provided, the standard GL* type and constant
definitions to be used can be found in MGLDefinitions.h.MGLDefinitions.h basically provides a wrapper for what would
normally be found in gl.h and glext.h files.The naming convention used in this file is to take the regular GL*
definitions and add a "M" prefix. This is to avoid conflicts with existing
type and constant declarations which may be found in files such as gl.h and
glext.h. It is recommended that externally provided files
which have GL definitions not be included in the same C++ file to avoid
conflicts. Mixing GL code wusing MGLFunctionTable and external
code is possible, just not recommended.MGLFunctionTable cannot be created on it's own, and must
be retrieved via a method on the MHardwareRenderer class. It is possible
that this class will not be available, if the hardware renderer class
cannot be instantiated. This would be due to insufficient graphics
hardware support.Below is an example of initializing and using the function table to draw a simple 3-line axis.
Note the usage of the definitions from MGLDefinitions such as MGL_LIGHTING versus GL_LIGHTING,
and MGL_LINES and MGL_DEPTH_TEST.
class myClass
{
public:
MStatus initializeGL();
void drawAxis();
protected:
MGLFunctionTable *gGLFT; // Function table to use
private:
// No private members
};
MStatus
myClass::initializeGL()
{
// Get a pointer to a GL function table
MHardwareRenderer *rend = MHardwareRenderer::theRenderer();
if (rend)
gGLFT = rend->glFunctionTable();
if (!gGLFT)
return MStatus::kFailure;
return MStatus::kSuccess;
}
void
myClass::drawAxis()
{
// Draw a world space axis
//
gGLFT->glDisable(MGL_LIGHTING);
gGLFT->glBegin(MGL_LINES);
gGLFT->glColor3f( 1.0f, 0.0f, 0.0f );
gGLFT->glVertex3f( 0.0f, 0.0f, 0.0f );
gGLFT->glVertex3f( 3.0f, 0.0f, 0.0f );
gGLFT->glColor3f( 0.0f, 1.0f, 0.0f );
gGLFT->glVertex3f( 0.0f, 0.0f, 0.0f );
gGLFT->glVertex3f( 0.0f, 3.0f, 0.0f );
gGLFT->glColor3f( 0.0f, 0.0f, 1.0f );
gGLFT->glVertex3f( 0.0f, 0.0f, 0.0f );
gGLFT->glVertex3f( 0.0f, 0.0f, 3.0f );
gGLFT->glEnd();
gGLFT->glEnable(MGL_LIGHTING);
}
Here is a similar example of using the function table in Python.
import maya.OpenMayaRender as OpenMayaRender
def initializeGL():
glRenderer = OpenMayaRender.MHardwareRenderer.theRenderer()
glFT = glRenderer.glFunctionTable()
def printMaxTextureSize():
maxTxtSize = glFT.maxTextureSize()
print maxTxtSize
def drawAxis():
glFT.glDisable(OpenMayaRender.MGL_LIGHTING)
glFT.glBegin(OpenMayaRender.MGL_LINES)
glFT.glColor3f( 1.0, 0.0, 0.0 )
glFT.glVertex3f( 0.0, 0.0, 0.0 )
glFT.glVertex3f( 3.0, 0.0, 0.0 )
glFT.glColor3f( 0.0, 1.0, 0.0 )
glFT.glVertex3f( 0.0, 0.0, 0.0 )
glFT.glVertex3f( 0.0, 3.0, 0.0 )
glFT.glColor3f( 0.0, 0.0, 1.0 )
glFT.glVertex3f( 0.0, 0.0, 0.0 )
glFT.glVertex3f( 0.0, 0.0, 3.0 )
glFT.glEnd()
glFT.glEnable(OpenMayaRender.MGL_LIGHTING)
- Functions
- bool MGLFunctionTable:: extensionExists (MGLExtension extension)
Description Provides information as to whether a given OpenGL extension exists. That is,
the extension is reported to be supported. Arguments
- extension Extension enumeration.
Return Value
- true : if it exists. Otherwise false.
- unsigned int MGLFunctionTable:: numTexUnits () const
Description Get information about the maximum number of texture units. This may not be
the same as the number of interpolants available. Arguments Return Value
- Maximum number of texture units.
- unsigned int MGLFunctionTable:: numTexInterpolants () const
Description Get information about the maximum number of texture interpolants. Arguments Return Value
- Maximum number of texture interpolants.
- unsigned int MGLFunctionTable:: numTexImageUnits () const
Description Get information about the maximum number of texture image units available. Arguments Return Value
- Maximum number of image units.
- unsigned int MGLFunctionTable:: maxTextureSize () const
Description Get information about the maximum texture size. Arguments Return Value
- unsigned int MGLFunctionTable:: maxVertexAttributes () const
Description Get information about the maximum number of vertex attributes available. Arguments Return Value
- Number of attributes available.
enum