GL_OBJECT_3D

Description

This object can be used to write custom OpenGL scripts for 3D rendering. The rendering script can reference any data exposed to the scripting engine.

Most OpenGL 1.1 functions and constants (as defined in the gl.h C header) are available, execpt the functions using arrays (vertex arrays etc.). Extensions and shaders are not yet available.

This element is currently *experimental* and may change in future releases.

Inherited Attributes

See Attributes Common to 3D Objects.

Specific Attributes

Name	Value Type	Default Value	Description	Comment	V.	Exp.
render_script	script	empty	OpenGL script to render the object.		2.0	No
Exposed Actions
Invalidate	ref_type_action		Requests the object to be re-rendered.		2.0	2.0

Examples

3D Shapes

Display simple 3D shapes with an OpenGL script defined in a separate file:

Skin file:

<?xml version="1.0" encoding="utf-8" ?>
<SKIN background_color="#000000" text_color="#ffffff">
    <!-- Custom 3D Viewer definition -->
    <DEFINE>
        <CUS_3D_VIEWER base_type="VIEW_3D" width="600" height="400" cursor="system::open_hand" y_ratio=".8" z_ratio=".5" transform.tz="-7" transform.ry="-45" transform.rx="-45"/>
    </DEFINE>

    <!-- Including the script file that defines the OpenGL rendering function-->
    <SCRIPT src="openGLShapes.cxx"/>

    <!-- The 3D Viewer -->
    <CUS_3D_VIEWER id="view3d">
        <!-- Custom GL scripting object, calling the glRenderShapes function defined in openGLshapes.cxx-->
        <GL_OBJECT_3D id="view3d.shapes" render_script="glRenderShapes(this.opacity)"/>
    </CUS_3D_VIEWER>

    <!-- Force the engine to expose the view3d.shapes.opacity attribute, as it is not referenced elsewhere-->
    <EXPOSED_OBJECTS object_ids="view3d.shapes.opacity"/>
</SKIN>

OpenGL script file (openGLShapes.cxx):

// function used to render simple OpenGL shapes
void glRenderShapes(float opacity)
{
    // render cube
    glBegin(GL_QUADS);
    // Top face (y = 1.0f)
    glColor4f(0.0f, 1.0f, 0.0f,opacity);     // Green
    glVertex3f( 1.0f, 1.0f, -1.0f);
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(-1.0f, 1.0f,  1.0f);
    glVertex3f( 1.0f, 1.0f,  1.0f);

    // Bottom face (y = -1.0f)
    glColor4f(1.0f, 0.5f, 0.0f,opacity);     // Orange
    glVertex3f( 1.0f, -1.0f,  1.0f);
    glVertex3f(-1.0f, -1.0f,  1.0f);
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f( 1.0f, -1.0f, -1.0f);

    // Front face  (z = 1.0f)
    glColor4f(1.0f, 0.0f, 0.0f,opacity);     // Red
    glVertex3f( 1.0f,  1.0f, 1.0f);
    glVertex3f(-1.0f,  1.0f, 1.0f);
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glVertex3f( 1.0f, -1.0f, 1.0f);

    // Back face (z = -1.0f)
    glColor4f(1.0f, 1.0f, 0.0f,opacity);     // Yellow
    glVertex3f( 1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f,  1.0f, -1.0f);
    glVertex3f( 1.0f,  1.0f, -1.0f);

    // Left face (x = -1.0f)
    glColor4f(0.0f, 0.0f, 1.0f,opacity);     // Blue
    glVertex3f(-1.0f,  1.0f,  1.0f);
    glVertex3f(-1.0f,  1.0f, -1.0f);
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f, -1.0f,  1.0f);

    // Right face (x = 1.0f)
    glColor4f(1.0f, 0.0f, 1.0f,opacity);     // Magenta
    glVertex3f(1.0f,  1.0f, -1.0f);
    glVertex3f(1.0f,  1.0f,  1.0f);
    glVertex3f(1.0f, -1.0f,  1.0f);
    glVertex3f(1.0f, -1.0f, -1.0f);
    glEnd();

    // Render a pyramid
    glTranslatef(-1.5f, 0.0f, -6.0f);  // Move

    glBegin(GL_TRIANGLES);
    // Front
    glColor4f(1.0f, 0.0f, 0.0f,opacity);     // Red
    glVertex3f( 0.0f, 1.0f, 0.0f);
    glColor4f(0.0f, 1.0f, 0.0f,opacity);     // Green
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glColor4f(0.0f, 0.0f, 1.0f,opacity);     // Blue
    glVertex3f(1.0f, -1.0f, 1.0f);

    // Right
    glColor4f(1.0f, 0.0f, 0.0f,opacity);     // Red
    glVertex3f(0.0f, 1.0f, 0.0f);
    glColor4f(0.0f, 0.0f, 1.0f,opacity);     // Blue
    glVertex3f(1.0f, -1.0f, 1.0f);
    glColor4f(0.0f, 1.0f, 0.0f,opacity);     // Green
    glVertex3f(1.0f, -1.0f, -1.0f);

    // Back
    glColor4f(1.0f, 0.0f, 0.0f,opacity);     // Red
    glVertex3f(0.0f, 1.0f, 0.0f);
    glColor4f(0.0f, 1.0f, 0.0f,opacity);     // Green
    glVertex3f(1.0f, -1.0f, -1.0f);
    glColor4f(0.0f, 0.0f, 1.0f,opacity);     // Blue
    glVertex3f(-1.0f, -1.0f, -1.0f);

    // Left
    glColor4f(1.0f,0.0f,0.0f,opacity);       // Red
    glVertex3f( 0.0f, 1.0f, 0.0f);
    glColor4f(0.0f,0.0f,1.0f,opacity);       // Blue
    glVertex3f(-1.0f,-1.0f,-1.0f);
    glColor4f(0.0f,1.0f,0.0f,opacity);       // Green
    glVertex3f(-1.0f,-1.0f, 1.0f);
    glEnd();
}