/**
* Sets the GL lighting state to a white light originating from the eye position and pointed in the specified
* direction, in model coordinates. The light direction is always relative to the current eye point and viewer
* direction. If the direction is null, this the light direction defaults to (0, 0, -1), which points directly along
* the forward vector form the eye point
*
* @param gl the GL context.
* @param light the GL light name to set.
* @param direction the light direction in model coordinates, may be null.
*
* @throws ArgumentException if the GL is null.
*/
public static void applyLightingDirectionalFromViewer(GL2 gl, int light, Vec4 direction)
{
if (gl == null)
{
String message = Logging.getMessage("nullValue.GLIsNull");
Logging.logger().severe(message);
throw new ArgumentException(message);
}
if (direction == null)
{
direction = DEFAULT_LIGHT_DIRECTION;
}
float[] ambient = { 1f, 1f, 1f, 0f };
float[] diffuse = { 1f, 1f, 1f, 0f };
float[] specular = { 1f, 1f, 1f, 0f };
float[] position = { (float)direction.x, (float)direction.y, (float)direction.z, 0.0f };
gl.glLightfv(light, GL2.GL_AMBIENT, ambient, 0);
gl.glLightfv(light, GL2.GL_DIFFUSE, diffuse, 0);
gl.glLightfv(light, GL2.GL_SPECULAR, specular, 0);
OGLStackHandler ogsh = new OGLStackHandler();
ogsh.pushModelviewIdentity(gl);
try
{
gl.glLightfv(light, GL2.GL_POSITION, position, 0);
}
finally
{
ogsh.pop(gl);
}
}
protected static void applyStandardLightMaterial(GL2 gl, int light, Material material)
{
// The alpha value at a vertex is taken only from the diffuse material's alpha channel, without any
// lighting computations applied. Therefore we specify alpha=0 for all lighting ambient, specular and
// emission values. This will have no effect on material alpha.
float[] ambient = new float[4];
float[] diffuse = new float[4];
float[] specular = new float[4];
material.getDiffuse().getRGBColorComponents(diffuse);
material.getSpecular().getRGBColorComponents(specular);
ambient[3] = diffuse[3] = specular[3] = 0.0f;
gl.glLightfv(light, GL2.GL_AMBIENT, ambient, 0);
gl.glLightfv(light, GL2.GL_DIFFUSE, diffuse, 0);
gl.glLightfv(light, GL2.GL_SPECULAR, specular, 0);
}
protected void applyStandardLightDirection(GL2 gl, int light, Vec4 direction)
{
// Setup the light as a directional light coming from the viewpoint. This requires two state changes
// (a) Set the light position as direction x, y, z, and set the w-component to 0, which tells OpenGL this is
// a directional light.
// (b) Invoke the light position call with the identity matrix on the modelview stack. Since the position
// is transformed by the
Vec4 vec = direction.normalize3();
float[] parameters = new float[4];
parameters[0] = (float)vec.x;
parameters[1] = (float)vec.y;
parameters[2] = (float)vec.z;
parameters[3] = 0.0f;
gl.glMatrixMode(GL2.GL_MODELVIEW);
gl.glPushMatrix();
gl.glLoadIdentity();
gl.glLightfv(light, GL2.GL_POSITION, parameters, 0);
gl.glPopMatrix();
}
