gnu.app.redbook.AntiAlias Maven / Gradle / Ivy
Show all versions of escher Show documentation
package gnu.app.redbook;
import gnu.x11.extension.glx.GL;
import gnu.x11.extension.glx.GLU;
/**
* Utility for anti-aliasing. Modified from accpersp.h.
*/
class AntiAlias {
/**
* {@link GLU.frustum} with anti-aliasing.
*
* Other arguments are identical to {@link GLU.frustum}. Set
* both `pixdx' and `pixdy' equal to 0.0 for no anti-alias jitter. Set
* both `eyex' and `eyey' equal to 0.0 for no depth of field effects.
*
* @param pixdx x of anti-alias jitter in pixels
* @param pixdy y of anti-alias jitter in pixels
* @param eyedx x of depth-of field jitter in pixels
* @param eyedy y of depth-of field jitter in pixels
* @param focus distance from eye to plane in focus, must be greater
* than, but not equal to 0.0
*/
static void frustum (GL gl, int window_width, int window_height,
double left, double right, double bottom, double top,
double near, double far, double pixdx, double pixdy,
double eyedx, double eyedy, double focus) {
double xwsize = right - left;
double ywsize = top - bottom;
double dx = pixdx*xwsize/window_width + eyedx*near/focus;
double dy = pixdy*ywsize/window_height + eyedy*near/focus;
gl.matrix_mode (GL.PROJECTION);
gl.load_identity ();
gl.frustum (left-dx, right-dx, bottom-dy, top-dy, near, far);
gl.matrix_mode (GL.MODELVIEW);
gl.load_identity ();
gl.translatef ((float) -eyedx, (float) -eyedy, 0.0f);
}
/**
* {@link GLU.perspective} with anti-aliasing.
*
*
Other arguments are identical to {@link GLU.perspective}. Set
* both `pixdx' and `pixdy' equal to 0.0 for no anti-alias jitter. Set
* both `eyex' and `eyey' equal to 0.0 for no depth of field effects.
*
* @param pixdx x of anti-alias jitter in pixels
* @param pixdy y of anti-alias jitter in pixels
* @param eyedx x of depth-of field jitter in pixels
* @param eyedy y of depth-of field jitter in pixels
* @param focus distance from eye to plane in focus, must be greater
* than, but not equal to 0.0
*/
static void perspective (GL gl, int window_width, int window_height,
double fovy, double aspect, double near, double far,
double pixdx, double pixdy, double eyedx, double eyedy, double focus) {
// identical to code of `GLU.perspective'
double ymax = near * Math.tan (Math.toRadians (fovy/2));
double ymin = -ymax;
double xmin = ymin * aspect;
double xmax = ymax * aspect;
frustum (gl, window_width, window_height,
xmin, xmax, ymin, ymax, near, far,
pixdx, pixdy, eyedx, eyedy, focus);
}
}