package org.lwjgl.opengl.glu;

import org.lwjgl.opengl.GL;

/**
 * Cylinder.java
 * 
 * 
 * Created 23-dec-2003
 * @author Erik Duijs
 */
public class Cylinder extends Quadric implements GLUConstants {

	/**
	 * Constructor for Cylinder.
	 */
	public Cylinder() {
		super();
	}

	/**
	 * draws a cylinder oriented along the z axis. The base of the
	 * cylinder is placed at z = 0, and the top at z=height. Like a sphere, a
	 * cylinder is subdivided around the z axis into slices, and along the z axis
	 * into stacks.
	 *
	 * Note that if topRadius is set to zero, then this routine will generate a
	 * cone.
	 *
	 * If the orientation is set to GLU.OUTSIDE (with glu.quadricOrientation), then
	 * any generated normals point away from the z axis. Otherwise, they point
	 * toward the z axis.
	 *
	 * If texturing is turned on (with glu.quadricTexture), then texture
	 * coordinates are generated so that t ranges linearly from 0.0 at z = 0 to
	 * 1.0 at z = height, and s ranges from 0.0 at the +y axis, to 0.25 at the +x
	 * axis, to 0.5 at the -y axis, to 0.75 at the -x axis, and back to 1.0 at the
	 * +y axis.
	 *
	 * @param baseRadius  Specifies the radius of the cylinder at z = 0.
	 * @param topRadius   Specifies the radius of the cylinder at z = height.
	 * @param height      Specifies the height of the cylinder.
	 * @param slices      Specifies the number of subdivisions around the z axis.
	 * @param stacks      Specifies the number of subdivisions along the z axis.
	 */
	public void draw(float baseRadius, float topRadius, float height, int slices, int stacks) {

		float da, r, dr, dz;
		float x, y, z, nz, nsign;
		int i, j;

		if (super.orientation == GLU_INSIDE) {
			nsign = -1.0f;
		} else {
			nsign = 1.0f;
		}

		da = 2.0f * PI / slices;
		dr = (topRadius - baseRadius) / stacks;
		dz = height / stacks;
		nz = (baseRadius - topRadius) / height;
		// Z component of normal vectors

		if (super.drawStyle == GLU_POINT) {
			GL.glBegin(GL.GL_POINTS);
			for (i = 0; i < slices; i++) {
				x = cos((i * da));
				y = sin((i * da));
				normal3f(x * nsign, y * nsign, nz * nsign);

				z = 0.0f;
				r = baseRadius;
				for (j = 0; j <= stacks; j++) {
					GL.glVertex3f((x * r), (y * r), z);
					z += dz;
					r += dr;
				}
			}
			GL.glEnd();
		} else if (super.drawStyle == GLU_LINE || super.drawStyle == GLU_SILHOUETTE) {
			// Draw rings
			if (super.drawStyle == GLU_LINE) {
				z = 0.0f;
				r = baseRadius;
				for (j = 0; j <= stacks; j++) {
					GL.glBegin(GL.GL_LINE_LOOP);
					for (i = 0; i < slices; i++) {
						x = cos((i * da));
						y = sin((i * da));
						normal3f(x * nsign, y * nsign, nz * nsign);
						GL.glVertex3f((x * r), (y * r), z);
					}
					GL.glEnd();
					z += dz;
					r += dr;
				}
			} else {
				// draw one ring at each end
				if (baseRadius != 0.0) {
					GL.glBegin(GL.GL_LINE_LOOP);
					for (i = 0; i < slices; i++) {
						x = cos((i * da));
						y = sin((i * da));
						normal3f(x * nsign, y * nsign, nz * nsign);
						GL.glVertex3f((x * baseRadius), (y * baseRadius), 0.0f);
					}
					GL.glEnd();
					GL.glBegin(GL.GL_LINE_LOOP);
					for (i = 0; i < slices; i++) {
						x = cos((i * da));
						y = sin((i * da));
						normal3f(x * nsign, y * nsign, nz * nsign);
						GL.glVertex3f((x * topRadius), (y * topRadius), height);
					}
					GL.glEnd();
				}
			}
			// draw length lines
			GL.glBegin(GL.GL_LINES);
			for (i = 0; i < slices; i++) {
				x = cos((i * da));
				y = sin((i * da));
				normal3f(x * nsign, y * nsign, nz * nsign);
				GL.glVertex3f((x * baseRadius), (y * baseRadius), 0.0f);
				GL.glVertex3f((x * topRadius), (y * topRadius), (height));
			}
			GL.glEnd();
		} else if (super.drawStyle == GLU_FILL) {
			float ds = 1.0f / slices;
			float dt = 1.0f / stacks;
			float t = 0.0f;
			z = 0.0f;
			r = baseRadius;
			for (j = 0; j < stacks; j++) {
				float s = 0.0f;
				GL.glBegin(GL.GL_QUAD_STRIP);
				for (i = 0; i <= slices; i++) {
					if (i == slices) {
						x = sin(0.0f);
						y = cos(0.0f);
					} else {
						x = sin((i * da));
						y = cos((i * da));
					}
					if (nsign == 1.0f) {
						normal3f((x * nsign), (y * nsign), (nz * nsign));
						TXTR_COORD(s, t);
						GL.glVertex3f((x * r), (y * r), z);
						normal3f((x * nsign), (y * nsign), (nz * nsign));
						TXTR_COORD(s, t + dt);
						GL.glVertex3f((x * (r + dr)), (y * (r + dr)), (z + dz));
					} else {
						normal3f(x * nsign, y * nsign, nz * nsign);
						TXTR_COORD(s, t);
						GL.glVertex3f((x * r), (y * r), z);
						normal3f(x * nsign, y * nsign, nz * nsign);
						TXTR_COORD(s, t + dt);
						GL.glVertex3f((x * (r + dr)), (y * (r + dr)), (z + dz));
					}
					s += ds;
				} // for slices
				GL.glEnd();
				r += dr;
				t += dt;
				z += dz;
			} // for stacks
		}
	}
}