247 lines
5.1 KiB
Java
247 lines
5.1 KiB
Java
/*
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* Copyright (c) 2002-2004 LWJGL Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* * Neither the name of 'LWJGL' nor the names of
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* its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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package org.lwjgl.opengl.glu;
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import java.nio.IntBuffer;
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import org.lwjgl.BufferUtils;
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import org.lwjgl.opengl.GL11;
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import org.lwjgl.opengl.GL12;
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/**
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* Util.java
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* <p/>
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* <p/>
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* Created 7-jan-2004
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*
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* @author Erik Duijs
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*/
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public class Util {
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/**
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* temp IntBuffer of one for getting an int from some GL functions
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*/
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private static IntBuffer scratch = BufferUtils.createIntBuffer(16);
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/**
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* Return ceiling of integer division
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*
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* @param a
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* @param b
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*
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* @return int
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*/
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protected static int ceil(int a, int b) {
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return (a % b == 0 ? a / b : a / b + 1);
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}
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/**
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* Normalize vector
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*
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* @param v
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*
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* @return float[]
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*/
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protected static float[] normalize(float[] v) {
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float r;
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r = (float)Math.sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
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if ( r == 0.0 )
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return v;
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r = 1.0f / r;
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v[0] *= r;
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v[1] *= r;
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v[2] *= r;
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return v;
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}
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/**
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* Calculate cross-product
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*
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* @param v1
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* @param v2
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* @param result
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*/
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protected static void cross(float[] v1, float[] v2, float[] result) {
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result[0] = v1[1] * v2[2] - v1[2] * v2[1];
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result[1] = v1[2] * v2[0] - v1[0] * v2[2];
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result[2] = v1[0] * v2[1] - v1[1] * v2[0];
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}
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/**
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* Method compPerPix.
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*
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* @param format
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*
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* @return int
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*/
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protected static int compPerPix(int format) {
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/* Determine number of components per pixel */
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switch ( format ) {
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case GL11.GL_COLOR_INDEX:
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case GL11.GL_STENCIL_INDEX:
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case GL11.GL_DEPTH_COMPONENT:
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case GL11.GL_RED:
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case GL11.GL_GREEN:
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case GL11.GL_BLUE:
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case GL11.GL_ALPHA:
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case GL11.GL_LUMINANCE:
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return 1;
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case GL11.GL_LUMINANCE_ALPHA:
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return 2;
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case GL11.GL_RGB:
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case GL12.GL_BGR:
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return 3;
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case GL11.GL_RGBA:
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case GL12.GL_BGRA:
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return 4;
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default :
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return -1;
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}
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}
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/**
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* Method nearestPower.
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* <p/>
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* Compute the nearest power of 2 number. This algorithm is a little strange, but it works quite well.
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*
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* @param value
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*
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* @return int
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*/
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protected static int nearestPower(int value) {
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int i;
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i = 1;
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/* Error! */
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if ( value == 0 )
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return -1;
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for ( ; ; ) {
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if ( value == 1 ) {
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return i;
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} else if ( value == 3 ) {
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return i << 2;
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}
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value >>= 1;
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i <<= 1;
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}
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}
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/**
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* Method bytesPerPixel.
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*
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* @param format
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* @param type
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*
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* @return int
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*/
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protected static int bytesPerPixel(int format, int type) {
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int n, m;
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switch ( format ) {
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case GL11.GL_COLOR_INDEX:
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case GL11.GL_STENCIL_INDEX:
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case GL11.GL_DEPTH_COMPONENT:
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case GL11.GL_RED:
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case GL11.GL_GREEN:
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case GL11.GL_BLUE:
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case GL11.GL_ALPHA:
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case GL11.GL_LUMINANCE:
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n = 1;
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break;
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case GL11.GL_LUMINANCE_ALPHA:
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n = 2;
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break;
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case GL11.GL_RGB:
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case GL12.GL_BGR:
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n = 3;
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break;
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case GL11.GL_RGBA:
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case GL12.GL_BGRA:
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n = 4;
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break;
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default :
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n = 0;
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}
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switch ( type ) {
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case GL11.GL_UNSIGNED_BYTE:
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m = 1;
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break;
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case GL11.GL_BYTE:
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m = 1;
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break;
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case GL11.GL_BITMAP:
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m = 1;
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break;
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case GL11.GL_UNSIGNED_SHORT:
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m = 2;
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break;
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case GL11.GL_SHORT:
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m = 2;
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break;
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case GL11.GL_UNSIGNED_INT:
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m = 4;
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break;
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case GL11.GL_INT:
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m = 4;
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break;
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case GL11.GL_FLOAT:
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m = 4;
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break;
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default :
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m = 0;
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}
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return n * m;
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}
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/**
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* Convenience method for returning an int, rather than getting it out of a buffer yourself.
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*
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* @param what
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*
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* @return int
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*/
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protected static int glGetIntegerv(int what) {
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scratch.rewind();
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GL11.glGetInteger(what, scratch);
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return scratch.get();
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}
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}
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