001    package net.minecraft.src;
002    
003    import cpw.mods.fml.common.Side;
004    import cpw.mods.fml.common.asm.SideOnly;
005    import java.nio.FloatBuffer;
006    import org.lwjgl.opengl.GL11;
007    
008    @SideOnly(Side.CLIENT)
009    public class ClippingHelperImpl extends ClippingHelper
010    {
011        private static ClippingHelperImpl instance = new ClippingHelperImpl();
012        private FloatBuffer projectionMatrixBuffer = GLAllocation.createDirectFloatBuffer(16);
013        private FloatBuffer modelviewMatrixBuffer = GLAllocation.createDirectFloatBuffer(16);
014        private FloatBuffer field_78564_h = GLAllocation.createDirectFloatBuffer(16);
015    
016        /**
017         * Initialises the ClippingHelper object then returns an instance of it.
018         */
019        public static ClippingHelper getInstance()
020        {
021            instance.init();
022            return instance;
023        }
024    
025        /**
026         * Normalize the frustum.
027         */
028        private void normalize(float[][] par1ArrayOfFloat, int par2)
029        {
030            float var3 = MathHelper.sqrt_float(par1ArrayOfFloat[par2][0] * par1ArrayOfFloat[par2][0] + par1ArrayOfFloat[par2][1] * par1ArrayOfFloat[par2][1] + par1ArrayOfFloat[par2][2] * par1ArrayOfFloat[par2][2]);
031            par1ArrayOfFloat[par2][0] /= var3;
032            par1ArrayOfFloat[par2][1] /= var3;
033            par1ArrayOfFloat[par2][2] /= var3;
034            par1ArrayOfFloat[par2][3] /= var3;
035        }
036    
037        private void init()
038        {
039            this.projectionMatrixBuffer.clear();
040            this.modelviewMatrixBuffer.clear();
041            this.field_78564_h.clear();
042            GL11.glGetFloat(GL11.GL_PROJECTION_MATRIX, this.projectionMatrixBuffer);
043            GL11.glGetFloat(GL11.GL_MODELVIEW_MATRIX, this.modelviewMatrixBuffer);
044            this.projectionMatrixBuffer.flip().limit(16);
045            this.projectionMatrixBuffer.get(this.projectionMatrix);
046            this.modelviewMatrixBuffer.flip().limit(16);
047            this.modelviewMatrixBuffer.get(this.modelviewMatrix);
048            this.clippingMatrix[0] = this.modelviewMatrix[0] * this.projectionMatrix[0] + this.modelviewMatrix[1] * this.projectionMatrix[4] + this.modelviewMatrix[2] * this.projectionMatrix[8] + this.modelviewMatrix[3] * this.projectionMatrix[12];
049            this.clippingMatrix[1] = this.modelviewMatrix[0] * this.projectionMatrix[1] + this.modelviewMatrix[1] * this.projectionMatrix[5] + this.modelviewMatrix[2] * this.projectionMatrix[9] + this.modelviewMatrix[3] * this.projectionMatrix[13];
050            this.clippingMatrix[2] = this.modelviewMatrix[0] * this.projectionMatrix[2] + this.modelviewMatrix[1] * this.projectionMatrix[6] + this.modelviewMatrix[2] * this.projectionMatrix[10] + this.modelviewMatrix[3] * this.projectionMatrix[14];
051            this.clippingMatrix[3] = this.modelviewMatrix[0] * this.projectionMatrix[3] + this.modelviewMatrix[1] * this.projectionMatrix[7] + this.modelviewMatrix[2] * this.projectionMatrix[11] + this.modelviewMatrix[3] * this.projectionMatrix[15];
052            this.clippingMatrix[4] = this.modelviewMatrix[4] * this.projectionMatrix[0] + this.modelviewMatrix[5] * this.projectionMatrix[4] + this.modelviewMatrix[6] * this.projectionMatrix[8] + this.modelviewMatrix[7] * this.projectionMatrix[12];
053            this.clippingMatrix[5] = this.modelviewMatrix[4] * this.projectionMatrix[1] + this.modelviewMatrix[5] * this.projectionMatrix[5] + this.modelviewMatrix[6] * this.projectionMatrix[9] + this.modelviewMatrix[7] * this.projectionMatrix[13];
054            this.clippingMatrix[6] = this.modelviewMatrix[4] * this.projectionMatrix[2] + this.modelviewMatrix[5] * this.projectionMatrix[6] + this.modelviewMatrix[6] * this.projectionMatrix[10] + this.modelviewMatrix[7] * this.projectionMatrix[14];
055            this.clippingMatrix[7] = this.modelviewMatrix[4] * this.projectionMatrix[3] + this.modelviewMatrix[5] * this.projectionMatrix[7] + this.modelviewMatrix[6] * this.projectionMatrix[11] + this.modelviewMatrix[7] * this.projectionMatrix[15];
056            this.clippingMatrix[8] = this.modelviewMatrix[8] * this.projectionMatrix[0] + this.modelviewMatrix[9] * this.projectionMatrix[4] + this.modelviewMatrix[10] * this.projectionMatrix[8] + this.modelviewMatrix[11] * this.projectionMatrix[12];
057            this.clippingMatrix[9] = this.modelviewMatrix[8] * this.projectionMatrix[1] + this.modelviewMatrix[9] * this.projectionMatrix[5] + this.modelviewMatrix[10] * this.projectionMatrix[9] + this.modelviewMatrix[11] * this.projectionMatrix[13];
058            this.clippingMatrix[10] = this.modelviewMatrix[8] * this.projectionMatrix[2] + this.modelviewMatrix[9] * this.projectionMatrix[6] + this.modelviewMatrix[10] * this.projectionMatrix[10] + this.modelviewMatrix[11] * this.projectionMatrix[14];
059            this.clippingMatrix[11] = this.modelviewMatrix[8] * this.projectionMatrix[3] + this.modelviewMatrix[9] * this.projectionMatrix[7] + this.modelviewMatrix[10] * this.projectionMatrix[11] + this.modelviewMatrix[11] * this.projectionMatrix[15];
060            this.clippingMatrix[12] = this.modelviewMatrix[12] * this.projectionMatrix[0] + this.modelviewMatrix[13] * this.projectionMatrix[4] + this.modelviewMatrix[14] * this.projectionMatrix[8] + this.modelviewMatrix[15] * this.projectionMatrix[12];
061            this.clippingMatrix[13] = this.modelviewMatrix[12] * this.projectionMatrix[1] + this.modelviewMatrix[13] * this.projectionMatrix[5] + this.modelviewMatrix[14] * this.projectionMatrix[9] + this.modelviewMatrix[15] * this.projectionMatrix[13];
062            this.clippingMatrix[14] = this.modelviewMatrix[12] * this.projectionMatrix[2] + this.modelviewMatrix[13] * this.projectionMatrix[6] + this.modelviewMatrix[14] * this.projectionMatrix[10] + this.modelviewMatrix[15] * this.projectionMatrix[14];
063            this.clippingMatrix[15] = this.modelviewMatrix[12] * this.projectionMatrix[3] + this.modelviewMatrix[13] * this.projectionMatrix[7] + this.modelviewMatrix[14] * this.projectionMatrix[11] + this.modelviewMatrix[15] * this.projectionMatrix[15];
064            this.frustum[0][0] = this.clippingMatrix[3] - this.clippingMatrix[0];
065            this.frustum[0][1] = this.clippingMatrix[7] - this.clippingMatrix[4];
066            this.frustum[0][2] = this.clippingMatrix[11] - this.clippingMatrix[8];
067            this.frustum[0][3] = this.clippingMatrix[15] - this.clippingMatrix[12];
068            this.normalize(this.frustum, 0);
069            this.frustum[1][0] = this.clippingMatrix[3] + this.clippingMatrix[0];
070            this.frustum[1][1] = this.clippingMatrix[7] + this.clippingMatrix[4];
071            this.frustum[1][2] = this.clippingMatrix[11] + this.clippingMatrix[8];
072            this.frustum[1][3] = this.clippingMatrix[15] + this.clippingMatrix[12];
073            this.normalize(this.frustum, 1);
074            this.frustum[2][0] = this.clippingMatrix[3] + this.clippingMatrix[1];
075            this.frustum[2][1] = this.clippingMatrix[7] + this.clippingMatrix[5];
076            this.frustum[2][2] = this.clippingMatrix[11] + this.clippingMatrix[9];
077            this.frustum[2][3] = this.clippingMatrix[15] + this.clippingMatrix[13];
078            this.normalize(this.frustum, 2);
079            this.frustum[3][0] = this.clippingMatrix[3] - this.clippingMatrix[1];
080            this.frustum[3][1] = this.clippingMatrix[7] - this.clippingMatrix[5];
081            this.frustum[3][2] = this.clippingMatrix[11] - this.clippingMatrix[9];
082            this.frustum[3][3] = this.clippingMatrix[15] - this.clippingMatrix[13];
083            this.normalize(this.frustum, 3);
084            this.frustum[4][0] = this.clippingMatrix[3] - this.clippingMatrix[2];
085            this.frustum[4][1] = this.clippingMatrix[7] - this.clippingMatrix[6];
086            this.frustum[4][2] = this.clippingMatrix[11] - this.clippingMatrix[10];
087            this.frustum[4][3] = this.clippingMatrix[15] - this.clippingMatrix[14];
088            this.normalize(this.frustum, 4);
089            this.frustum[5][0] = this.clippingMatrix[3] + this.clippingMatrix[2];
090            this.frustum[5][1] = this.clippingMatrix[7] + this.clippingMatrix[6];
091            this.frustum[5][2] = this.clippingMatrix[11] + this.clippingMatrix[10];
092            this.frustum[5][3] = this.clippingMatrix[15] + this.clippingMatrix[14];
093            this.normalize(this.frustum, 5);
094        }
095    }