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///////////////////////////////////////////////////////////////////////////////////////////////////
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// Copyright 2020 Leszek Koltunski //
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// //
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// This file is part of Distorted. //
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// //
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// Distorted is free software: you can redistribute it and/or modify //
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// it under the terms of the GNU General Public License as published by //
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// the Free Software Foundation, either version 2 of the License, or //
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// (at your option) any later version. //
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// //
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// Distorted is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY; without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
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// GNU General Public License for more details. //
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// //
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// You should have received a copy of the GNU General Public License //
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// along with Distorted. If not, see <http://www.gnu.org/licenses/>. //
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///////////////////////////////////////////////////////////////////////////////////////////////////
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package org.distorted.library.mesh;
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///////////////////////////////////////////////////////////////////////////////////////////////////
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/**
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* Create a polygon of any shape and varying elevations from the edges towards the center.
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* <p>
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* Specify a list of vertices. Any two adjacent vertices + the center (0,0,0) form a triangle. The
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* polygon is going to be split into such triangles, and each triange is split into adjustable number
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* of 'bands' form the outer edge towards the center. Edges of each band can can at any elevation.
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*/
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public class MeshPolygon extends MeshBase
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{
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private float[] mPolygonVertices;
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private int mNumPolygonVertices;
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private float[] mPolygonBands;
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private int mNumPolygonBands;
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private int remainingVert;
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private int numVertices;
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private int extraIndex, extraVertices;
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private float[] mBandQuot;
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// polygonVertices>=3 , polygonBands>=2
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private void computeNumberOfVertices()
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{
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numVertices = (mNumPolygonVertices*mNumPolygonBands+2)*(mNumPolygonBands-1) - 1;
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numVertices+= 2*mNumPolygonVertices*(2*extraIndex*extraVertices);
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remainingVert = numVertices;
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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private void computeCache()
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{
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mBandQuot = new float[mNumPolygonBands];
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int next, prev;
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for(int band=0; band<mNumPolygonBands; band++)
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{
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next = (band==mNumPolygonBands-1 ? band : band+1);
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prev = (band== 0 ? band : band-1);
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mBandQuot[band] = (mPolygonBands[2*prev+1]-mPolygonBands[2*next+1]) / (mPolygonBands[2*next]-mPolygonBands[2*prev]);
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}
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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private float getQuot(int index, int band, boolean isExtra)
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{
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int num = mNumPolygonBands-1-band;
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if( num>0 )
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{
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if( isExtra )
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{
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int extra = extraIndex-band+extraVertices;
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if( index < extra )
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{
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float quot = ((float)extraIndex-band)/(extra*num);
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return index*quot;
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}
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else if( index > num+2*extraVertices-extra )
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{
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float quot = ((float)extraIndex-band)/(extra*num);
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return (1.0f-((float)extraIndex-band)/num) + (index-num-2*extraVertices+extra)*quot;
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}
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else
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{
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return ((float)(index-extraVertices))/num;
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}
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}
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return (float)index/num;
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}
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return 1.0f;
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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private int addVertex(int vertex, int polyBand, int polyVertex, int polyEndVer, float quot, float[] attribs1, float[] attribs2)
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{
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remainingVert--;
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float vx,vy,vz;
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float Xfirst= mPolygonVertices[2*polyVertex ];
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float Yfirst= mPolygonVertices[2*polyVertex+1];
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float Xlast = mPolygonVertices[2*polyEndVer ];
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float Ylast = mPolygonVertices[2*polyEndVer+1];
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float xEdge = Xfirst + quot*(Xlast-Xfirst);
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float yEdge = Yfirst + quot*(Ylast-Yfirst);
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float x = mPolygonBands[2*polyBand]*xEdge;
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float y = mPolygonBands[2*polyBand]*yEdge;
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if( quot==0.0f || quot==1.0f )
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{
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vx = mBandQuot[polyBand]*xEdge;
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vy = mBandQuot[polyBand]*yEdge;
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vz = xEdge*xEdge + yEdge*yEdge;
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}
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else
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{
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vx = mBandQuot[polyBand]*(Ylast-Yfirst);
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vy = mBandQuot[polyBand]*(Xfirst-Xlast);
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float tmp = Xfirst*Ylast - Xlast*Yfirst;
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vz = (tmp<0 ? -tmp:tmp);
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}
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float len = (float)Math.sqrt(vx*vx + vy*vy + vz*vz);
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attribs1[VERT1_ATTRIBS*vertex + POS_ATTRIB ] = x;
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attribs1[VERT1_ATTRIBS*vertex + POS_ATTRIB+1] = y;
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attribs1[VERT1_ATTRIBS*vertex + POS_ATTRIB+2] = mPolygonBands[2*polyBand+1];
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attribs1[VERT1_ATTRIBS*vertex + NOR_ATTRIB ] = vx/len;
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attribs1[VERT1_ATTRIBS*vertex + NOR_ATTRIB+1] = vy/len;
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attribs1[VERT1_ATTRIBS*vertex + NOR_ATTRIB+2] = vz/len;
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attribs2[VERT2_ATTRIBS*vertex + TEX_ATTRIB ] = x+0.5f;
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attribs2[VERT2_ATTRIBS*vertex + TEX_ATTRIB+1] = y+0.5f;
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return vertex+1;
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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private int createBandStrip(int vertex, int polyBand, int polyVertex, float[] attribs1, float[] attribs2)
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{
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if( polyVertex==0 )
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{
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vertex = addVertex(vertex,polyBand,0,1,0,attribs1,attribs2);
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if( polyBand>0 )
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{
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vertex = addVertex(vertex,polyBand,0,1,0,attribs1,attribs2);
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}
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}
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int numPairs = mNumPolygonBands-1-polyBand;
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boolean isExtra = polyBand<extraIndex;
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if( isExtra )
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{
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numPairs += 2*extraVertices;
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}
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int polyEndVer = polyVertex==mNumPolygonVertices-1 ? 0 : polyVertex+1;
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float quot1, quot2;
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for(int index=0; index<numPairs; index++)
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{
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quot1 = getQuot(index ,polyBand+1, isExtra);
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quot2 = getQuot(index+1,polyBand , isExtra);
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vertex = addVertex(vertex,polyBand+1,polyVertex,polyEndVer,quot1,attribs1,attribs2);
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vertex = addVertex(vertex,polyBand ,polyVertex,polyEndVer,quot2,attribs1,attribs2);
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}
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return vertex;
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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private void buildGrid(float[] attribs1, float[] attribs2)
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{
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int vertex=0;
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for(int polyBand=0; polyBand<mNumPolygonBands-1; polyBand++)
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for(int polyVertex=0; polyVertex<mNumPolygonVertices; polyVertex++)
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{
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vertex = createBandStrip(vertex,polyBand,polyVertex,attribs1,attribs2);
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}
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// PUBLIC API
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///////////////////////////////////////////////////////////////////////////////////////////////////
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/**
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* Create a polygon of any shape and varying elevations from the edges towards the center.
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* Optionally make it more dense at the vertices.
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*
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* @param verticesXY 2N floats - packed description of polygon vertices. N pairs (x,y).
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* Vertices HAVE TO be specified in a COUNTERCLOCKWISE order (starting from any).
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* @param bands 2K floats; K pairs of two floats each describing a single band.
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* From (1.0,Z[0]) (outer edge, its Z elevation) to (0.0,Z[K]) (the center,
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* its elevation). The polygon is split into such concentric bands.
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* Must be band[2*i] > band[2*(i+1)] !
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* @param exIndex This and the next parameter describe how to make the mesh denser at the
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* polyVertices. If e.g. exIndex=3 and exVertices=2, then 3 triangles of the
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* outermost band (and 2 traingles of the next band, and 1 triange of the third
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* band) get denser - the 3 triangles become 3+2 = 5.
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* @param exVertices See above.
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*/
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public MeshPolygon(float[] verticesXY, float[] bands, int exIndex, int exVertices)
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{
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super();
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mPolygonVertices = verticesXY;
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mPolygonBands = bands;
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mNumPolygonVertices= mPolygonVertices.length /2;
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mNumPolygonBands = mPolygonBands.length /2;
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extraIndex = exIndex;
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extraVertices = exVertices;
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computeNumberOfVertices();
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computeCache();
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float[] attribs1= new float[VERT1_ATTRIBS*numVertices];
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float[] attribs2= new float[VERT2_ATTRIBS*numVertices];
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buildGrid(attribs1,attribs2);
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if( remainingVert!=0 )
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android.util.Log.d("MeshPolygon", "remainingVert " +remainingVert );
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setAttribs(attribs1,attribs2);
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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/**
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* Create a polygon of any shape and varying elevations from the edges towards the center.
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* Equivalent of the previous with exIndex=0 or exVertices=0.
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*/
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public MeshPolygon(float[] verticesXY, float[] bands)
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{
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this(verticesXY,bands,0,0);
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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/**
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* Copy constructor.
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*/
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public MeshPolygon(MeshPolygon mesh, boolean deep)
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{
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super(mesh,deep);
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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/**
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* Copy the Mesh.
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*
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* @param deep If to be a deep or shallow copy of mVertAttribs1, i.e. the array holding vertices,
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* normals and inflates (the rest, in particular the mVertAttribs2 containing texture
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* coordinates and effect associations, is always deep copied)
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*/
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public MeshPolygon copy(boolean deep)
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{
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return new MeshPolygon(this,deep);
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}
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}
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