155 lines
4.3 KiB
C++
155 lines
4.3 KiB
C++
#include "parametricmesh.h"
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#include "glm/ext.hpp"
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#include "phongmaterial.h"
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#define M_PI 3.14159265358979323846
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#define MAGIC_RATIO 0.37139f
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Sphere::Sphere(Material* mat, int n)
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{
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// icosahedron :
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addGroup(mat);
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Group* group = &(indiceGroups[0]);
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// top cap
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createVertex(0, 1);
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for(int i=0; i<5; i++)
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createVertex(i/5.f, 1-MAGIC_RATIO);
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// bottom cap
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createVertex(0, 0);
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for(int i=0; i<5; i++)
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createVertex((i+0.5f)/5.f, MAGIC_RATIO);
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// Compute faces
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for(int i=0; i<5; i++){
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int top = 1;
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int bottom = 7;
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int offset = (i+1)%5;
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// top cap
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addTriangle(0, top+i, top+offset);
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// bottom cap
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addTriangle(6, bottom+offset, bottom+i);
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// middle ribbon
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addTriangle(top+i, bottom+i, top+offset);
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addTriangle(top+offset, bottom+i, bottom+offset);
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}
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// geodesic subdivisions :
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for(int i=0; i<n; i++)
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subdivide(group);
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}
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int Sphere::getEdge(int a, int b)
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{
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Edge* current = edges+a;
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int vid = -1;
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while(vid == -1)
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{
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if(current->b == b)
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vid = current->vertex;
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else if(current->next == NULL)
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{
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vid = positions.size();
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// creating subdivision vertex
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glm::vec3 pos = glm::normalize(positions[a] + positions[b] / 2.f);
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addPosition(pos);
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addNormal(pos);
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// u/v sphériques, cohérents sur toute la sphère sauf des artefacts au niveau des u==0
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float newU = (pos.x < 0 ? 1.5f : 1.f) + atan(pos.z/pos.x)/(2*M_PI);
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float newV = acos(pos.y)/M_PI;
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addTexCoord(newU - floor(newU), newV);
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// alternative, u/v moyennés :
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//v.texCoord = (v0.texCoord + v1.texCoord)/2.f;
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// inserting the new vertex in the edge collection
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if(current->b == -1)
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{
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current->vertex = vid;
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current->b = b;
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}
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else
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current->next = new Edge(b, vid);
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}
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else
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current = current->next;
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}
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return vid;
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}
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void Sphere::subdivide(Group* group)
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{
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edges = new Edge[positions.size()-1];
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int nb_triangles = group->indices.size()/3;
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for(int j=0; j<nb_triangles; j++)
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{
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int vid[3];
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for(int k=0; k<3; k++)
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{
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int idA = group->indices[j*3 + k];
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int idB = group->indices[j*3 + (k+1)%3];
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int a = idA < idB ? idA : idB;
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int b = idA > idB ? idA : idB;
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vid[k] = getEdge(a, b);
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}
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for(int k=0; k<3; k++)
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addTriangle(group->indices[j*3 + k], vid[k], vid[(k+2)%3]);
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addTriangle(vid[0], vid[1], vid[2]);
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}
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delete[](edges);
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group->indices.erase(group->indices.begin(), group->indices.begin()+nb_triangles*3);
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}
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void Sphere::createVertex(float u, float v)
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{
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glm::vec3 pos(cos(u*2*M_PI)*sin(v*M_PI),
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cos(v*M_PI),
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sin(u*2*M_PI)*sin(v*M_PI));
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addPosition(pos);
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addNormal(pos);
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addTexCoord(u, v);
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}
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GridMesh::GridMesh(Material* mat, int width, int height, bool alternate)
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{
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addGroup(mat);
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for(int i=0; i<=width; ++i)
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{
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for(int j=0; j<=height; ++j)
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{
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float x = (float)i/(float)width;
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float y = (float)j/(float)height;
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addPosition(x-0.5f, 0, y-0.5f);
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addNormal(0, 1, 0);
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addTexCoord(x, y);
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if(i > 0 && j > 0)
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{
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if(alternate && (i+j)%2)
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{
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addTriangle(getVertexId(i, j, height),
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getVertexId(i, j-1, height),
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getVertexId(i-1, j, height));
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addTriangle(getVertexId(i-1, j-1, height),
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getVertexId(i-1, j, height),
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getVertexId(i, j-1, height));
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}
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else
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{
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addTriangle(getVertexId(i, j, height),
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getVertexId(i-1, j-1, height),
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getVertexId(i-1, j, height));
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addTriangle(getVertexId(i, j, height),
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getVertexId(i, j-1, height),
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getVertexId(i-1, j-1, height));
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}
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}
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}
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}
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}
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int GridMesh::getVertexId(int i, int j, int height)
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{
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return i*(height+1) + j;
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}
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