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#include "boundingtriangle.h"
#include "Graphics/global.h"
#include "Graphics/modeltransform.h"
#include <iostream>
#include "glm/gtx/hash.hpp"
// ONLY FOR ENVIRONMENTS
BoundingTriangle::BoundingTriangle(const std::vector<glm::vec3> &obj_data,
const std::shared_ptr<ModelTransform> &mt,
bool isGround) :
obj_mt(mt),
m_isGround(isGround)
{
populateTriangleData(obj_data);
calculateBounds(obj_data);
//m_datasize = obj_data.size();
}
glm::vec3 BoundingTriangle::getRandomSurfacePos(){
int randomIndex = std::floor(Global::graphics.generateRandomNumbers(0, m_triangles.size()-1));
int randomVertex = std::floor(Global::graphics.generateRandomNumbers(0, 3));
Triangle randomTri = m_triangles[randomIndex];
if (glm::dot(glm::vec3(0,1,0), randomTri.normal) > 0.2f){
switch(randomVertex){
case 0:
return randomTri.vertexA;
break;
case 1:
return randomTri.vertexB;
break;
default:
return randomTri.vertexC;
break;
}
} else {
// do again until returning a surface triangle
getRandomSurfacePos();
}
}
void BoundingTriangle::addTriangle(const glm::vec3 &vertexA, const glm::vec3 &vertexB, const glm::vec3 &vertexC){
Triangle tri;
tri.vertexA = vertexA;
tri.vertexB = vertexB;
tri.vertexC = vertexC;
tri.edge1 = vertexB - vertexA; // edge ab
tri.edge2 = vertexC - vertexA; // edge bc
tri.normal = glm::normalize(glm::cross(tri.edge1, tri.edge2));
tri.bounds = calculateTriangleBounds(vertexA, vertexB, vertexC);
// if triangle is a ground triangle
if (m_isGround){
if (glm::dot(glm::vec3(0,1,0), tri.normal) > 0.2f){
//std::cout << "area: " << getArea(vertexA, vertexB, vertexC) << std::endl;
tesselateTriangle(vertexA, vertexB, vertexC);
}
}
m_triangles.push_back(tri);
}
float BoundingTriangle::getArea(const glm::vec3 &A, const glm::vec3 &B, const glm::vec3 &C){
glm::vec3 AB = B-A;
glm::vec3 AC = C-A;
return .5f*glm::length((glm::cross(AB,AC)));
}
glm::vec3 BoundingTriangle::getCentroid(const glm::vec3 &A, const glm::vec3 &B, const glm::vec3 &C){
return .333f*(A + B + C);
}
// tesselation into smaller triangles
void BoundingTriangle::tesselateTriangle(const glm::vec3 &A, const glm::vec3 &B, const glm::vec3 &C){
float min_area = 1.5f;
// add centroid if area is small enough
if (getArea(A,B,C) <= min_area){
m_surface_points.push_back(getCentroid(A, B, C));
return;
}
// otherwise divide triangle in 4 (tesselate)
glm::vec3 ab_mid = .5f*(A+B);
glm::vec3 ac_mid = .5f*(A+C);
glm::vec3 bc_mid = .5f*(B+C);
m_surface_points.push_back(ab_mid);
m_surface_points.push_back(ac_mid);
m_surface_points.push_back(bc_mid);
tesselateTriangle(ab_mid, ac_mid, A);
tesselateTriangle(bc_mid, ab_mid, B);
tesselateTriangle(bc_mid, ac_mid, C);
tesselateTriangle(ab_mid, ac_mid, bc_mid);
}
void BoundingTriangle::populateTriangleData(const std::vector<glm::vec3> &obj_data){
for (int i=0; i<obj_data.size(); i += 3){
// convert to worldspace
glm::mat4 modelMat = obj_mt->getModelMatrix();
glm::vec3 v1 = modelMat*glm::vec4(obj_data[i],1.0);
glm::vec3 v2 = modelMat*glm::vec4(obj_data[i+1],1.0);
glm::vec3 v3 = modelMat*glm::vec4(obj_data[i+2],1.0);
// make triangle
addTriangle(v1, v2, v3);
}
// m_surface_points.reserve(m_unique_surface_points.size());
// std::copy(m_unique_surface_points.begin(), m_unique_surface_points.end(), m_surface_points.begin());
}
Bounds3f BoundingTriangle::calculateTriangleBounds(const glm::vec3 &vertexA,
const glm::vec3 &vertexB,
const glm::vec3 &vertexC){
Bounds3f bounds;
float max_x, min_x = vertexA.x;
float max_y, min_y = vertexA.y;
float max_z, min_z = vertexA.z;
if (vertexB.x > max_x) max_x = vertexB.x;
if (vertexB.y > max_y) max_y = vertexB.y;
if (vertexB.z > max_z) max_z = vertexB.z;
if (vertexC.x > max_x) max_x = vertexC.x;
if (vertexC.y > max_y) max_y = vertexC.y;
if (vertexC.z > max_z) max_z = vertexC.z;
if (vertexB.x < min_x) min_x = vertexB.x;
if (vertexB.y < min_y) min_y = vertexB.y;
if (vertexB.z < min_z) min_z = vertexB.z;
if (vertexC.x < min_x) min_x = vertexC.x;
if (vertexC.y < min_y) min_y = vertexC.y;
if (vertexC.z < min_z) min_z = vertexC.z;
bounds.max = glm::vec3(max_x, max_y, max_z);
bounds.min = glm::vec3(min_x, min_y, min_z);
return bounds;
}
void BoundingTriangle::calculateBounds(const std::vector<glm::vec3> &obj_data){
max_x = obj_data[0].x;
min_x = obj_data[0].x;
max_y = obj_data[0].y;
min_y = obj_data[0].y;
max_z = obj_data[0].z;
min_z = obj_data[0].z;
for (const glm::vec3 &v : obj_data){
// check max
if (v.x > max_x){
max_x = v.x;
}
if (v.y > max_y){
max_y = v.y;
}
if (v.z > max_z){
max_z = v.z;
}
// check mins
if (v.x < min_x){
min_x = v.x;
}
if (v.y < min_y){
min_y = v.y;
}
if (v.z < min_z){
min_z = v.z;
}
}
}
Bounds3f BoundingTriangle::getMeshBounds(){
Bounds3f bounds;
bounds.max = glm::vec3(max_x, max_y, max_z);
bounds.min = glm::vec3(min_x, min_y, min_z);
return bounds;
}
std::vector<glm::vec3> BoundingTriangle::getSurfacePoints(){
if (!m_isGround){
std::cout << "getting surface points of not-ground object!" << std::endl;
}
return m_surface_points;
}
std::vector<Triangle> BoundingTriangle::getTriangleData(){
return m_triangles;
}
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