Files
Enzo/src/Gui/Viewport/GLMesh.cpp

165 lines
4.0 KiB
C++

#include "Gui/Viewport/GLMesh.h"
#include <GL/gl.h>
#include <iostream>
#include "Engine/Operator/AttributeHandle.h"
#include "Engine/Operator/Geometry.h"
#include "Engine/Types.h"
#include <CGAL/Polygon_mesh_processing/compute_normal.h>
#include "icecream.hpp"
GLMesh::GLMesh()
{
initializeOpenGLFunctions();
init();
}
void GLMesh::init()
{
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
initBuffers();
// store data in the buffer
// glBufferData(GL_ARRAY_BUFFER, vertexPosData.size()*sizeof(GLfloat), vertexPosData.data(), GL_STATIC_DRAW);
// glBufferData(GL_ELEMENT_ARRAY_BUFFER, indexData.size()*sizeof(GLint), indexData.data(), GL_STATIC_DRAW);
// unbind vertex array
glBindVertexArray(0);
}
void GLMesh::initBuffers()
{
// create buffer of vertices
glGenBuffers(1, &vertexBuffer);
// set purpose
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
// gives the shader a way to read buffer data
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)0);
// read normal
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, normal));
// disable vertex attrib array
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glGenBuffers(1, &indexBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
}
void GLMesh::setPosBuffer(enzo::geo::Geometry& geometry)
{
bind();
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
const size_t numPrims = geometry.getNumPrims();
vertices.resize(geometry.getNumVerts());
for (int primOffset=0; primOffset<numPrims; ++primOffset)
{
const unsigned int primStartVert = geometry.getPrimStartVertex(primOffset);
auto faceIndex = primOffset;
int faceVertCnt = geometry.getPrimVertCount(primOffset);
enzo::bt::Vector3 n;
// compute normal
if(faceVertCnt>=3)
{
const unsigned v1 = primStartVert;
const unsigned v2 = primStartVert + 1;
const unsigned v3 = primStartVert + 2;
const enzo::bt::Vector3 pos1 = geometry.getPosFromVert(v1);
const enzo::bt::Vector3 pos2 = geometry.getPosFromVert(v2);
const enzo::bt::Vector3 pos3 = geometry.getPosFromVert(v3);
enzo::bt::Vector3 tang1 = (pos2-pos1);
enzo::bt::Vector3 tang2 = (pos3-pos1);
tang1.normalize();
tang2.normalize();
n = tang1.cross(tang2);
}
for(int i=0; i< faceVertCnt; ++i)
{
const unsigned int vertexCount = primStartVert+i;
enzo::bt::Vector3 p = geometry.getPosFromVert(vertexCount);
vertices[vertexCount] ={
{ p.x(),
p.y(),
p.z()},
{ n.x(),
n.y(),
n.z()}
};
}
}
glBufferData(GL_ARRAY_BUFFER, vertices.size()*sizeof(Vertex), vertices.data(), GL_STATIC_DRAW);
unbind();
}
void GLMesh::setIndexBuffer(std::vector<int> pointIndices, std::vector<int> primVertexCounts)
{
bind();
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
indexData.clear();
unsigned int startVert = 0;
// create triangle fan from potentially ngon inputs
for(size_t primNum=0; primNum<primVertexCounts.size(); ++primNum)
{
int primVertexCount = primVertexCounts[primNum];
for(size_t i=1; i<primVertexCount-1; ++i)
{
indexData.push_back(startVert);
indexData.push_back(startVert+i);
indexData.push_back(startVert+i+1);
}
startVert += primVertexCount;
}
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indexData.size()*sizeof(GLint), indexData.data(), GL_STATIC_DRAW);
unbind();
}
void GLMesh::bind()
{
glBindVertexArray(vao);
}
void GLMesh::unbind()
{
glBindVertexArray(0);
}
void GLMesh::draw()
{
bind();
// wireframe
// glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
glDrawElements(GL_TRIANGLES, indexData.size(), GL_UNSIGNED_INT, 0);
}