void VisSurface::build(){
sharedInfo->release();
glGenBuffers(1, &(sharedInfo->vtx_buf_id));
glGenBuffers(1, &(sharedInfo->idx_buf_id));
glBindBuffer(GL_ARRAY_BUFFER, sharedInfo->vtx_buf_id);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, sharedInfo->idx_buf_id);
//prepare for data generation
Vec2i dicing = sharedInfo->dicing;
Vec2d dicingf = Vec2d(dicing.x - 1, dicing.y - 1);
int num_floats = dicing.x * dicing.y * 3;
int num_idxs = dicing.x * (dicing.y-1) * 2;
float *vtxData = new float[num_floats];
unsigned int *idxData = new unsigned int[num_idxs];
//generate pt data
for (int y = 0; y < dicing.y; y++){
for (int x = 0; x < dicing.x; x++){
Vec2d st = sharedInfo->region.remap(Vec2d(x,y) / dicingf);
Vec3d pt = surface->eval(st);
unsigned int vtx_num = (unsigned int)(dicing.x) * y + x;
vtxData[3*vtx_num] = pt.x;
vtxData[3*vtx_num+1] = pt.y;
vtxData[3*vtx_num+2] = pt.z;
if (y < dicing.y - 1){
idxData[vtx_num * 2] = vtx_num;
idxData[vtx_num * 2 + 1] = vtx_num + dicing.x;
}
}
}
//TODO: normals (interleave; it's better)
//send the data
glBufferData(GL_ARRAY_BUFFER, sizeof(float) * num_floats, vtxData, GL_STATIC_DRAW);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(int) * num_idxs, idxData, GL_STATIC_DRAW);
sharedInfo->valid = true;
delete [] vtxData;
delete [] idxData;
}
