lots of random code, usually involving the drawing of a teapot.
TEMPLATE = lib CONFIG+=staticlib
#include "SDL.h"
#include <GLES2/gl2.h>
#define GL_GLEXT_PROTOTYPES 1
#include <GLES2/gl2ext.h>
#include <emscripten.h>
#include <iostream>
#include <cstdlib>
void process()
{
// as we don't have a timer we need to do something here
// using a static to update at an interval
static int t=0;
if(++t > 100)
{
float r=(double)rand() / ((double)RAND_MAX + 1);
float g=(double)rand() / ((double)RAND_MAX + 1);
float b=(double)rand() / ((double)RAND_MAX + 1);
glClearColor(r,g,b,1);
t=0;
}
glClear(GL_COLOR_BUFFER_BIT);
// this is where we draw
SDL_GL_SwapBuffers();
}
int main(int argc, char *argv[])
{
SDL_Surface *screen;
// Init SDL
if ( SDL_Init(SDL_INIT_VIDEO) != 0 )
{
std::cerr<<"Unable to initialize SDL: "<<SDL_GetError();
return EXIT_FAILURE;
}
SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
screen = SDL_SetVideoMode( 720, 576, 16, SDL_OPENGL | SDL_RESIZABLE);
if ( !screen )
{
std::cerr<<"Unable to set video mode: "<<SDL_GetError();
return EXIT_FAILURE;
}
glEnable(GL_DEPTH_TEST);
// let emscripten process something then
// give control back to the browser
emscripten_set_main_loop (process, 0, true);
SDL_Quit();
return EXIT_SUCCESS;
}
The emscripten_set_main_loop function is explained very well here basically we create a function that is called asynchronously to allow the browser to regain control after every iteration of the function. It is important that this function does exit else the browser will hang up and I have had several times when I get a complete lockup of the system.
em++ -s FULL_ES2=1 SDL1.cpp -o SDL1.htmlThe flag -s FULL_ES2 tells emscripten to use full OpenGL ES 2 specification when compiling the code, the -o SDL1.html will generate an html file as well as the javascript file for the canvas to use. The html file can now be opened in the browser an in this case you will see a screen that changes colour every 100 cycles of the main loop. In the next post I will begin to discuss how I ported the rest of ngl to use emscripten.
alias ls='ls --color' alias ll='ls -al' alias rm='rm -i'
INCLUDEPATH+=/usr/local/alembic-1.0.3/include/ INCLUDEPATH+=/usr/local/include/OpenEXR LIBS+=-L/usr/local/alembic-1.0.3/lib/static/ LIBS+=-lAlembicAbc LIBS+=-lAlembicAbcGeom LIBS+=-lAlembicAbcCoreAbstract LIBS+=-lAlembicUtil LIBS+=-lAlembicAbcCoreHDF5 LIBS+=-lImath LIBS+=-lHalf LIBS+=-lIex LIBS+=-lhdf5 LIBS+=-lhdf5_hl
#include <Alembic/AbcGeom/All.h> #include <Alembic/AbcCoreAbstract/All.h> #include <Alembic/AbcCoreHDF5/All.h> #include <Alembic/Abc/ErrorHandler.h> using namespace Alembic::AbcGeom; ...
IArchive archive( Alembic::AbcCoreHDF5::ReadArchive(),argv[1] );
std::cout<<"traversing archive for elements\n"; IObject obj=archive.getTop(); unsigned int numChildren=obj.getNumChildren(); std::cout<< "found "<<numChildren<<" children in file\n";Once we have the number of children we can iterate for each child in the node and traverse the tree (it must be noted in this example I know the tree is of a set depth, in reality we would need to traverse using recursion / visitor pattern to cope with more complex scene / geometry data however for a proof of concept this is fine)
for(int i=0; i<numChildren; ++i)
{
std::cout<<obj.getChildHeader(i).getFullName()<<"\n";
IObject child(obj,obj.getChildHeader(i).getName());
std::cout<<"Children "<<child.getNumChildren()<<"\n";
const MetaData &md = child.getMetaData();
std::cout<<md.serialize() <<"\n";
for(int x=0; x<child.getNumChildren(); x++)
{
IObject child2(child,child.getChildHeader(x).getName());
const MetaData &md2 = child2.getMetaData();
if( IPolyMeshSchema::matches( md2 ) || ISubDSchema::matches( md2 ))
{
std::cout<<"Found a mesh "<<child2.getName()<<"\n";
}
}
}
The code above grabs the child header of the current object and prints out the name. We then create a new IObject from the current object branch (getChildHeader(i).getName() ), this is the next object in the tree and we can then traverse this.IXform x( child, kWrapExisting ); XformSample xs; x.getSchema().get( xs ); M44d mat=xs.getMatrix();
// we have a mesh so build a mesh object IPolyMesh mesh(child,child2.getName()); // grab the schema for the object IPolyMeshSchema schema=mesh.getSchema(); // now grab the time sample data for the object IPolyMeshSchema::Sample mesh_samp; schema.get( mesh_samp ); // get how many points (positions) there are uint32_t size=mesh_samp.getPositions()->size();
for(uint32_t m=0; m<size; ++m)
{
// get the current point
V3f p= mesh_samp.getPositions()->get()[m];
// multiply by transform p=p*mat; // store for later use data.push_back(ngl::Vec3(p.x,p.y,p.z)); }In the case of this demo I just create a point cloud into a Vertex Array object and draw using my ngl:: framework. This can be seen in the following video