#include <iostream>

#include "sre/SDLRenderer.hpp"

#include "sre/SpriteAtlas.hpp"

#include "sre/Texture.hpp"

#include "sre/Material.hpp"

#include "sre/Inspector.hpp"

#include "glm/gtc/random.hpp"

#define GLM_ENABLE_EXPERIMENTAL

#include "glm/gtx/transform.hpp"

#include "glm/ext.hpp"

// lua headers

#include "sol.hpp"

using namespace sre;

using namespace std;

using namespace sol;

class LuaExample {

public:

LuaExample()

{

r.init();

r.setWindowTitle("Lua example");

objPosition = {5.5f,0,0};

mat = Shader::getUnlit()->createMaterial();

mat->setColor({1,0,0,1});

mesh = Mesh::create().withSphere().build();

lua.open_libraries(sol::lib::base, sol::lib::package, sol::lib::math);

// Register callback functions

lua.set_function("pi", [&](sol::this_state state, sol::variadic_args va){

return glm::pi<double>();

});

lua.set_function("fmod", [&](sol::this_state state, sol::variadic_args va){

double numer = va[0];

double denum = va[1];

return fmod(numer,denum);

});

lua.set_function("remainder", [&](sol::this_state state, sol::variadic_args va){

double s = va[0];

double denum = va[1];

return remainder(s,denum);

});

lua.set_function("abs", [&](sol::this_state state, sol::variadic_args va){

double s = va[0];

return abs(s);

});

lua.set_function("sin", [&](sol::this_state state, sol::variadic_args va){

double s = va[0];

return sin(s);

});

lua.set_function("cos", [&](sol::this_state state, sol::variadic_args va){

double s = va[0];

return cos(s);

});

lua.set_function("pow", [&](sol::this_state state, sol::variadic_args va){

double s = va[0];

double p = va[1];

return pow(s,p);

});

updateLuaScript();

// init objects

for (float x = -5;x<=5;x=x+0.01f){

positions.push_back({x,0,0});

}

camera.setOrthographicProjection(5,-1,1);

r.frameUpdate = [&](float deltaTime){

update(deltaTime);

};

r.frameRender = [&](){

render();

};

r.startEventLoop();

}

void updateLuaScript() {

lua.script(luaScript); // evaluate lua script

sol::function fn = lua["easing"]; // get lua function update pos

updatepos = fn; // get C++ functional reference to lua script

}

void update(float deltaTime){

static float totalTime = 0;

totalTime += deltaTime;

try {

if (error.size()==0){

objPosition.y = (float) updatepos(totalTime);

}

} catch (sol::error err){

error = err.what();

}

}

void render(){

try {

if (error.size()==0){

int i = 0;

for (float x = -5; x <= 5; x = x + 0.01f) {

positions[i] = {x, (float) updatepos(x), 0};

i++;

}

}

} catch (sol::error err){

error = err.what();

}

RenderPass rp = RenderPass::create()

.withCamera(camera)

.build();

// draw grid

for (int i=-5;i<=5;i++){

Color color = (i==0?Color{1.0f,1.0f,1.0f,1.0f}:Color{0.2f,0.2f,0.2f,1.0f});

rp.drawLines({{i,-5,0},{i,5,0}},color, MeshTopology::LineStrip);

rp.drawLines({{-5,i,0},{5,i,0}},color, MeshTopology::LineStrip);

}

rp.drawLines(positions,{1.0,1.0,1.0,1.0}, MeshTopology::LineStrip);

rp.draw(mesh, glm::translate(objPosition)*glm::scale(glm::vec3{0.5f,0.5f,0.5f}), mat);

ImGui::InputTextMultiline("Lua script", luaScript , luaScriptSize);

if (error.size() > 0){

ImGui::LabelText("Error", error.c_str());

}

if (ImGui::Button("Update")){

try {

updateLuaScript();

error = "";

} catch (sol::error err){

error = err.what();

}

}

}

private:

static const int luaScriptSize = 2048;

// initial script

char luaScript[luaScriptSize] =

"-- C functions exposed:\n"

"-- fmod(a,b), remainder(a,b), abs(a), sin(a), cos(a), pow(a), pi()\n"

"function easing (t) \n"

" return t \n"

"end";

std::vector<glm::vec3> positions;

glm::vec3 objPosition;

std::shared_ptr<sre::Mesh> mesh;

std::shared_ptr<sre::Material> mat;

SDLRenderer r;

Camera camera;

std::string error;

sol::state lua;

std::function<double(double)> updatepos;

};

int main() {

std::cout << "https://github.com/mortennobel/SimpleRenderEngineProject" << std::endl;

new LuaExample();

return 0;

}