Need help with Native Extensions(SOLVED)

Questions
#1

For me working with lua from c is some king of magic. So i need some help :grinning:
I need to iterate a color matrix and change value in stream.

Something like that but in native.

for y=1, self.height do
    local pre_calc_y = (y-1) * pre_calc
    local nodes_y = nodes[y]
        for x=1, width do
            local color = nodes_y[x]
            stream[index] = color.x * 255
            stream[index + 1] = color.y * 255
            stream[index + 2] = color.z * 255
            index = index + 3
            end
        end

colors is matrix for colors (colors[y][x] return color for pixel at (x,y))

local buffer = buffer.create(self.width * self.height, { {name=hash("rgb"), type=buffer.VALUE_TYPE_UINT8, count=3} } )
local stream  = buffer.get_stream(buffer, hash("rgb"))
native_draw.draw_pixels({width = 45, height = 60, colors = colors, stream = stream})

The problem that i don’t understand how to get value from table that is in another table.

I try start with small function.This function should convert lua array to c++ array. vmath.vector3 should be converted to int color.But i have no idea how to get x,y,z from vmath.vector3(), i get only 0.0 value

local v = vmath.vector3
local t = {v(1),v(2),v(3),v(4),v(5),v(56)}
native_draw.draw_pixels(t)

// myextension.cpp
// Extension lib defines
#define EXTENSION_NAME NativeDraw
#define LIB_NAME "NativeDraw"
#define MODULE_NAME "native_draw"

// include the Defold SDK
#include <dmsdk/sdk.h>

static double* array_to_vector(lua_State* L){
    if(lua_gettop(L) == 1 && lua_istable(L, 1))
    {
        // for each entry in the table
        size_t len = lua_objlen(L, 1);
        double *buff = (double*)malloc(len*sizeof(double));
        for(int i=1;i <= len; i++)
        {
            // get the entry to stack
            lua_pushinteger(L, i);
            lua_gettable(L, 1);

            lua_pushstring(L, "x");
            lua_gettable(L, 1);
            
            buff[i] = lua_tonumber(L, -1);
            printf("%f\n",buff[i]);
            
            printf("%f\n",lua_tonumber(L, 2));
            // remove entry from stack
            lua_pop(L,1);
        }
        return buff;
    }
    
}

static int drawPixels(lua_State* L)
{    
    array_to_vector(L);
    
    return 1;
}

// Functions exposed to Lua
static const luaL_reg Module_methods[] =
{
    {"draw_pixels", drawPixels},
    {0, 0}
};

static void LuaInit(lua_State* L)
{
    int top = lua_gettop(L);
    // Register lua names
    luaL_register(L, MODULE_NAME, Module_methods);
    lua_pop(L, 1);
    assert(top == lua_gettop(L));
}

dmExtension::Result AppInitializeMyExtension(dmExtension::AppParams* params)
{
    return dmExtension::RESULT_OK;
}

dmExtension::Result InitializeMyExtension(dmExtension::Params* params)
{
    // Init Lua
    LuaInit(params->m_L);
    printf("Registered %s Extension\n", MODULE_NAME);
    return dmExtension::RESULT_OK;
}

dmExtension::Result AppFinalizeMyExtension(dmExtension::AppParams* params)
{
    return dmExtension::RESULT_OK;
}

dmExtension::Result FinalizeMyExtension(dmExtension::Params* params)
{
    return dmExtension::RESULT_OK;
}

DM_DECLARE_EXTENSION(EXTENSION_NAME, LIB_NAME, AppInitializeMyExtension, AppFinalizeMyExtension, InitializeMyExtension, 0, 0, FinalizeMyExtension)
#2

For the sake of simplicity I’d use a one dimensional array. Less messy on the C end.

2 Likes
#3

Solved

3 Likes