Modding tutorial/Advanced reactions

Reaction requirements

Reactions can be controlled and may be written to occur only when specific requirements are met:

Property name	Description	Reaction example
chance	Chance per tick of reaction occurring	Borax + Glue
tempMin	Minimum temperature a reaction can occur	Rock + Bone
tempMax	Maximum temperature a reaction can occur	Tuff + Charcoal
oneway	Reaction only occurs if elem1 moves into elem2	Water + Carbon Dioxide
charged	Reaction only occurs if elements are charged	Water + Zinc
burning1	Reaction only occurs if elem1 is burning	Not used
burning2	Reaction only occurs if elem2 is burning	Chlorine + Oil
"y"	Reaction only occurs at y-values within range	Steam + Snow Cloud
"setting"	Reaction only occurs if specified setting is enabled	Oxygen + Ozone

Examples of implementation include:

    reactions: {
        "chance_ex": { elem1:null, elem2:null, chance:0.5 }, // 50% chance per tick
        "temprange_ex": { elem1:null, elem2:null, tempMin:50, tempMax:100 }, // Temp must be between 50 and 100
        "oneway_ex": { elem1:null, elem2:null, oneway:true }, // Only if elem1 moves into elem2 - essentially, primary reactant must move and/or elements must be mixed
        "charged_ex": { elem1:null, elem2:null, charged:true }, // Elements must be charged
        "burning_ex": { elem1:null, elem2:null, burning1:true, burning2:true }, // elem1 and elem2 must be burning
        "height_ex": { elem1:null, elem2:null, "y":[81,71] } // Only at y-values between 81 and 71
        "setting_ex": { elem1:null, elem2:null, "setting":"clouds" } // Clouds setting must be toggled on
    },

Product properties

The properties of a reaction's product(s) can be overridden. These properties include:

Property name	Description	Reaction example
elem1	What primary reactant becomes	Almost all reactions
elem2	What secondary reactant becomes	Almost all reactions
color1	Color(s) of primary reactant	Brass + Ammonia
color2	Color(s) of secondary reactant	Dough + Milk
temp1	Temperature of primary reactant	Cloud + Electric
temp2	Temperature of secondary reactant	Neutron + Uranium
attr1	Additional attribute of primary reactant, must be applicable	Vinegar + Limestone
attr2	Additional attribute of secondary reactant, must be applicable	Yeast + Bleach

Examples of implementation include:

    reactions: {
        "elem_ex": { elem1:"water", elem2:"dirt" } // Primary reactant becomes Water, elem_ex becomes Dirt
        "color_ex": { color1:"#FFFFFF", color2:"#000000" }, // Primary reactant turns white, color_ex turns black
        "temp_ex": { temp1:500, color2:-800 }, // Primary reactant becomes 500°C, temp_ex becomes -80°C
        "attr_ex": { attr1:{"foam":20}, elem2:"sodium_acetate", attr2:{"foam":50} }, // If the primary reactant does not foam attr1 does nothing, elem2 becomes Sodium Acetate and foams
    },

The base game utilizes the "foam" attribute, which only takes effect if the reactant has a function utilizing it. For example, Sodium Acetate contains:

tick: function(pixel) {
        if ((pixel.foam || Math.random() < 0.25) && isEmpty(pixel.x,pixel.y-1)) {
            createPixel("foam",pixel.x,pixel.y-1);
            if (pixel.foam) {
                pixelMap[pixel.x][pixel.y-1].foam = pixel.foam;
                pixel.foam--;
            }
        }
    },

Where foam contributes to the amount of Foam being generated. A function similar to this can be added to any element to further customize reactions.

Functions for properties

A function can be used in a reaction statement to set any of an element's properties following the reaction. For example:

    reactions: {
        "water": {func: (pixel1) => {pixel1.burning=true;pixel1.burnStart=pixelTicks}, // Primary reactant is burning starting at current tick
            elem2: ["caustic_potash", "fire"], temp2: 400}
    }

A similar function can be written to set values for any of an element's properties, including modded ones.