How to calculate the pixel colors of an image ??

[-Bangester-]

I have an image and I'm trying to get the pixel values of the image, I want my player to collide with the image based on the value of the pixel can someone please show me how to do that and how to act upon knowing the pixels. I just thought of this idea, for me to calculate the pixel value of the entire canvas and then say if the value of a pixel was 225 then collide with it. but I want it to collide only with the image so I pretty much need to calculate the pixels of the image, but I'm not sure how to do that ... any help would be greatly appreciated

[darkfrei]

https://love2d.org/wiki/Canvas:newImageData
https://love2d.org/wiki/ImageData:getPixel
https://love2d.org/wiki/love.math.colorToBytes

[pgimeno]

Please use the Support and Development subforum for questions. This subforum is for showcasing your games and creations.

[Bigfoot71]

This can be a costly operation so here is how you could do it:

Code: Select all

local function checkCollision(img_data1,x1,y1,w1,h1, img_data2,x2,y2,w2,h2)

    -- Calculate the coordinates of the corners of the two objects
    local left1, top1, right1, bottom1 = x1, y1, x1 + w1, y1 + h1
    local left2, top2, right2, bottom2 = x2, y2, x2 + w2, y2 + h2

    -- Check if there is an intersection between the two objects

    if right1 > left2 and left1 < right2 and bottom1 > top2 and top1 < bottom2 then

        -- Calculate the intersection area between the two objects
        local intersectionLeft = math.max(left1, left2)
        local intersectionTop = math.max(top1, top2)
        local intersectionRight = math.min(right1, right2)
        local intersectionBottom = math.min(bottom1, bottom2)

        local floor = math.floor

        -- Iterate through all pixels in the intersection area
        for x = intersectionLeft, intersectionRight-1 do
            for y = intersectionTop, intersectionBottom-1 do

                -- Calculate pixel coordinates in both images
                local playerPixelX, playerPixelY = floor(x-x1), floor(y - y1)
                local obstaclePixelX, obstaclePixelY = floor(x-x2), floor(y-y2)

                -- Check if both pixels are opaque
                local _,_,_,a1 = img_data1:getPixel(playerPixelX, playerPixelY)
                local _,_,_,a2 = img_data2:getPixel(obstaclePixelX, obstaclePixelY)

                if a1 > 0 and a2 > 0 then return true end

            end
        end

    end

    return false

end

It is only as an example to get an idea, this function does not manage for example the replacement of objects following the collision, and it only works with an image origin set to 0.0. If the coordinate sent represents for example the center of the image it will also have to be modified a little.