Development PHP "raycaster" 3D renderer

[NiHiLiST]

I mentioned recently that I was looking for an interesting PHP project. This evening I remembered an idea I had a while ago to make a 3D renderer in PHP (and if anyone's tempted to ask - "because I can" ). I did a bit of reading on old 3D engines, as I didn't want something modern and slow, and found out that the "raycaster" rendering used in Wolfenstein 3D is ridiculously easy to implement. A few hours later and it's up and running I've not run any proper speed tests yet, but the images load up pretty much instantaneously. I have a couple of ideas of what this could be used for, so watch this space

Sample render:


Works off axis too of course:


And on the vertical:


The code is currently just over 300 lines long. It could be compressed down a lot (maybe even to half it's current size) just to show how stupidly simple things are with PHP. It will bulk out marginally once I get all of the functions in place for setting up the render size, camera position, angle, FOV etc as they are currently all just variables set in __construct. Even the map is just being randomly generated and thrown in.

Next real things to do will be to expand the texture mapping somewhat (at the moment it's just 1 for each of walls, floor and ceiling) and get it showing sprites. Then maybe HDR and anisotropic filtering

[JazzXP]

Wow, that's awesome. That could be used for some great stuff. 3d website, HTML based RPG, stuff like that!

[hitman012]

Wow - very nice work! Reminds me of the 3D Maze screensaver that you used to get with Win95

[Nath]

Awesome, can't wait to see what you get up to with this!

[NiHiLiST]

Thanks, Jazz. I did consider it could be used to add some visual depth to those HTML-based RPG games. Would be pretty easy to do, but until I've run some load tests I couldn't say how it would affect the server, it might get pretty intensive if the site's getting a lot of hits.

One of the big overheads at the moment is that the textures have to be loaded from disk each time, and there are a lot of sin/cos/tan calculations. It's currently using lookup tables for those, but again, it's having to either generate or load those each time the script runs so some persistent memory or suchlike may need to be looked at

Of course if you wanted this kind of thing on a large site it would make more sense to just code the renderer in C or something and have your scripts execute the program when necessary. PHP's not bad for things like this, but it's far from being the fastest.

[NiHiLiST]

Eeee, 2 more replies whilst I was writing my last one Thanks hitman, Nath.

[RTT]

Surely you're loading .dlls and just calling functions from within the DLL using PHP?

I'm not denying that it's cool - it is - but if i'm right then PHP isn't doing the fun stuff

Please tell me I'm 110% wrong!

[NiHiLiST]

No I'm not, RTT, that would be silly The only thing I'm using is mathematical functions, binary operators and the GD library. No extensions, no DLLs, just classic software rendering.

[RTT]

Cor blimey Color me impressed!

[NiHiLiST]

Here are the functions used RTT :
require_once
mt_rand
sin
cos
tan
pi
sqrt
pow
imagecreatetruecolor
imagecreatefrompng
imagecopy
imagedestroy
imagepng
imagecolorat
imagesetpixel
header

Plus of course the functions in the class I've written.

[RotoSequence]

Add sprites!

[NiHiLiST]

Originally Posted by RotoSequence

Add sprites!

Right now I'm going to bed, but maybe tonight (Friday) I'll get a chance to, if I'm not out pimping of course

[RTT]

Originally Posted by NiHiLiST

Here are the functions used RTT :
...

require_once aint a function

Hehe... can't wait for updates on this. Some source wouldn't go amiss either /curious

[Fusen]

some source and a demo would be awesome ;D

[FredsFriend]

This is teh funkey, seconded on the intrest ub the source it would be interesting to look through.

[NiHiLiST]

Originally Posted by RTT

require_once aint a function

Hehe... can't wait for updates on this. Some source wouldn't go amiss either /curious

True, I was tired - functions and language constructs blur into one when it's bedtime

[NiHiLiST]

Code for those who were asking:

PHP Code:

    public function render() {
        
        // find which map block the camera is in
        
        $cameraBlockX = $this->camX >> 6;
        $cameraBlockY = $this->camY >> 6;

        $offset = 0;

        // clamp angle for lookup tables

        if ($this->camAngle < 0)        $this->camAngle += pi() * 2;
        if ($this->camAngle > pi() * 2) $this->camAngle -= pi() * 2;

        $angle = $this->camAngle + $this->camFov * 0.5;
        if ($angle > pi() * 2) $angle -= pi() * 2;
        
        $width = $this->width;

        $this->camPCentre = $this->height / 2 - $this->camRoll;
            
        $ang = ($this->camAngle * $this->divisor) | 0;
        
        $invertZ = 64 - $this->camZ;

        // loop through each vertical strip

        while ($width-- > 0) {

            // set nearest face to practical infinity

            $nearestFace = 4294967296;

            $angleLookup = ($angle * $this->divisor);

            // find oriented face aligned to X axis of map

            $x = $cameraBlockX;
            $y = $cameraBlockY;

            if ($this->sin[$angleLookup] < 0) {

                while ($y > -1 && $x > -1 && $x < $this->mapWidth) {
                    $absY = $y << 6;
                    $absX = $this->camX + ($absY - $this->camY) / $this->tan[$angleLookup];
                    $x    = $absX >> 6;

                    // check if there is a block here

                    if ($this->map[$x][--$y]) {
                        $nearestFace = pow($absX - $this->camX, 2) + pow($absY - $this->camY, 2);
                        $offset = $absX & 63;
                        break;
                    }
                }

            } else {

                while ($y++ < $this->mapHeight && $x > -1 && $x < $this->mapWidth) {
                    $absY = $y << 6;
                    $absX = $this->camX + ($absY - $this->camY) / $this->tan[$angleLookup];
                    $x    = $absX >> 6;
                    
                    // check if there is a block here
                    
                    if ($this->map[$x][$y]) {
                        $nearestFace = pow($absX - $this->camX, 2) + pow($absY - $this->camY, 2);
                        $offset = 64 - $absX & 63;
                        break;
                    }
                }

            }

            // find closest face oriented to Y axis of map

            $x = $cameraBlockX;
            $y = $cameraBlockY;

            if ($this->cos[$angleLookup] < 0) {

                while ($x > -1 && $y > -1 && $y < $this->mapHeight) {
                    $absX = $x << 6;
                    $absY = $this->camY + ($absX - $this->camX) * $this->tan[$angleLookup];
                    $y    = $absY >> 6;
                    
                    // check if there is a block here

                    if ($this->map[--$x][$y]) {
                        $distance = pow($absX - $this->camX, 2) + pow($absY - $this->camY, 2);

                        if ($distance < $nearestFace) {
                            $nearestFace = $distance;
                            $offset = 64 - $absY & 63;
                        }
                        break;
                    }
                }

            } else {

                while ($x++ < $this->mapWidth && $y > -1 && $y < $this->mapHeight) {
                    $absX = $x << 6;
                    $absY = $this->camY + ($absX - $this->camX) * $this->tan[$angleLookup];
                    $y    = $absY >> 6;
                    
                    // check if there is a block here
                    
                    if ($this->map[$x][$y]) {
                        $distance = pow($absX - $this->camX, 2) + pow($absY - $this->camY, 2);

                        if ($distance < $nearestFace) {
                            $nearestFace = $distance;
                            $offset = $absY & 63;
                        }
                        break;
                    }
                }

            }

            // check whether the current strip is looking left or right of centre angle

            if ($angleLookup < $ang)    {
                $distort = $this->camDistance / $this->cos[7200 + $angleLookup - $ang];
            } else {
                $distort = $this->camDistance / $this->cos[$angleLookup - $ang];
            }

            $wallHeight = $distort / sqrt($nearestFace);

            $distanceFloor   = $invertZ * $distort;
            $distanceCeiling = $this->camZ * $distort;

            $floorLevel = (int) ($this->camPCentre + $wallHeight * $this->camZ + 0.5);
            $wallLevel  = (int) ($this->camPCentre - $wallHeight * $invertZ);

            $height = $this->height;

            // draw floor

            while (--$height > $floorLevel && $height >= 0) {
                $distance = $distanceFloor / ($height - $this->camPCentre);
                imagesetpixel($this->canvas, $width, $height, imagecolorat($this->texFloor, ($this->camX + $this->cos[$angleLookup] * $distance) & 63, ($this->camY + $this->sin[$angleLookup] * $distance) & 63));
            }

            // draw wall

            while (--$height > $wallLevel && $height >= 0) {
                imagesetpixel($this->canvas, $width, $height, imagecolorat($this->texWall, $offset, ($height - $wallLevel) / $wallHeight));
            }

            // draw ceiling

            while (--$height > -1) {
                $distance = $distanceCeiling / ($this->camPCentre - $height);
                imagesetpixel($this->canvas, $width, $height, imagecolorat($this->texCeil, ($this->camX + $this->cos[$angleLookup] * $distance) & 63, ($this->camY + $this->sin[$angleLookup] * $distance) & 63));
            }

            $angle -= $this->camPerRayAngle;
            
            if ($angle < 0) $angle += pi() * 2;
        }
    } 


The rest of the class needs some work before it's really presentable

[Hwulex]

Wow, very impressive. I wouldn't even know where to begin with soemthing like this.

Damn I hate sucking at math.

[korhojoa]

Whoa, VERY Nice!
(Oh yes, and you got dugg.)

[Rexxie]

That's pretty awesome. Nice work!

Oh and yeah, you got dugg