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Raycasting Engine
Back in 1997, I wrote a raycasting engine in Turbo Pascal. It had a number of features and was heading towards being turned into a fully fledged game engine. That never happened. But since then, as I move between development platforms, I like to port a cutdown version of it to help make me familiar with the syntax and API on the new platform. Here is a basic raycasting engine written in LUA with the Corona SDK.
This demo only contains flat filled walls and simple movement controls (with wall clipping). Expanding on it however is not difficult to add secret walls, doors, items, etc.
I have kept optimisation minimal, keeping only to look up tables in most cases to get some performance boost.
Porting it was easier than I had expected, and if I get some time, I will return and add more features.
Here are the files you will need:
config.lua
1 2 3 4 5 6 7 8 9 | application = { content = { width = 320, height = 480, scale = 'letterbox' }, } |
build.settings
1 2 3 4 5 6 7 8 9 10 11 | settings = { orientation = { default = "landscapeRight", supported = { "landscapeLeft", "landscapeRight", }, }, } |
map.lua
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 | -- Project: Raycasting Engine Demo -- SDK: Corona - 09/12/11 -- Author: Andrew Burch -- Date: 08/02/2012 -- Site: http://www.newhighscore.net -- Contact: andrew.burch@newhighscore.net -- Note: Map data and variables module(..., package.seeall) rowCount = 10 columnCount = 10 mapData = { {1,2,3,4,1,2,3,4,1,1}, {1,0,0,4,0,0,0,0,0,2}, {2,0,0,2,2,0,0,0,3,3}, {3,0,0,5,0,0,0,0,0,2}, {2,0,0,1,2,3,1,0,0,4}, {1,0,0,0,4,0,0,0,0,2}, {2,0,0,0,5,0,0,0,5,3}, {3,3,0,0,0,0,0,0,0,2}, {2,0,0,0,2,0,0,3,0,1}, {1,1,2,3,2,1,2,3,2,1}, } wallDefList = { { textureId = 'wall1', isSolid = true, }, { textureId = 'wall2', isSolid = true, }, { textureId = 'wall3', isSolid = true, }, { textureId = 'wall4', isSolid = true, }, { textureId = 'wall5', isSolid = true, }, } |
input.lua
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 | -- Class: Input Handler -- SDK: Corona - 09/12/11 -- Author: Andrew Burch -- Date: 08/02/12 -- Site: http://www.newhighscore.net -- Contact: andrew.burch@newhighscore.net -- Note: Process touch events to handle input for the camera -- Very custom to the raycasting engine demo local abs = math.abs local max = math.max local min = math.min local Input = {} local Input_mt = {__index = Input} function Input.new(params) local displayGroup = display.newGroup() local input = { displayGroup = displayGroup, } return setmetatable(input, Input_mt) end function Input:initialise(params) local displayGroup = self.displayGroup local displayWidth = params.displayWidth local buttonWidth = params.buttonWidth local buttonHeight = params.buttonHeight local sideBorder = params.sideBorder local turnAcceleration = params.turnAcceleration local movementAcceleration = params.movementAcceleration local rightButtonSetX = displayWidth - sideBorder - buttonWidth local phaseStateMap = { ['began'] = true, ['moved'] = true, ['ended'] = false, ['cancelled'] = false, } local buttonConfig = { { x = sideBorder, y = 240, modifierName = 'turnAcceleration', modiferValue = -turnAcceleration, stateName = 'isTurning', }, { x = 80, y = 240, modifierName = 'turnAcceleration', modiferValue = turnAcceleration, stateName = 'isTurning', }, { x = rightButtonSetX, y = 200, modifierName = 'movementAcceleration', modiferValue = movementAcceleration, stateName = 'isMoving', }, { x = rightButtonSetX, y = 260, modifierName = 'movementAcceleration', modiferValue = -movementAcceleration, stateName = 'isMoving', }, } for _, v in ipairs(buttonConfig) do local button = display.newRoundedRect(displayGroup, v.x, v.y, buttonWidth, buttonWidth, 4) button.strokeWidth = 2 button:setFillColor(140, 140, 140, 100) button:setStrokeColor(180, 180, 180, 100) button:addEventListener('touch', function(event) local phase = event.phase local state = phaseStateMap[phase] local modifierName = v.modifierName local modiferValue = v.modiferValue local stateName = v.stateName self[modifierName] = state and modiferValue or nil self[stateName] = state return true end) end self.movementSpeed = 0 self.turnSpeed = 0 end function Input:update(dt, time, params) local isMoving = self.isMoving local movementSpeed = self.movementSpeed if isMoving then local movementAcceleration = self.movementAcceleration local maxMovementSpeed = params.maxMovementSpeed local newSpeed = movementSpeed + movementAcceleration newSpeed = max(min(newSpeed, maxMovementSpeed), -maxMovementSpeed) self.movementSpeed = newSpeed end if not isMoving and movementSpeed ~= 0 then local moveDeccelerateFactor = params.moveDeccelerateFactor local newSpeed = movementSpeed * moveDeccelerateFactor if abs(newSpeed) < 0.1 then newSpeed = 0 end self.movementSpeed = newSpeed end local isTurning = self.isTurning local turnSpeed = self.turnSpeed if isTurning then local turnAcceleration = self.turnAcceleration local maxTurnSpeed = params.maxTurnSpeed local newSpeed = turnSpeed + turnAcceleration newSpeed = max(min(newSpeed, maxTurnSpeed), -maxTurnSpeed) self.turnSpeed = newSpeed end if not isTurning and turnSpeed ~= 0 then local turnDeccelerateFactor = params.turnDeccelerateFactor local newSpeed = turnSpeed * turnDeccelerateFactor if abs(newSpeed) < 0.1 then newSpeed = 0 end self.turnSpeed = newSpeed end end function Input:getTurnSpeed() return self.turnSpeed end function Input:getMovementSpeed() return self.movementSpeed end return Input |
renderer.lua
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | -- Class: Renderer -- SDK: Corona - 09/12/11 -- Author: Andrew Burch -- Date: 08/02/12 -- Site: http://www.newhighscore.net -- Contact: andrew.burch@newhighscore.net -- Note: Render a single frame from the raycasting engine -- Very custom and unoptimised -- Only handles flat filled walls - no textures (..yet) local tablex = require('tablex') local floor = math.floor local min = math.min -- basic depth shading local shadeDistanceMax = 500 local shadeConst = 1 / shadeDistanceMax local colourTable = { {r = 140, g = 0, b = 0}, {r = 0, g = 140, b = 0}, {r = 0, g = 90, b = 140}, {r = 90, g = 0, b = 140}, {r = 90, g = 140, b = 0}, } local Renderer = {} local Renderer_mt = {__index = Renderer} function Renderer.new(params) local displayGroup = display.newGroup() local referencePoint = display.TopLeftReferencePoint displayGroup:setReferencePoint(referencePoint) local renderer = { displayGroup = displayGroup, } return setmetatable(renderer, Renderer_mt) end function Renderer:initialise(params) local displayGroup = self.displayGroup local displayWidth = params.displayWidth local columnWidth = params.columnWidth local horizon = params.horizon local referencePoint = display.TopLeftReferencePoint local renderTable = {} for i = 0, displayWidth do local slice = display.newRect(i - 1, horizon, columnWidth, 0) slice:setFillColor(0, 0, 0) slice:setReferencePoint(referencePoint) table.insert(renderTable, slice) end self.renderTable = renderTable end function Renderer:renderScene(params) local renderTable = self.renderTable local horizon = params.horizon local sceneInfo = params.sceneInfo for i, sliceInfo in ipairs(sceneInfo) do local sliceHeight = sliceInfo.sliceHeight local halfSliceHeight = sliceHeight local renderSlice = renderTable[i] renderSlice.height = sliceHeight local colourId = sliceInfo.wallId local col = colourTable[colourId] local distance = sliceInfo.distance local shadeFactor = 1 - (min(distance, shadeDistanceMax) * shadeConst) local r = col.r * shadeFactor local g = col.g * shadeFactor local b = col.b * shadeFactor renderSlice:setFillColor(r, g, b) end end return Renderer |
raycast.lua
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 | -- Class: Raycast Engine -- SDK: Corona - 09/12/11 -- Author: Andrew Burch -- Date: 08/02/12 -- Site: http://www.newhighscore.net -- Contact: andrew.burch@newhighscore.net -- Note: Basic raycasting engine - minimal feature set -- minor optimisation local floor = math.floor local ceil = math.ceil local min = math.min local abs = math.abs local rad = math.rad local tan = math.tan local cos = math.cos local sin = math.sin local MAX_DISTANCE = 99999 local RaycastEngine = {} local RaycastEngine_mt = {__index = RaycastEngine} function RaycastEngine.new(params) local engine = { } return setmetatable(engine, RaycastEngine_mt) end function RaycastEngine:initialise(params) local visibleWidth = params.visibleWidth local visibleHeight = params.visibleHeight local mapRowCount = params.mapRowCount local mapColumnCount = params.mapColumnCount local fov = params.fov local mapCellSize = params.mapCellSize local halfFov = fov * 0.5 local halfVisibleWidth = visibleWidth * 0.5 local distanceConst = halfVisibleWidth / tan(rad(halfFov)) local angleStep = fov / visibleWidth local angleCount = ceil(360 / angleStep) -- build common angles table local commonAngleList = params.commonAngleList local commonAngles = {} for _, angle in ipairs(commonAngleList) do commonAngles[angle] = floor((angleCount / 360) * angle) end -- build slice height look up table local heightTableSize = ceil((mapCellSize * mapRowCount) / sin(rad(45))) local heightTable = {} for i = 1, heightTableSize do local sliceHeight = (mapCellSize / i) * distanceConst heightTable[i] = floor(sliceHeight) end -- build intercept and math tables local xNextTable = {} local yNextTable = {} local cosTable = {} local sinTable = {} local tanTable = {} local invalidAngles = { [commonAngles[0]] = true, [commonAngles[90]] = true, [commonAngles[180]] = true, [commonAngles[270]] = true, [commonAngles[360]] = true, } local nextAngle = 0 for i = 0, angleCount + 1 do local angleRad = rad(nextAngle) if invalidAngles[i] then tanTable[i] = 0 xNextTable[i] = 0 yNextTable[i] = 0 else local angleTan = tan(angleRad) tanTable[i] = angleTan xNextTable[i] = mapCellSize / angleTan yNextTable[i] = mapCellSize * angleTan end local angle = (i * math.pi) / commonAngles[180] cosTable[i] = cos(angle) sinTable[i] = sin(angle) nextAngle = nextAngle + angleStep end self.foundWalls = {} self.mapCellSize = mapCellSize self.mapColumnCount = mapColumnCount self.mapRowCount = mapRowCount self.heightTable = heightTable self.commonAngles = commonAngles self.xNextTable = xNextTable self.yNextTable = yNextTable self.cosTable = cosTable self.sinTable = sinTable self.tanTable = tanTable end function RaycastEngine:getFirstHorizontalIntercept(xpos, ypos, rayAngle) local commonAngles = self.commonAngles local mapCellSize = self.mapCellSize local xNextTable = self.xNextTable local tanTable = self.tanTable local rayInfo = { x = 0, y = 0, } local rayPast180 = rayAngle > commonAngles[180] local yModifier = rayPast180 and -1 or mapCellSize rayInfo.y = (floor(ypos / mapCellSize) * mapCellSize) + yModifier local invalidAngles = { [commonAngles[90]] = true, [commonAngles[270]] = true, } local invalidAngle = invalidAngles[rayAngle] rayInfo.x = invalidAngle and xpos or (xpos + (rayInfo.y - ypos) / tanTable[rayAngle]) rayInfo.rayYStep = rayPast180 and -mapCellSize or mapCellSize rayInfo.rayXStep = rayPast180 and -xNextTable[rayAngle] or xNextTable[rayAngle] return rayInfo end function RaycastEngine:getFirstVerticalIntercept(xpos, ypos, rayAngle) local commonAngles = self.commonAngles local mapCellSize = self.mapCellSize local yNextTable = self.yNextTable local tanTable = self.tanTable local rayInfo = { x = 0, y = 0, } local rayFacingDown = rayAngle > commonAngles[90] and rayAngle < commonAngles[270] local xModifier = rayFacingDown and -1 or mapCellSize rayInfo.x = (floor(xpos / mapCellSize) * mapCellSize) + xModifier rayInfo.y = ypos + (rayInfo.x - xpos) * tanTable[rayAngle] rayInfo.rayYStep = rayFacingDown and -yNextTable[rayAngle] or yNextTable[rayAngle] rayInfo.rayXStep = rayFacingDown and -mapCellSize or mapCellSize return rayInfo end function RaycastEngine:performHorizontalCheck(xpos, ypos, rayAngle, worldMap, wallDefList, rayInfo) local mapColumnCount = self.mapColumnCount local mapRowCount = self.mapRowCount local mapCellSize = self.mapCellSize local sinTable = self.sinTable local rayY = rayInfo.y local rayX = rayInfo.x local rayYStep = rayInfo.rayYStep local rayXStep = rayInfo.rayXStep local wallFound = false while not wallFound do local mapX = floor(rayX / mapCellSize) local mapY = floor(rayY / mapCellSize) local validX = mapX > 0 and mapX <= mapColumnCount local validY = mapY > 0 and mapY <= mapRowCount local withinMap = validX and validY if not withinMap then rayInfo.distance = MAX_DISTANCE break end local wallId = worldMap[mapX][mapY] wallFound = wallId > 0 if wallFound then local wallInfo = wallDefList[wallId] local isTransparent = wallInfo.isTransparent local distance local offset if isTransparent then local halfYStep = rayYStep * 0.5 local offsetRayY = rayY + halfYStep local yvalue = abs(offsetRayY - ypos) distance = abs(yvalue) / sinTable[rayAngle] local halfStep = rayXStep * 0.5 offset = min(rayX + halfStep, mapCellSize) else local yvalue = abs(rayY - ypos) distance = abs(yvalue / sinTable[rayAngle]); offset = min(rayX, mapCellSize) end rayInfo.wallId = wallId rayInfo.distance = distance rayInfo.offset = offset rayInfo.mapHitX = mapX; rayInfo.mapHitY = mapY; rayInfo.x = rayX; rayInfo.y = rayY; else rayY = rayY + rayYStep rayX = rayX + rayXStep end end return rayInfo end function RaycastEngine:performVerticalCheck(xpos, ypos, rayAngle, worldMap, wallDefList, rayInfo) local mapColumnCount = self.mapColumnCount local mapRowCount = self.mapRowCount local mapCellSize = self.mapCellSize local cosTable = self.cosTable local rayX = rayInfo.x local rayY = rayInfo.y local rayXStep = rayInfo.rayXStep local rayYStep = rayInfo.rayYStep local wallFound = false while not wallFound do local mapX = floor(rayX / mapCellSize) local mapY = floor(rayY / mapCellSize) local validX = mapX > 0 and mapX <= mapColumnCount local validY = mapY > 0 and mapY <= mapRowCount local withinMap = validX and validY if not withinMap then rayInfo.distance = MAX_DISTANCE break end local wallId = worldMap[mapX][mapY] wallFound = wallId > 0 if wallFound then local wallInfo = wallDefList[wallId] local isTransparent = wallInfo.isTransparent local distance local offset if isTransparent then local halfXStep = rayXStep * 0.5 local offsetRayX = rayX + halfXStep local xvalue = abs(offsetRayX - xpos) distance = abs(xvalue) / cosTable[rayAngle] local halfYStep = rayYStep * 0.5 offset = min(newY + halfYStep, mapCellSize) else local xvalue = abs(rayX - xpos) distance = abs(xvalue / cosTable[rayAngle]); offset = min(rayY, mapCellSize) end rayInfo.wallId = wallId rayInfo.distance = distance rayInfo.offset = offset rayInfo.mapHitX = mapX; rayInfo.mapHitY = mapY; rayInfo.x = rayX; rayInfo.y = rayY; else rayY = rayY + rayYStep rayX = rayX + rayXStep end end return rayInfo end function RaycastEngine:processFrame(dt, time, params) local commonAngles = self.commonAngles local heightTable = self.heightTable local cosTable = self.cosTable local wallDefList = params.wallDefList local viewAngle = floor(params.viewAngle) local halfFov = commonAngles[30] local currentAngle = viewAngle - halfFov if currentAngle < commonAngles[0] then currentAngle = currentAngle + commonAngles[360] end local sliceCount = 0 local visibleWidth = params.visibleWidth local maxRayDepth = params.maxRayDepth local xpos = params.xpos local ypos = params.ypos local worldMap = params.worldMap local illegalHorizontalAngles = { [commonAngles[0]] = true, [commonAngles[180]] = true, } local illegalVerticalAngles = { [commonAngles[90]] = true, [commonAngles[270]] = true, } local foundWalls = {} for i = 0, visibleWidth do local solidWallFound = false local hitDepth = 0 local hrayResult = self:getFirstHorizontalIntercept(xpos, ypos, currentAngle) local vrayResult = self:getFirstVerticalIntercept(xpos, ypos, currentAngle) while not solidWallFound and hitDepth < maxRayDepth do local ignoreHorizontalCheck = illegalHorizontalAngles[currentAngle] if not ignoreHorizontalCheck then hrayResult = self:performHorizontalCheck(xpos, ypos, currentAngle, worldMap, wallDefList, hrayResult) end local ignoreVerticalCheck = illegalVerticalAngles[currentAngle] if not ignoreVerticalCheck then vrayResult = self:performVerticalCheck(xpos, ypos, currentAngle, worldMap, wallDefList, vrayResult) end local closestVerticalDistance = vrayResult.distance or MAX_DISTANCE local closestHorizontalDistance = hrayResult.distance or MAX_DISTANCE local useVerticalInfo = closestVerticalDistance < closestHorizontalDistance local result = useVerticalInfo and vrayResult or hrayResult -- fix fisheye local nangle = (commonAngles[330] + i) % commonAngles[360] local cosAngle = cosTable[nangle] local rayDistance = result.distance rayDistance = floor(rayDistance * cosAngle) local sliceHeight = heightTable[rayDistance] -- add wall to render list table.insert(foundWalls, { wallId = result.wallId, offset = result.offset, mapHitX = result.mapHitX, mapHitY = result.mapHitY, distance = rayDistance, sliceHeight = sliceHeight, drawColumn = i, }) result.x = result.x + result.rayXStep result.y = result.y + result.rayYStep local wallTypeInfo = wallDefList[result.wallId] local isSolid = wallTypeInfo.isSolid solidWallFound = isSolid hitDepth = isSolid and hitDepth or (hitDepth + 1) end local nextAngle = currentAngle + 1 local resetAngle = nextAngle > commonAngles[360] currentAngle = resetAngle and (currentAngle - commonAngles[360]) or nextAngle end return foundWalls end function RaycastEngine:updateCameraPosition(params) local commonAngles = self.commonAngles local cameraInfo = params.cameraInfo local worldMap = params.worldMap local movementSpeed = params.movementSpeed local turnSpeed = params.turnSpeed local viewAngle = cameraInfo.viewAngle local xpos = cameraInfo.xpos local ypos = cameraInfo.ypos if movementSpeed ~= 0 then local cosTable = self.cosTable local sinTable = self.sinTable local newX = floor(xpos + (cosTable[viewAngle] * movementSpeed)) local newY = floor(ypos + (sinTable[viewAngle] * movementSpeed)) local clampedX, clampedY = self:clipPlayerMovement { oldX = xpos, oldY = ypos, newX = newX, newY = newY, worldMap = worldMap, } cameraInfo.xpos = clampedX cameraInfo.ypos = clampedY end if turnSpeed ~= 0 then local newViewAngle = floor(viewAngle + turnSpeed) if newViewAngle < commonAngles[0] then newViewAngle = newViewAngle + commonAngles[360] end if newViewAngle > commonAngles[360] then newViewAngle = newViewAngle - commonAngles[360] end cameraInfo.viewAngle = newViewAngle end end function RaycastEngine:clipPlayerMovement(params) local mapCellSize = self.mapCellSize local worldMap = params.worldMap local oldX = params.oldX local oldY = params.oldY local newX = params.newX local newY = params.newY local wallImpact = false local clipDistance = 15 local mapX = floor(newX / mapCellSize) local mapY = floor(newY / mapCellSize) local left = mapX * mapCellSize local top = mapY * mapCellSize local right = left + mapCellSize local bottom = top + mapCellSize local oldX = params.oldX local oldY = params.oldY local newX = params.newX local newY = params.newY local leftMap = mapX - 1 local rightMap = mapX + 1 local topMap = mapY - 1 local bottomMap = mapY + 1 -- movement left if newX < oldX then if worldMap[leftMap][mapY] > 0 then if newX < left or (abs(newX - left) < clipDistance) then newX = oldX wallImpact = true end end end -- movement right if newX > oldX then if worldMap[rightMap][mapY] > 0 then if newX > right or (abs(right - newX) < clipDistance) then newX = oldX wallImpact = true end end end -- movement up if newY < oldY then if worldMap[mapX][topMap] > 0 then if newY < top or (abs(newY - top) < clipDistance) then newY = oldY wallImpact = true end end end -- movement down if newY > oldY then if worldMap[mapX][bottomMap] > 0 then if newY > bottom or (abs(newY - bottom) < clipDistance) then newY = oldY wallImpact = true end end end -- if no wall impact yes, break cell into quads and inspect further if not wallImpact then local halfCellSize = floor(mapCellSize * 0.5) local leftPlusClip = left + clipDistance local topPlusClip = top + clipDistance -- region A if newY < (top + halfCellSize) then if newX < (left + halfCellSize) then if worldMap[leftMap][topMap] > 0 and (newY < topPlusClip) then if newX < leftPlusClip then if oldX > leftPlusClip then newX = oldX else newY = oldY end wallImpact = true end end if worldMap[leftMap][topMap] > 0 and (newX < leftPlusClip) then if newY < topPlusClip then if oldY > topPlusClip then newY = oldY else newX = oldX end wallImpact = true end end end end -- region B if not wallImpact and newX > (right - halfCellSize) then if worldMap[rightMap][topMap] > 0 and newY < topPlusClip then if newX > (right - clipDistance) then if oldX < (right - clipDistance) then newX = oldX else newY = oldY end wallImpact = true end end if worldMap[rightMap][topMap] > 0 and newX > (right - clipDistance) then if newY < topPlusClip then if oldY > topPlusClip then newY = oldY else newX = oldX end wallImpact = true end end end -- region C if not wallImpact and newY > (top + halfCellSize) then if newX < (left + halfCellSize) then if worldMap[leftMap][bottomMap] > 0 and newY > (bottom - halfCellSize) then if newX < (left + clipDistance) then if oldX > (left + clipDistance) then newX = oldX else newY = oldY end end end if worldMap[leftMap][bottomMap] > 0 and newX < (left + clipDistance) then if newY > (bottom - clipDistance) then if oldY < (bottom - clipDistance) then newY = oldY else newX = oldX end wallImpact = true end end end end -- region D if not wallImpact and newX > (right - halfCellSize) then if worldMap[rightMap][bottomMap] > 0 and newY > (bottom - clipDistance) then if newX > (right - clipDistance) then if oldX < (right - clipDistance) then newX = oldX else newY = oldY end wallImpact = true end end if worldMap[rightMap][bottomMap] > 0 and newX > (right - clipDistance) then if newY > (bottom - clipDistance) then if oldY < (bottom - clipDistance) then newY = oldY else newX = oldX end wallImpact = true end end end end return newX, newY end return RaycastEngine |
main.lua
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 | -- Project: Raycasting Engine Demo -- SDK: Corona - 09/12/11 -- Author: Andrew Burch -- Date: 8/02/2012 -- Site: http://www.newhighscore.net -- Contact: andrew.burch@newhighscore.net -- Note: Ported basic aspects from my C++ version of a simple raycasting engine local map = require('map') local input = require('input') local renderer = require('renderer') local raycastengine = require('raycast') -- hide the status bar display.setStatusBar(display.HiddenStatusBar) local contentTop = 0 local contentLeft = 0 local contentWidth = display.contentWidth local contentHeight = display.contentHeight local horizon = contentTop + (contentHeight * 0.5) -- setup background local ceiling = display.newRect(0, 0, contentWidth, horizon) ceiling:setFillColor(20,20,200) local floor = display.newRect(0, horizon, contentWidth, horizon) floor:setFillColor(100,100,100) --initialise camera local mapCellSize = 64 local halfCellSize = mapCellSize * 0.5 local startingColumn = 2 local startingRow = 2 local startX = (startingColumn * mapCellSize) + halfCellSize local startY = (startingRow * mapCellSize) + halfCellSize local cameraInfo = { eyeLevel = halfCellSize, viewAngle = 0, xpos = startX, ypos = startY, mapX = startingColumn, mapY = startingRow, } -- initialise the engine local fov = 60 local maxRayDepth = 2 local engine = raycastengine.new() engine:initialise { visibleWidth = contentWidth, visibleHeight = contentHeight, mapRowCount = map.rowCount, mapColumnCount = map.columnCount, mapCellSize = mapCellSize, fov = fov, maxRayDepth = maxRayDepth, commonAngleList = { 0, 30, 45, 90, 180, 270, 330, 360, }, } -- initialise rendering system local renderingSystem = renderer.new() renderingSystem:initialise { displayWidth = contentWidth, displayHeight = contentHeight, horizon = horizon, columnWidth = 1, } -- initialise input system local inputSystem = input.new() inputSystem:initialise { buttonWidth = 48, buttonHeight = 48, displayWidth = contentWidth, sideBorder = 20, turnAcceleration = 2.0, movementAcceleration = 0.9, } -- movement variables local maxTurnSpeed = 13.5 local maxMovementSpeed = 13.5 local turnDeccelerateFactor = 0.6 local moveDeccelerateFactor = 0.82 local lastUpdateTime = 0 -- register main update listener Runtime:addEventListener("enterFrame", function(event) local time = event.time local dt = (time - lastUpdateTime) / 1000 inputSystem:update(dt, time, { maxTurnSpeed = maxTurnSpeed, maxMovementSpeed = maxMovementSpeed, turnDeccelerateFactor = turnDeccelerateFactor, moveDeccelerateFactor = moveDeccelerateFactor, }) local movementSpeed = inputSystem:getMovementSpeed() local turnSpeed = inputSystem:getTurnSpeed() engine:updateCameraPosition { cameraInfo = cameraInfo, movementSpeed = movementSpeed, turnSpeed = turnSpeed, worldMap = map.mapData, } local sceneInfo = engine:processFrame(dt, time, { xpos = cameraInfo.xpos, ypos = cameraInfo.ypos, viewAngle = cameraInfo.viewAngle, worldMap = map.mapData, wallDefList = map.wallDefList, visibleWidth = contentWidth, maxRayDepth = maxRayDepth, }) renderingSystem:renderScene { sceneInfo = sceneInfo, horizon = horizon, } lastUpdateTime = time end) |
tablex.lua
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | module(..., package.seeall) local insert = table.insert -- removes all entries from a table function clear(table) for k, v in pairs(table) do table[k] = nil end return table end function count(t) local count = 0 for _,v in pairs(t) do count = count + 1 end return count end function icount(t) local i = 0 for _, v in ipairs(t) do i = i + 1 end return i end |
You can also download the code from here
If you have any questions, please contact me. Also feel free to leave comments.
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Replies
Posted on Tue, 2012-02-14 16:06
#2
Thanks for the feedback :)
If you are interested in the theory, you should check this link out: Link
The content here is the same that I learned from all those years ago. Formatting is different so it may have been republished by someone else. I think the axis in my engine is different, but the principles are the same.
I might see if I can republish the information myself, minus all those annoying banners and ads which that link contains.
Posted on Wed, 2012-02-15 04:54
#3
Incredible. Well done and thank you.
Posted on Wed, 2012-02-15 05:26
#4
If I'm not mistaken, having only glanced at the code, you are rendering the polygons using 1-pixel wide, filled rectangles, yes?
If I didn't think someone had already started on this (and if my maths were better) I would write a polygon render function, being that Corona is lacking such a thing.
Posted on Wed, 2012-02-15 08:13
#5
This still amazes me. I read through that link about raycasting (wow that's one LONG document). I'm not a math guy so those parts I was kind of "duhhhhhhh" haha.
The rest was interesting theory. It gives a view how Wolf3d from id software did it. I guess a 2d engine can do 3d under certain circumstance and run pretty damn well too.
A game I used to play years ago was called "Shining in the Darkness" basically the player had a top view of the world, and then dungeons etc. Those dungeons were from a 1st person view, and basically you would hit the up direction on d pad (sega genesis, old school!) and it would go up 1 square.
There was another game called Phantasy Star (the original on Sega Master System, my favorite game of all time!!!) and it did the same type of thing. You had a overworld view, and in towns you had a top down perspective, but in dungeons you had a 1st person view, click up direction and moves 1 square.
What I used to do was buy tons of Graph paper (my favorite paper of all time! hehe) and I would map out he dungeons by hand! I don't know why I was so fascinated with it.
But I think something like this could be used for something like that? But instead of the rigid square by square approach, a dungeon could be made with random encounters and when a player hits the "map" button, it would show an overview of where the player is at. All standard stuff.
In fact, I KNOW it's possible with your code (I can imagine it,so therefore I can be built....or i'm dillusional!). Probably better off doing it in unity3d or something like that, but if someone wanted to kick it old school they could do it this way (I like old school).
What you think?
ng
Posted on Wed, 2012-02-15 14:02
#6
@horacebury: You are correct, I went with flat filled rectangles for the rendering.
A poly render function would be useful for real 3D, but with a raycasting engine, it really is just slices built off a 2D map (2.5D if you will). I could be wrong, but I suspect that calculating and rendering polys would be more processor hungry than changing line/rect heights. Ofcourse, there is the trade off that you have lots of line/rect objects eating up the processor - I'd actually be interested to hear from the guys/girls at Ansca what they think would boost performance.
Some additional thoughts on using the filled rects in this sample:
1) All my graphical samples (found here) were about improving my knowledge on basic graphics with corona. I felt I could easily adjust the resolution by using them with minimal effort.
2) At this point I have not seen a way to plot individual pixels with corona (which would aid texturemapping and also transparent walls). Back in the old days, I'd whip up some assembly and render directly to screen (but those days are gone :()
3) Ideally the walls would be textured, but I could not see any easy way to render a single slice of texture / sprite. I probably should look at doing some sort of sprite demo to get some expeience working with them - Maybe something will crop up that will work.
@ng: You're idea would work and can be done. The raycasting engine (at its core) converts a 2D map position and direction into a 3D view. So jumping in and out would be no problem. In my original engine (written with pascal) I had a map the player could bring up, which was just a textured version of the 2d map (seen in map.lua). The player could walk around with this view and still get all the clipping and open doors, etc. So you could play the game while viewing the 2D map, or in the "3D" view.
The thing with raycasting is it's a tech that was designed back when hardware was way less powerful and using it now is more restrictive than using a true 3D engine. There are tradeoffs no matter which direction you go, but what I always loved about the raycasting engine was how simple it is. The difficulty I see with using it under Corona (right now) is there is no simple way to render a single texture slice from an image or sprite (if someone can point me in the direction of a way, I'll update the raycaster in 5 minutes to render textured walls).
It was also written at a time when I could convert things to assembly to gain even more speed - which I have not been able to do since Gameboy advance days. It's here where using a true 3D engine is more desirable over a raycaster.
Posted on Sun, 2012-02-19 01:58
#7
wow! this is just awesome and I was asking for a sample like this a long time ago.
you, sir, are my personal hero!
-finefin
Posted on Tue, 2012-02-21 06:56
#8
5 stars. :)
Posted on Wed, 2012-02-22 12:04
#9
Wow!
Posted on Thu, 2012-02-23 13:53
#10
Well I guess there is no need for Unity 3D anymore :)
Posted on Mon, 2012-03-26 03:50
#11
Great job, Jesder! How big map can be? And can you explain mapData values?
Posted on Mon, 2012-03-26 18:57
#12
You can make the map much larger - I kept is small since this was purely a demo, and I didn't feel like designing out a large scale map :)
The mapData values are just an index into the wallDefList table. So 0 means it's a blank cell and the player can move there, values 1 onwards are walls.
Posted on Wed, 2012-04-18 23:45
#13
WOW, this example is awesome!!!
it looks like really 3D.
Posted on Sat, 2012-05-26 06:48
#14
Amazing!
Congratulation.....
Ale
Posted on Sun, 2012-07-15 10:31
#15
This demo is VERY SLOW in my ipod touch 4 with ios 5.1.1.
It is working well in your devices?
Do you have any tip for me try to fix it?
Thank you
Posted on Sun, 2012-09-09 12:45
#16
Very futuristic, reminds me of Minecraft. Awesome job!
HOLY CRAAAAAAAAAAAAAAAAAAAAAAAPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
^ That means it's.....amazing. No idea how this works, but I love playing with it.
Wow, just wow.
:)
ng
+1 voted.