225 lines
6.9 KiB
Lua
225 lines
6.9 KiB
Lua
-- Defines
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local RESOLUTION = { 128, 128 }
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local TILE_SIZE = 8
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local LEVEL_SIZE = RESOLUTION[1] / TILE_SIZE
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local STATE = { TITLE = 0, GAME = 1, OVER = 2 } -- Enum wannabe.
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-- Resources
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local framebuffer = -1
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local monitor = 0
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local monitorPos = RL_GetMonitorPosition( monitor )
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local monitorSize = RL_GetMonitorSize( monitor )
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local winScale = 6
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local winSize = { RESOLUTION[1] * winScale, RESOLUTION[2] * winScale }
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local gameState = STATE.GAME
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local grassTexture = -1
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local snakeTexture = -1
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local appleTexture = -1
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local gameSpeed = 7.0
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local moveTimer = 1.0
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local snake = {}
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local applePos = {}
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local function setSnake()
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snake = {
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heading = { 1, 0 },
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control = { 1, 0 },
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headPos = { LEVEL_SIZE / 2, LEVEL_SIZE / 2 },
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segments = {},
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grow = 2,
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}
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end
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local function vector2IsEqual( v1, v2 )
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return v1[1] == v2[1] and v1[2] == v2[2]
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end
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local function addSegment()
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-- If first segment, grow from head and otherwise from tail. New segments are inserted firts.
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if #snake.segments == 0 then
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table.insert( snake.segments, 1, { pos = snake.headPos, heading = snake.heading } )
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else
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table.insert( snake.segments, 1, { pos = snake.segments[ #snake.segments ].pos,
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heading = snake.segments[ #snake.segments ].heading } )
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end
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end
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local function setApplePos()
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applePos = { math.random( 0, LEVEL_SIZE - 1 ), math.random( 0, LEVEL_SIZE - 1 ) }
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local search = true
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while search do
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search = false
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applePos = { math.random( 0, LEVEL_SIZE - 1 ), math.random( 0, LEVEL_SIZE - 1 ) }
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for _, seg in ipairs( snake.segments ) do
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search = vector2IsEqual( applePos, seg.pos )
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if search then
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break
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end
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end
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end
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end
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-- Init.
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function init()
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RL_SetWindowState( FLAG_WINDOW_RESIZABLE )
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RL_SetWindowSize( winSize )
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RL_SetWindowPosition( { monitorPos[1] + monitorSize[1] / 2 - winSize[1] / 2, monitorPos[2] + monitorSize[2] / 2 - winSize[2] / 2 } )
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RL_SetWindowTitle( "Snake" )
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RL_SetWindowIcon( RL_LoadImage( RL_GetBasePath().."../resources/images/apple.png" ) )
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framebuffer = RL_LoadRenderTexture( RESOLUTION )
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grassTexture = RL_LoadTexture( RL_GetBasePath().."../resources/images/grass.png" )
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snakeTexture = RL_LoadTexture( RL_GetBasePath().."../resources/images/snake.png" )
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appleTexture = RL_LoadTexture( RL_GetBasePath().."../resources/images/apple.png" )
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setSnake()
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setApplePos()
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end
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-- Process.
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local function moveSnake()
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-- Check if snake has eaten and should grow.
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if 0 < snake.grow then
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addSegment()
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snake.grow = snake.grow - 1
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end
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-- Move body.
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for i, seg in ipairs( snake.segments ) do
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if i < #snake.segments then
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seg.pos = snake.segments[ i+1 ].pos
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seg.heading = snake.segments[ i+1 ].heading
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else
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seg.pos = snake.headPos
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seg.heading = snake.heading
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end
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end
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-- Move head.
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snake.heading = { snake.control[1], snake.control[2] }
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snake.headPos = { snake.headPos[1] + snake.heading[1], snake.headPos[2] + snake.heading[2] }
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-- Check appple eating.
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if vector2IsEqual( snake.headPos, applePos ) then
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snake.grow = snake.grow + 1
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setApplePos()
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end
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-- Check if hit to body.
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for _, seg in ipairs( snake.segments ) do
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if vector2IsEqual( snake.headPos, seg.pos ) then
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gameState = STATE.OVER
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end
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end
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-- Check if outside or level.
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if snake.headPos[1] < 0 or LEVEL_SIZE <= snake.headPos[1] or snake.headPos[2] < 0 or LEVEL_SIZE <= snake.headPos[2] then
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gameState = STATE.OVER
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end
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moveTimer = moveTimer + 1.0
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end
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function process( delta )
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if gameState == STATE.GAME then -- Run game.
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-- Controls.
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if RL_IsKeyPressed( KEY_RIGHT ) and 0 <= snake.heading[1] then
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snake.control = { 1, 0 }
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elseif RL_IsKeyPressed( KEY_LEFT ) and snake.heading[1] <= 0 then
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snake.control = { -1, 0 }
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elseif RL_IsKeyPressed( KEY_DOWN ) and 0 <= snake.heading[2] then
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snake.control = { 0, 1 }
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elseif RL_IsKeyPressed( KEY_UP ) and snake.heading[2] <= 0 then
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snake.control = { 0, -1 }
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end
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moveTimer = moveTimer - gameSpeed * delta
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if moveTimer <= 0.0 then
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moveSnake()
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end
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elseif gameState == STATE.OVER and RL_IsKeyPressed( KEY_ENTER ) then -- Reset game.
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setSnake()
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setApplePos()
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gameState = STATE.GAME
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end
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end
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-- Drawing.
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local function drawGrass()
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for y = 0, LEVEL_SIZE - 1 do
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for x = 0, LEVEL_SIZE - 1 do
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RL_DrawTexture( grassTexture, { x * TILE_SIZE, y * TILE_SIZE }, WHITE )
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end
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end
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end
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--[[ Check if next segment is on left side. There are more mathematically elegant solution to this, but there is
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only four possibilities so we can just check them all. ]]--
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local function onLeft( this, next )
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return ( vector2IsEqual( this, { 0, -1 } ) and vector2IsEqual( next, { -1, 0 } ) )
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or ( vector2IsEqual( this, { -1, 0 } ) and vector2IsEqual( next, { 0, 1 } ) )
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or ( vector2IsEqual( this, { 0, 1 } ) and vector2IsEqual( next, { 1, 0 } ) )
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or ( vector2IsEqual( this, { 1, 0 } ) and vector2IsEqual( next, { 0, -1 } ) )
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end
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local function drawSnake()
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for i, seg in ipairs( snake.segments ) do
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local angle = math.deg( RL_Vector2Angle( { 0, 0 }, seg.heading ) )
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local source = { 16, 0, 8, 8 }
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if i == 1 then -- Tail segment. Yes tail is actually the 'first' segment.
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source[1] = 8
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if 1 < #snake.segments then
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angle = math.deg( RL_Vector2Angle( { 0, 0 }, snake.segments[ 2 ].heading ) )
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end
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elseif i < #snake.segments and not vector2IsEqual( seg.heading, snake.segments[ i+1 ].heading ) then -- Turned middle segments.
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source[1] = 0
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-- Mirror turned segment to other way.
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if onLeft( seg.heading, snake.segments[ i+1 ].heading ) then
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source[4] = -8
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end
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elseif i == #snake.segments and not vector2IsEqual( seg.heading, snake.heading ) then -- Turned segment before head.
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source[1] = 0
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if onLeft( seg.heading, snake.heading ) then
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source[4] = -8
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end
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end
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-- Notice that we set the origin to center { 4, 4 } that acts as pivot point. We also have to adjust our dest position by 4.
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RL_DrawTexturePro( snakeTexture, source, { seg.pos[1] * TILE_SIZE + 4, seg.pos[2] * TILE_SIZE + 4, 8, 8 }, { 4, 4 }, angle, WHITE )
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end
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-- Let's draw the head last to keep it on top.
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local angle = math.deg( RL_Vector2Angle( { 0, 0 }, snake.heading ) )
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RL_DrawTexturePro( snakeTexture, { 24, 0, 8, 8 }, { snake.headPos[1] * TILE_SIZE + 4, snake.headPos[2] * TILE_SIZE + 4, 8, 8 }, { 4, 4 }, angle, WHITE )
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end
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local function drawApple()
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RL_DrawTexture( appleTexture, { applePos[1] * TILE_SIZE, applePos[2] * TILE_SIZE }, WHITE )
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end
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function draw()
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-- Clear the window to black.
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RL_ClearBackground( BLACK )
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-- Draw to framebuffer.
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RL_BeginTextureMode( framebuffer )
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RL_ClearBackground( BLACK )
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drawGrass()
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drawSnake()
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drawApple()
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if gameState == STATE.OVER then
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RL_DrawText( 0, "Press Enter to\nrestart", { 10, 10 }, 10, 2, WHITE )
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end
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RL_EndTextureMode()
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-- Draw framebuffer to window.
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RL_SetTextureSource( TEXTURE_SOURCE_RENDER_TEXTURE )
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RL_DrawTexturePro( framebuffer, { 0, 0, RESOLUTION[1], -RESOLUTION[2] }, { 0, 0, winSize[1], winSize[2] }, { 0, 0 }, 0.0, WHITE )
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RL_SetTextureSource( TEXTURE_SOURCE_TEXTURE )
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end
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