raylib/examples/textures_particles_trail_bl...

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Lua

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--
-- raylib example - particles trail blending
--
-- This example has been created using raylib 1.6 (www.raylib.com)
-- raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
--
-- Copyright (c) 2014-2016 Ramon Santamaria (@raysan5)
--
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MAX_PARTICLES = 200
-- Initialization
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local screenWidth = 800
local screenHeight = 450
InitWindow(screenWidth, screenHeight, "raylib [textures] example - particles trail blending")
-- Particles pool, reuse them!
local mouseTail = {}
-- Initialize particles
for i = 1, MAX_PARTICLES do
mouseTail[i] = {}
mouseTail[i].position = Vector2(0, 0)
mouseTail[i].color = Color(GetRandomValue(0, 255), GetRandomValue(0, 255), GetRandomValue(0, 255), 255)
mouseTail[i].alpha = 1.0
mouseTail[i].size = GetRandomValue(1, 30)/20.0
mouseTail[i].rotation = GetRandomValue(0, 360)
mouseTail[i].active = false
end
local gravity = 3.0
local smoke = LoadTexture("resources/smoke.png")
local blending = BlendMode.ALPHA
SetTargetFPS(60)
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-- Main game loop
while not WindowShouldClose() do -- Detect window close button or ESC key
-- Update
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-- Activate one particle every frame and Update active particles
-- NOTE: Particles initial position should be mouse position when activated
-- NOTE: Particles fall down with gravity and rotation... and disappear after 2 seconds (alpha = 0)
-- NOTE: When a particle disappears, active = false and it can be reused.
for i = 1, MAX_PARTICLES do
if (not mouseTail[i].active) then
mouseTail[i].active = true
mouseTail[i].alpha = 1.0
mouseTail[i].position = GetMousePosition()
break
end
end
for i = 1, MAX_PARTICLES do
if (mouseTail[i].active) then
mouseTail[i].position.y = mouseTail[i].position.y + gravity
mouseTail[i].alpha = mouseTail[i].alpha - 0.01
if (mouseTail[i].alpha <= 0.0) then mouseTail[i].active = false end
mouseTail[i].rotation = mouseTail[i].rotation + 5.0
end
end
if (IsKeyPressed(KEY.SPACE)) then
if (blending == BlendMode.ALPHA) then blending = BlendMode.ADDITIVE
else blending = BlendMode.ALPHA end
end
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-- Draw
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BeginDrawing()
ClearBackground(DARKGRAY)
BeginBlendMode(blending)
-- Draw active particles
for i = 1, MAX_PARTICLES do
if (mouseTail[i].active) then
DrawTexturePro(smoke, Rectangle(0, 0, smoke.width, smoke.height),
Rectangle(mouseTail[i].position.x, mouseTail[i].position.y,
smoke.width*mouseTail[i].size//1, smoke.height*mouseTail[i].size//1),
Vector2(smoke.width*mouseTail[i].size/2, smoke.height*mouseTail[i].size/2),
mouseTail[i].rotation, Fade(mouseTail[i].color, mouseTail[i].alpha)) end
end
EndBlendMode()
DrawText("PRESS SPACE to CHANGE BLENDING MODE", 180, 20, 20, BLACK)
if (blending == BlendMode.ALPHA) then DrawText("ALPHA BLENDING", 290, screenHeight - 40, 20, BLACK)
else DrawText("ADDITIVE BLENDING", 280, screenHeight - 40, 20, RAYWHITE) end
EndDrawing()
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end
-- De-Initialization
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UnloadTexture(smoke)
CloseWindow() -- Close window and OpenGL context
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