123 lines
3.1 KiB
Go
123 lines
3.1 KiB
Go
package main
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import (
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"github.com/gen2brain/raylib-go/raylib"
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)
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const (
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maxParticles = 200
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)
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type particle struct {
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Position raylib.Vector2
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Color raylib.Color
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Alpha float32
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Size float32
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Rotation float32
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Active bool
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}
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func main() {
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screenWidth := int32(800)
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screenHeight := int32(450)
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//raylib.SetConfigFlags(raylib.FlagVsyncHint)
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raylib.InitWindow(screenWidth, screenHeight, "raylib [textures] example - particles blending")
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// Particles pool, reuse them!
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mouseTail := make([]particle, maxParticles)
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// Initialize particles
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for i := 0; i < maxParticles; i++ {
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mouseTail[i].Position = raylib.NewVector2(0, 0)
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mouseTail[i].Color = raylib.NewColor(byte(raylib.GetRandomValue(0, 255)), byte(raylib.GetRandomValue(0, 255)), byte(raylib.GetRandomValue(0, 255)), 255)
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mouseTail[i].Alpha = 1.0
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mouseTail[i].Size = float32(raylib.GetRandomValue(1, 30)) / 20.0
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mouseTail[i].Rotation = float32(raylib.GetRandomValue(0, 360))
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mouseTail[i].Active = false
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}
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gravity := float32(3.0)
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smoke := raylib.LoadTexture("smoke.png")
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blending := raylib.BlendAlpha
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raylib.SetTargetFPS(60)
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for !raylib.WindowShouldClose() {
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// Update
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// Activate one particle every frame and Update active particles
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// NOTE: Particles initial position should be mouse position when activated
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// NOTE: Particles fall down with gravity and rotation... and disappear after 2 seconds (alpha = 0)
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// NOTE: When a particle disappears, active = false and it can be reused.
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for i := 0; i < maxParticles; i++ {
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if !mouseTail[i].Active {
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mouseTail[i].Active = true
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mouseTail[i].Alpha = 1.0
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mouseTail[i].Position = raylib.GetMousePosition()
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i = maxParticles
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}
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}
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for i := 0; i < maxParticles; i++ {
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if mouseTail[i].Active {
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mouseTail[i].Position.Y += gravity
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mouseTail[i].Alpha -= 0.01
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if mouseTail[i].Alpha <= 0.0 {
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mouseTail[i].Active = false
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}
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mouseTail[i].Rotation += 5.0
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}
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}
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if raylib.IsKeyPressed(raylib.KeySpace) {
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if blending == raylib.BlendAlpha {
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blending = raylib.BlendAdditive
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} else {
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blending = raylib.BlendAlpha
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}
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}
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// Draw
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raylib.BeginDrawing()
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raylib.ClearBackground(raylib.DarkGray)
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raylib.BeginBlendMode(blending)
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// Draw active particles
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for i := 0; i < maxParticles; i++ {
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if mouseTail[i].Active {
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raylib.DrawTexturePro(
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smoke,
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raylib.NewRectangle(0, 0, smoke.Width, smoke.Height),
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raylib.NewRectangle(int32(mouseTail[i].Position.X), int32(mouseTail[i].Position.Y), smoke.Width*int32(mouseTail[i].Size), smoke.Height*int32(mouseTail[i].Size)),
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raylib.NewVector2(float32(smoke.Width)*mouseTail[i].Size/2, float32(smoke.Height)*mouseTail[i].Size/2),
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mouseTail[i].Rotation,
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raylib.Fade(mouseTail[i].Color, mouseTail[i].Alpha),
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)
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}
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}
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raylib.EndBlendMode()
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raylib.DrawText("PRESS SPACE to CHANGE BLENDING MODE", 180, 20, 20, raylib.Black)
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if blending == raylib.BlendAlpha {
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raylib.DrawText("ALPHA BLENDING", 290, screenHeight-40, 20, raylib.Black)
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} else {
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raylib.DrawText("ADDITIVE BLENDING", 280, screenHeight-40, 20, raylib.RayWhite)
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}
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raylib.EndDrawing()
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}
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raylib.UnloadTexture(smoke)
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raylib.CloseWindow()
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}
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