123 lines
3 KiB
Go
123 lines
3 KiB
Go
package main
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import (
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"git.terah.dev/UnrealXR/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 rl.Vector2
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Color rl.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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//rl.SetConfigFlags(rl.FlagVsyncHint)
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rl.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 = rl.NewVector2(0, 0)
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mouseTail[i].Color = rl.NewColor(byte(rl.GetRandomValue(0, 255)), byte(rl.GetRandomValue(0, 255)), byte(rl.GetRandomValue(0, 255)), 255)
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mouseTail[i].Alpha = 1.0
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mouseTail[i].Size = float32(rl.GetRandomValue(1, 30)) / 20.0
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mouseTail[i].Rotation = float32(rl.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 := rl.LoadTexture("smoke.png")
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blending := rl.BlendAlpha
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rl.SetTargetFPS(60)
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for !rl.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 = rl.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 rl.IsKeyPressed(rl.KeySpace) {
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if blending == rl.BlendAlpha {
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blending = rl.BlendAdditive
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} else {
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blending = rl.BlendAlpha
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}
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}
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// Draw
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rl.BeginDrawing()
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rl.ClearBackground(rl.DarkGray)
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rl.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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rl.DrawTexturePro(
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smoke,
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rl.NewRectangle(0, 0, float32(smoke.Width), float32(smoke.Height)),
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rl.NewRectangle(mouseTail[i].Position.X, mouseTail[i].Position.Y, float32(smoke.Width)*mouseTail[i].Size, float32(smoke.Height)*mouseTail[i].Size),
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rl.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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rl.Fade(mouseTail[i].Color, mouseTail[i].Alpha),
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)
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}
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}
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rl.EndBlendMode()
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rl.DrawText("PRESS SPACE to CHANGE BLENDING MODE", 180, 20, 20, rl.Black)
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if blending == rl.BlendAlpha {
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rl.DrawText("ALPHA BLENDING", 290, screenHeight-40, 20, rl.Black)
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} else {
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rl.DrawText("ADDITIVE BLENDING", 280, screenHeight-40, 20, rl.RayWhite)
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}
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rl.EndDrawing()
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}
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rl.UnloadTexture(smoke)
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rl.CloseWindow()
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}
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