Update C sources and examples

examples/textures/particles_blending/main.go

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