add core examples

examples/core/scissor_test/main.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	rl "github.com/gen2brain/raylib-go/raylib"
+)
+
+var (
+	screenW = int32(800)
+	screenH = int32(450)
+)
+
+func main() {
+
+	rl.InitWindow(screenW, screenH, "raylib [core] example - scissor test")
+
+	scissorArea := rl.NewRectangle(0, 0, 300, 300)
+	scissorMode := true
+
+	rl.SetTargetFPS(60)
+
+	for !rl.WindowShouldClose() {
+
+		if rl.IsKeyPressed(rl.KeyS) {
+			scissorMode = !scissorMode
+		}
+
+		scissorArea.X = float32(rl.GetMouseX())
+		scissorArea.Y = float32(rl.GetMouseY())
+
+		rl.BeginDrawing()
+
+		rl.ClearBackground(rl.RayWhite)
+
+		if scissorMode {
+			rl.BeginScissorMode(scissorArea.ToInt32().X, scissorArea.ToInt32().Y, scissorArea.ToInt32().Width, scissorArea.ToInt32().Height)
+		}
+
+		rl.DrawRectangle(0, 0, screenW, screenH, rl.Red)
+		rl.DrawText("MOVE MOUSE TO REVEAL TEXT", 190, 200, 20, rl.Black)
+
+		if scissorMode {
+			rl.EndScissorMode()
+		}
+
+		rl.DrawRectangleLinesEx(scissorArea, 1, rl.Black)
+		rl.DrawText("S KEY TO TOGGLE MODE", 10, 10, 20, rl.Black)
+
+		rl.EndDrawing()
+	}
+
+	rl.CloseWindow()
+}