add more Core examples

examples/core/smooth_pixelperfect/main.go

@@ -0,0 +1,85 @@
+package main
+
+import (
+	"fmt"
+	"math"
+
+	rl "github.com/gen2brain/raylib-go/raylib"
+)
+
+const screenW = int32(1280)
+const screenH = int32(720)
+const virtualScreenW = screenW / 5
+const virtualScreenH = screenH / 5
+const virtualRatio = float32(screenW) / float32(virtualScreenW)
+
+func main() {
+
+	rl.InitWindow(screenW, screenH, "raylib [core] example - smooth pixel-perfect camera")
+
+	worldSpaceCam := rl.Camera2D{}
+	worldSpaceCam.Zoom = 1
+
+	screenSpaceCam := rl.Camera2D{}
+	screenSpaceCam.Zoom = 1
+
+	target := rl.LoadRenderTexture(virtualScreenW, virtualScreenH)
+
+	rec1 := rl.NewRectangle(120, 60, 80, 40)
+	rec2 := rl.NewRectangle(130, 70, 90, 30)
+	rec3 := rl.NewRectangle(140, 80, 65, 45)
+
+	sourceRec := rl.NewRectangle(0, 0, float32(target.Texture.Width), -float32(target.Texture.Height))
+	destRec := rl.NewRectangle(-virtualRatio, -virtualRatio, float32(screenW)+(virtualRatio*2), float32(screenH)+(virtualRatio*2))
+
+	origin := rl.NewVector2(0, 0)
+
+	rotation, camX, camY := float32(0), float32(0), float32(0)
+
+	rl.SetTargetFPS(60)
+
+	for !rl.WindowShouldClose() {
+
+		rotation += 60 * rl.GetFrameTime()
+
+		camX = float32(math.Sin(rl.GetTime()) * 50)
+		camY = float32(math.Cos(rl.GetTime()) * 30)
+
+		screenSpaceCam.Target = rl.NewVector2(camX, camY)
+
+		worldSpaceCam.Target.X = screenSpaceCam.Target.X
+		screenSpaceCam.Target.X -= worldSpaceCam.Target.X
+		screenSpaceCam.Target.X *= virtualRatio
+
+		worldSpaceCam.Target.Y = screenSpaceCam.Target.Y
+		screenSpaceCam.Target.Y -= worldSpaceCam.Target.Y
+		screenSpaceCam.Target.Y *= virtualRatio
+
+		rl.BeginTextureMode(target)
+		rl.ClearBackground(rl.RayWhite)
+		rl.BeginMode2D(worldSpaceCam)
+
+		rl.DrawRectanglePro(rec1, origin, rotation, rl.Black)
+		rl.DrawRectanglePro(rec2, origin, -rotation, rl.Red)
+		rl.DrawRectanglePro(rec3, origin, rotation+45, rl.Blue)
+
+		rl.EndMode2D()
+		rl.EndTextureMode()
+
+		rl.BeginDrawing()
+		rl.ClearBackground(rl.Red)
+		rl.BeginMode2D(screenSpaceCam)
+		rl.DrawTexturePro(target.Texture, sourceRec, destRec, origin, 0, rl.White)
+		rl.EndMode2D()
+
+		rl.DrawText("screen res "+fmt.Sprint(screenW)+"x"+fmt.Sprint(screenH), 10, 10, 20, rl.Black)
+		rl.DrawText("world res "+fmt.Sprint(virtualScreenW)+"x"+fmt.Sprint(virtualScreenH), 10, 30, 20, rl.Black)
+		rl.DrawFPS(screenW-100, 10)
+
+		rl.EndDrawing()
+	}
+
+	rl.UnloadRenderTexture(target)
+
+	rl.CloseWindow()
+}