docs(examples): create vertex_displacement example

examples/shaders/vertex_displacement/main.go

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+/*******************************************************************************************
+*
+*   raylib [shaders] example - Vertex displacement
+*
+*   Example complexity rating: [★★★☆] 3/4
+*
+*   Example originally created with raylib 5.0, last time updated with raylib 5.5
+*
+*   Example originally contributed by Alex ZH (@ZzzhHe) and reviewed by Ramon Santamaria (@raysan5)
+*
+*   Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
+*   BSD-like license that allows static linking with closed source software
+*
+*   Copyright (c) 2023-2025 Alex ZH (@ZzzhHe)
+*
+********************************************************************************************/
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	rl "github.com/gen2brain/raylib-go/raylib"
+)
+
+// NOTE: Usage: `PLATFORM_DESKTOP=1 go run .`
+var glslVersion int
+
+func init() {
+	if v, ok := os.LookupEnv("PLATFORM_DESKTOP"); ok && v == "1" {
+		glslVersion = 330
+	} else { // PLATFORM_ANDROID, PLATFORM_WEB
+		glslVersion = 100
+	}
+}
+
+// ------------------------------------------------------------------------------------
+// Program main entry point
+// ------------------------------------------------------------------------------------
+func main() {
+	// Initialization
+	//--------------------------------------------------------------------------------------
+	const screenWidth int32 = 800
+	const screenHeight int32 = 450
+
+	rl.SetConfigFlags(rl.FlagMsaa4xHint) // Enable Multi Sampling Anti Aliasing 4x (if available)
+
+	rl.InitWindow(screenWidth, screenHeight, "raylib [shaders] example - vertex displacement")
+	defer rl.CloseWindow() // Close window and OpenGL context
+
+	// Set up camera
+	camera := rl.Camera{
+		Position:   rl.NewVector3(20.0, 5.0, -20.0),
+		Target:     rl.Vector3Zero(),
+		Up:         rl.NewVector3(0.0, 1.0, 0.0),
+		Fovy:       60.0,
+		Projection: rl.CameraPerspective,
+	}
+
+	// Load vertex and fragment shaders
+	shaderDir := fmt.Sprintf("glsl%d", glslVersion)
+
+	shader := rl.LoadShader(
+		filepath.Join(shaderDir, "vertex_displacement.vs"),
+		filepath.Join(shaderDir, "vertex_displacement.fs"),
+	)
+	defer rl.UnloadShader(shader)
+
+	timeLoc := rl.GetShaderLocation(shader, "time")
+
+	// Load perlin noise texture
+	perlinNoiseImage := rl.GenImagePerlinNoise(512, 512, 0, 0, 1.0)
+	perlinNoiseMap := rl.LoadTextureFromImage(perlinNoiseImage)
+	defer rl.UnloadTexture(perlinNoiseMap)
+	rl.UnloadImage(perlinNoiseImage)
+
+	// Set shader uniform location
+	perlinNoiseMapLoc := rl.GetShaderLocation(shader, "perlinNoiseMap")
+	rl.EnableShader(shader.ID)
+	rl.ActiveTextureSlot(1)
+	rl.EnableTexture(perlinNoiseMap.ID)
+	rl.SetUniformSampler(perlinNoiseMapLoc, 1)
+
+	// Create a plane mesh and model
+	planeMesh := rl.GenMeshPlane(50, 50, 50, 50)
+	planeModel := rl.LoadModelFromMesh(planeMesh)
+	defer rl.UnloadModel(planeModel)
+
+	// Set plane model material
+	planeModel.Materials.Shader = shader
+
+	timer := float32(0)
+
+	rl.DisableCursor()
+
+	rl.SetTargetFPS(60) // Set our game to run at 60 frames-per-second
+	//--------------------------------------------------------------------------------------
+
+	// Main game loop
+	for !rl.WindowShouldClose() { // Detect window close button or ESC key
+		// Update
+		//----------------------------------------------------------------------------------
+		rl.UpdateCamera(&camera, rl.CameraFree) // Update camera with free camera mode
+
+		deltaTime := rl.GetFrameTime()
+		timer += deltaTime
+		timeValue := []float32{timer}
+
+		rl.SetShaderValue(shader, timeLoc, timeValue, rl.ShaderUniformFloat) // Send time value to shader
+		//----------------------------------------------------------------------------------
+
+		// Draw
+		//----------------------------------------------------------------------------------
+		rl.BeginDrawing()
+
+		rl.ClearBackground(rl.RayWhite)
+
+		rl.BeginMode3D(camera)
+
+		rl.BeginShaderMode(shader)
+
+		// Draw plane model
+		rl.DrawModel(planeModel, rl.Vector3Zero(), 1.0, rl.White)
+
+		rl.EndShaderMode()
+
+		rl.EndMode3D()
+
+		rl.DrawText("Vertex displacement", 10, 10, 20, rl.DarkGray)
+
+		rl.DrawFPS(10, 40)
+
+		rl.EndDrawing()
+		//----------------------------------------------------------------------------------
+	}
+
+	// De-Initialization
+	//--------------------------------------------------------------------------------------
+	// NOTE: Unload all loaded resources at this point (that are not `defer`-ed)
+	//--------------------------------------------------------------------------------------
+}