Added [models] example - skybox loading and drawing

examples/models/skybox/main.go

@@ -0,0 +1,125 @@
+package main
+
+import (
+	"fmt"
+	"path/filepath"
+	"unsafe"
+
+	rl "github.com/gen2brain/raylib-go/raylib"
+)
+
+func main() {
+	skyboxFilename := "skybox.png"
+
+	rl.InitWindow(800, 450, "raylib [models] example - skybox loading and drawing")
+
+	camera := rl.NewCamera3D(
+		rl.NewVector3(1.0, 1.0, 1.0),
+		rl.NewVector3(4.0, 1.0, 4.0),
+		rl.NewVector3(0.0, 1.0, 0.0),
+		45.0,
+		rl.CameraPerspective,
+	)
+
+	// load skybox shader and set required locations
+	skyboxShader := rl.LoadShader("skybox.vs", "skybox.fs")
+
+	setShaderIntValue(skyboxShader, "environmentMap", rl.MapCubemap)
+
+	// load skybox model
+	cube := rl.GenMeshCube(1.0, 1.0, 1.0)
+	skybox := rl.LoadModelFromMesh(cube)
+
+	skybox.Materials.Shader = skyboxShader
+
+	// load cubemap texture
+	skyboxImg := rl.LoadImage(skyboxFilename)
+
+	skyboxTexture := rl.LoadTextureCubemap(skyboxImg, rl.CubemapLayoutAutoDetect)
+
+	rl.UnloadImage(skyboxImg)
+
+	rl.SetMaterialTexture(skybox.Materials, rl.MapCubemap, skyboxTexture)
+
+	// limit cursor to relative movement inside the window
+	rl.DisableCursor()
+
+	// set our game to run at 60 frames-per-second
+	rl.SetTargetFPS(60)
+
+	for !rl.WindowShouldClose() {
+		rl.UpdateCamera(&camera, rl.CameraFirstPerson)
+
+		// load new cubemap texture on drag&drop
+		if rl.IsFileDropped() {
+			droppedFiles := rl.LoadDroppedFiles()
+
+			// only support one file dropped
+			if len(droppedFiles) == 1 {
+				switch filepath.Ext(droppedFiles[0]) {
+				case ".png", ".jpg", ".bmp", ".tga":
+					skyboxFilename = droppedFiles[0]
+
+					rl.UnloadTexture(skyboxTexture)
+
+					img := rl.LoadImage(skyboxFilename)
+
+					skyboxTexture = rl.LoadTextureCubemap(img, rl.CubemapLayoutAutoDetect)
+
+					rl.UnloadImage(img)
+
+					rl.SetMaterialTexture(skybox.Materials, rl.MapCubemap, skyboxTexture)
+				}
+			}
+
+			rl.UnloadDroppedFiles()
+		}
+
+		rl.BeginDrawing()
+
+		rl.ClearBackground(rl.White)
+
+		rl.BeginMode3D(camera)
+
+		// we are inside the cube, we need to disable backface culling
+		rl.DisableBackfaceCulling()
+		rl.DisableDepthMask()
+
+		rl.DrawModel(skybox, rl.NewVector3(0, 0, 0), 1.0, rl.White)
+
+		// restore depth and backface culling
+		rl.EnableBackfaceCulling()
+		rl.EnableDepthMask()
+
+		rl.DrawGrid(10, 1.0)
+
+		rl.EndMode3D()
+
+		rl.DrawText(
+			fmt.Sprintf("File: %s", skyboxFilename),
+			10,
+			int32(rl.GetScreenHeight()-20),
+			10,
+			rl.Black,
+		)
+
+		rl.DrawFPS(10, 10)
+
+		rl.EndDrawing()
+	}
+
+	rl.UnloadModel(skybox)
+	rl.UnloadTexture(skyboxTexture)
+	rl.UnloadShader(skyboxShader)
+
+	rl.CloseWindow()
+}
+
+func setShaderIntValue(shader rl.Shader, name string, value int32) {
+	rl.SetShaderValue(
+		shader,
+		rl.GetShaderLocation(shader, name),
+		unsafe.Slice((*float32)(unsafe.Pointer(&value)), 4),
+		rl.ShaderUniformInt,
+	)
+}