Merge pull request #468 from Hultan/rlgl_solar_system

Models/rlgl_solar_system example

examples/models/rlgl_solar_system/main.go

@@ -0,0 +1,155 @@
+/*******************************************************************************************
+*
+*   raylib [models] example - rlgl module usage with push/pop matrix transformations
+*
+*   NOTE: This example uses [rlgl] module functionality (pseudo-OpenGL 1.1 style coding)
+*
+*   Example originally created with raylib 2.5, last time updated with raylib 4.0
+*
+*   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) 2018-2024 Ramon Santamaria (@raysan5)
+*
+********************************************************************************************/
+package main
+
+import (
+	"math"
+
+	rl "github.com/gen2brain/raylib-go/raylib"
+)
+
+const (
+	screenWidth  = 800
+	screenHeight = 450
+
+	sunRadius   = 4.0
+	earthRadius = 0.6
+	moonRadius  = 0.16
+
+	earthOrbitRadius = 8.0
+	moonOrbitRadius  = 1.5
+
+	rings, slices = 16, 16
+)
+
+func main() {
+	// Initialization
+	title := "raylib [models] example - rlgl module usage with push/pop matrix transformations"
+	rl.InitWindow(screenWidth, screenHeight, title)
+
+	// Define the camera to look into our 3d world
+	camera := rl.Camera{
+		Position: rl.Vector3{
+			X: 16.0,
+			Y: 16.0,
+			Z: 16.0,
+		}, // Camera position
+		Target:     rl.Vector3{},         // Camera looking at point
+		Up:         rl.Vector3{Y: 1.0},   // Camera up vector (rotation towards target)
+		Fovy:       45.0,                 // Camera field-of-view Y
+		Projection: rl.CameraPerspective, // Camera projection type
+	}
+
+	var rotationSpeed float32 = 0.2 // General system rotation speed
+	var earthRotation float32       // Rotation of earth around itself (days) in degrees
+	var earthOrbitRotation float32  // Rotation of earth around the Sun (years) in degrees
+	var moonRotation float32        // Rotation of moon around itself
+	var moonOrbitRotation float32   // Rotation of moon around earth in degrees
+
+	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.CameraOrbital)
+
+		earthRotation += 5.0 * rotationSpeed
+		earthOrbitRotation += 365 / 360.0 * (5.0 * rotationSpeed) * rotationSpeed
+		moonRotation += 2.0 * rotationSpeed
+		moonOrbitRotation += 8.0 * rotationSpeed
+
+		// Draw
+		rl.BeginDrawing()
+		rl.ClearBackground(rl.RayWhite)
+		rl.BeginMode3D(camera)
+
+		rl.PushMatrix()
+		rl.Scalef(sunRadius, sunRadius, sunRadius) // Scale Sun
+		DrawSphereBasic(rl.Gold)                   // Draw the Sun
+		rl.PopMatrix()
+
+		rl.PushMatrix()
+		rl.Rotatef(earthOrbitRotation, 0.0, 1.0, 0.0) // Rotation for Earth orbit around Sun
+		rl.Translatef(earthOrbitRadius, 0.0, 0.0)     // Translation for Earth orbit
+
+		rl.PushMatrix()
+		rl.Rotatef(earthRotation, 0.25, 1.0, 0.0)        // Rotation for Earth itself
+		rl.Scalef(earthRadius, earthRadius, earthRadius) // Scale Earth
+
+		DrawSphereBasic(rl.Blue) // Draw the Earth
+		rl.PopMatrix()
+
+		rl.Rotatef(moonOrbitRotation, 0.0, 1.0, 0.0)  // Rotation for Moon orbit around Earth
+		rl.Translatef(moonOrbitRadius, 0.0, 0.0)      // Translation for Moon orbit
+		rl.Rotatef(moonRotation, 0.0, 1.0, 0.0)       // Rotation for Moon itself
+		rl.Scalef(moonRadius, moonRadius, moonRadius) // Scale Moon
+
+		DrawSphereBasic(rl.LightGray) // Draw the Moon
+		rl.PopMatrix()
+
+		// Some reference elements (not affected by previous matrix transformations)
+		rl.DrawCircle3D(rl.Vector3{}, earthOrbitRadius, rl.NewVector3(1, 0, 0), 90.0, rl.Fade(rl.Red, 0.5))
+		rl.DrawGrid(20, 1.0)
+
+		rl.EndMode3D()
+
+		rl.DrawText("EARTH ORBITING AROUND THE SUN!", 400, 10, 20, rl.Maroon)
+		rl.DrawFPS(10, 10)
+
+		rl.EndDrawing()
+	}
+
+	// De-Initialization
+	rl.CloseWindow() // Close window and OpenGL context
+}
+
+// DrawSphereBasic draws a sphere without any matrix transformation
+// NOTE: Sphere is drawn in world position ( 0, 0, 0 ) with radius 1.0f
+func DrawSphereBasic(color rl.Color) {
+	// Make sure there is enough space in the internal render batch
+	// buffer to store all required vertex, batch is reset if required
+	rl.CheckRenderBatchLimit((rings + 2) * slices * 6)
+
+	rl.Begin(rl.Triangles)
+	rl.Color4ub(color.R, color.G, color.B, color.A)
+
+	for ring := int32(0); ring < (rings + 2); ring++ {
+		for slice := int32(0); slice < slices; slice++ {
+			rl.Vertex3f(getCoords(ring, slice))
+			rl.Vertex3f(getCoords(ring+1, slice+1))
+			rl.Vertex3f(getCoords(ring+1, slice))
+			rl.Vertex3f(getCoords(ring, slice))
+			rl.Vertex3f(getCoords(ring, slice+1))
+			rl.Vertex3f(getCoords(ring+1, slice+1))
+		}
+	}
+	rl.End()
+}
+
+func getCoords(ring, slice int32) (x, y, z float32) {
+	ringF := float64(ring)
+	sliceF := float64(slice)
+
+	// Calculate angels
+	alpha := rl.Deg2rad * (270 + (180/(float64(rings)+1))*ringF)
+	beta := rl.Deg2rad * (sliceF * 360 / float64(slices))
+
+	// Calculate coords
+	x = float32(math.Cos(alpha) * math.Sin(beta))
+	y = float32(math.Sin(alpha))
+	z = float32(math.Cos(alpha) * math.Cos(beta))
+
+	return x, y, z
+}