Reimplement camera in Go

raylib/rcamera.go

@@ -1,21 +1,350 @@
-//go:build !android
-// +build !android
-
 package rl
 
-/*
-#include "raylib.h"
-*/
-import "C"
+// GetCameraForward - Returns the cameras forward vector (normalized)
+func GetCameraForward(camera *Camera) Vector3 {
+	return Vector3Normalize(Vector3Subtract(camera.Target, camera.Position))
+}
+
+// GetCameraUp - Returns the cameras up vector (normalized)
+// Note: The up vector might not be perpendicular to the forward vector
+func GetCameraUp(camera *Camera) Vector3 {
+	return Vector3Normalize(camera.Up)
+}
+
+// GetCameraRight - Returns the cameras right vector (normalized)
+func GetCameraRight(camera *Camera) Vector3 {
+	forward := GetCameraForward(camera)
+	up := GetCameraUp(camera)
+
+	return Vector3CrossProduct(forward, up)
+}
+
+// CameraMoveForward - Moves the camera in its forward direction
+func CameraMoveForward(camera *Camera, distance float32, moveInWorldPlane uint8) {
+	forward := GetCameraForward(camera)
+
+	if moveInWorldPlane != 0 {
+		// Project vector onto world plane
+		forward.Y = float32(0)
+		forward = Vector3Normalize(forward)
+	}
+
+	// Scale by distance
+	forward = Vector3Scale(forward, distance)
+
+	// Move position and target
+	camera.Position = Vector3Add(camera.Position, forward)
+	camera.Target = Vector3Add(camera.Target, forward)
+}
+
+// CameraMoveUp - Moves the camera in its up direction
+func CameraMoveUp(camera *Camera, distance float32) {
+	up := GetCameraUp(camera)
+
+	// Scale by distance
+	up = Vector3Scale(up, distance)
+
+	// Move position and target
+	camera.Position = Vector3Add(camera.Position, up)
+	camera.Target = Vector3Add(camera.Target, up)
+}
+
+// CameraMoveRight - Moves the camera target in its current right direction
+func CameraMoveRight(camera *Camera, distance float32, moveInWorldPlane uint8) {
+	right := GetCameraRight(camera)
+
+	if moveInWorldPlane != 0 {
+		// Project vector onto world plane
+		right.Y = float32(0)
+		right = Vector3Normalize(right)
+	}
+
+	// Scale by distance
+	right = Vector3Scale(right, distance)
+
+	// Move position and target
+	camera.Position = Vector3Add(camera.Position, right)
+	camera.Target = Vector3Add(camera.Target, right)
+}
+
+// CameraMoveToTarget - Moves the camera position closer/farther to/from the camera target
+func CameraMoveToTarget(camera *Camera, delta float32) {
+	distance := Vector3Distance(camera.Position, camera.Target)
+
+	// Apply delta
+	distance = distance + delta
+
+	// Distance must be greater than 0
+	if distance <= float32(0) {
+		distance = 0.001
+	}
+
+	// Set new distance by moving the position along the forward vector
+	forward := GetCameraForward(camera)
+	camera.Position = Vector3Add(camera.Target, Vector3Scale(forward, -distance))
+}
+
+// CameraYaw - Rotates the camera around its up vector
+// Yaw is "looking left and right"
+// If rotateAroundTarget is false, the camera rotates around its position
+// Note: angle must be provided in radians
+func CameraYaw(camera *Camera, angle float32, rotateAroundTarget uint8) {
+	// Rotation axis
+	var up = GetCameraUp(camera)
+
+	// View vector
+	var targetPosition = Vector3Subtract(camera.Target, camera.Position)
+
+	// Rotate view vector around up axis
+	targetPosition = Vector3RotateByAxisAngle(targetPosition, up, angle)
+
+	if rotateAroundTarget != 0 {
+		// Move position relative to target
+		camera.Position = Vector3Subtract(camera.Target, targetPosition)
+	} else {
+		// Move target relative to position
+		camera.Target = Vector3Add(camera.Position, targetPosition)
+	}
+}
+
+// CameraPitch - Rotates the camera around its right vector, pitch is "looking up and down"
+//   - lockView prevents camera overrotation (aka "somersaults")
+//   - rotateAroundTarget defines if rotation is around target or around its position
+//   - rotateUp rotates the up direction as well (typically only usefull in CAMERA_FREE)
+//
+// NOTE: angle must be provided in radians
+func CameraPitch(camera *Camera, angle float32, lockView uint8, rotateAroundTarget uint8, rotateUp uint8) {
+	// Up direction
+	var up = GetCameraUp(camera)
+
+	// View vector
+	var targetPosition = Vector3Subtract(camera.Target, camera.Position)
+
+	if lockView != 0 {
+		// In these camera modes we clamp the Pitch angle
+		// to allow only viewing straight up or down.
+
+		// Clamp view up
+		var maxAngleUp float32 = Vector3Angle(up, targetPosition)
+		maxAngleUp = maxAngleUp - 0.001 // avoid numerical errors
+		if angle > maxAngleUp {
+			angle = maxAngleUp
+		}
+
+		// Clamp view down
+		var maxAngleDown float32 = Vector3Angle(Vector3Negate(up), targetPosition)
+		maxAngleDown = maxAngleDown * -1.0  // downwards angle is negative
+		maxAngleDown = maxAngleDown + 0.001 // avoid numerical errors
+		if angle < maxAngleDown {
+			angle = maxAngleDown
+		}
+	}
+
+	// Rotation axis
+	var right = GetCameraRight(camera)
+
+	// Rotate view vector around right axis
+	targetPosition = Vector3RotateByAxisAngle(targetPosition, right, angle)
+
+	if rotateAroundTarget != 0 {
+		// Move position relative to target
+		camera.Position = Vector3Subtract(camera.Target, targetPosition)
+	} else {
+		// Move target relative to position
+		camera.Target = Vector3Add(camera.Position, targetPosition)
+	}
+
+	if rotateUp != 0 {
+		// Rotate up direction around right axis
+		camera.Up = Vector3RotateByAxisAngle(camera.Up, right, angle)
+	}
+}
+
+// CameraRoll - Rotates the camera around its forward vector
+// Roll is "turning your head sideways to the left or right"
+// Note: angle must be provided in radians
+func CameraRoll(camera *Camera, angle float32) {
+	// Rotation axis
+	var forward = GetCameraForward(camera)
+
+	// Rotate up direction around forward axis
+	camera.Up = Vector3RotateByAxisAngle(camera.Up, forward, angle)
+}
+
+// GetCameraViewMatrix - Returns the camera view matrix
+func GetCameraViewMatrix(camera *Camera) Matrix {
+	return MatrixLookAt(camera.Position, camera.Target, camera.Up)
+}
+
+// GetCameraProjectionMatrix - Returns the camera projection matrix
+func GetCameraProjectionMatrix(camera *Camera, aspect float32) Matrix {
+	if camera.Projection == CameraPerspective {
+		return MatrixPerspective(camera.Fovy*(Pi/180.0), aspect, 0.01, 1000.0)
+	} else if camera.Projection == CameraOrthographic {
+		top := camera.Fovy / 2.0
+		right := top * aspect
+
+		return MatrixOrtho(-right, right, -top, top, 0.01, 1000.0)
+	}
+
+	return MatrixIdentity()
+}
 
 // UpdateCamera - Update camera position for selected mode
+// Camera mode: CameraFree, CameraFirstPerson, CameraThirdPerson, CameraOrbital or Custom
 func UpdateCamera(camera *Camera, mode CameraMode) {
-	ccamera := camera.cptr()
-	C.UpdateCamera(ccamera, C.int(mode))
+	var mousePositionDelta = GetMouseDelta()
+
+	moveInWorldPlaneBool := mode == CameraFirstPerson || mode == CameraThirdPerson
+	var moveInWorldPlane uint8
+	if moveInWorldPlaneBool {
+		moveInWorldPlane = 1
+	}
+
+	rotateAroundTargetBool := mode == CameraThirdPerson || mode == CameraOrbital
+	var rotateAroundTarget uint8
+	if rotateAroundTargetBool {
+		rotateAroundTarget = 1
+	}
+
+	lockViewBool := mode == CameraFirstPerson || mode == CameraThirdPerson || mode == CameraOrbital
+	var lockView uint8
+	if lockViewBool {
+		lockView = 1
+	}
+
+	var rotateUp uint8
+
+	if mode == CameraOrbital {
+		// Orbital can just orbit
+		var rotation = MatrixRotate(GetCameraUp(camera), 0.5*GetFrameTime())
+		var view = Vector3Subtract(camera.Position, camera.Target)
+		view = Vector3Transform(view, rotation)
+		camera.Position = Vector3Add(camera.Target, view)
+	} else {
+		// Camera rotation
+		if IsKeyDown(KeyDown) {
+			CameraPitch(camera, -0.03, lockView, rotateAroundTarget, rotateUp)
+		}
+		if IsKeyDown(KeyUp) {
+			CameraPitch(camera, 0.03, lockView, rotateAroundTarget, rotateUp)
+		}
+		if IsKeyDown(KeyRight) {
+			CameraYaw(camera, -0.03, rotateAroundTarget)
+		}
+		if IsKeyDown(KeyLeft) {
+			CameraYaw(camera, 0.03, rotateAroundTarget)
+		}
+		if IsKeyDown(KeyQ) {
+			CameraRoll(camera, -0.03)
+		}
+		if IsKeyDown(KeyE) {
+			CameraRoll(camera, 0.03)
+		}
+
+		// Camera movement
+		if !(IsGamepadAvailable(0)) {
+			// Camera pan (for CameraFree)
+			if mode == CameraFree && IsMouseButtonDown(MouseMiddleButton) {
+				var mouseDelta = GetMouseDelta()
+				if mouseDelta.X > 0.0 {
+					CameraMoveRight(camera, 0.2, moveInWorldPlane)
+				}
+				if mouseDelta.X < 0.0 {
+					CameraMoveRight(camera, -0.2, moveInWorldPlane)
+				}
+				if mouseDelta.Y > 0.0 {
+					CameraMoveUp(camera, -0.2)
+				}
+				if mouseDelta.Y < 0.0 {
+					CameraMoveUp(camera, 0.2)
+				}
+			} else {
+				// Mouse support
+				CameraYaw(camera, -mousePositionDelta.X*0.003, rotateAroundTarget)
+				CameraPitch(camera, -mousePositionDelta.Y*0.003, lockView, rotateAroundTarget, rotateUp)
+			}
+
+			// Keyboard support
+			if IsKeyDown(KeyW) {
+				CameraMoveForward(camera, 0.09, moveInWorldPlane)
+			}
+			if IsKeyDown(KeyA) {
+				CameraMoveRight(camera, -0.09, moveInWorldPlane)
+			}
+			if IsKeyDown(KeyS) {
+				CameraMoveForward(camera, -0.09, moveInWorldPlane)
+			}
+			if IsKeyDown(KeyD) {
+				CameraMoveRight(camera, 0.09, moveInWorldPlane)
+			}
+		} else {
+			// Gamepad controller support
+			CameraYaw(camera, -(GetGamepadAxisMovement(0, GamepadAxisRightX)*float32(2))*0.003, rotateAroundTarget)
+			CameraPitch(camera, -(GetGamepadAxisMovement(0, GamepadAxisRightY)*float32(2))*0.003, lockView, rotateAroundTarget, rotateUp)
+
+			if GetGamepadAxisMovement(0, GamepadAxisLeftY) <= -0.25 {
+				CameraMoveForward(camera, 0.09, moveInWorldPlane)
+			}
+			if GetGamepadAxisMovement(0, GamepadAxisLeftX) <= -0.25 {
+				CameraMoveRight(camera, -0.09, moveInWorldPlane)
+			}
+			if GetGamepadAxisMovement(0, GamepadAxisLeftY) >= 0.25 {
+				CameraMoveForward(camera, -0.09, moveInWorldPlane)
+			}
+			if GetGamepadAxisMovement(0, GamepadAxisLeftX) >= 0.25 {
+				CameraMoveRight(camera, 0.09, moveInWorldPlane)
+			}
+		}
+
+		if mode == CameraFree {
+			if IsKeyDown(KeySpace) {
+				CameraMoveUp(camera, 0.09)
+			}
+			if IsKeyDown(KeyLeftControl) {
+				CameraMoveUp(camera, -0.09)
+			}
+		}
+	}
+
+	if mode == CameraThirdPerson || mode == CameraOrbital || mode == CameraFree {
+		// Zoom target distance
+		CameraMoveToTarget(camera, -GetMouseWheelMove())
+		if IsKeyPressed(KeyKpSubtract) {
+			CameraMoveToTarget(camera, 2.0)
+		}
+		if IsKeyPressed(KeyKpAdd) {
+			CameraMoveToTarget(camera, -2.0)
+		}
+	}
 }
 
-// UpdateCameraPro - Update camera movement/rotation
+// UpdateCameraPro - Update camera movement, movement/rotation values should be provided by user
 func UpdateCameraPro(camera *Camera, movement Vector3, rotation Vector3, zoom float32) {
-	ccamera := camera.cptr()
-	C.UpdateCameraPro(ccamera, *movement.cptr(), *rotation.cptr(), C.float(zoom))
+	// Required values
+	// movement.X - Move forward/backward
+	// movement.Y - Move right/left
+	// movement.Z - Move up/down
+	// rotation.X - yaw
+	// rotation.Y - pitch
+	// rotation.Z - roll
+	// zoom - Move towards target
+
+	lockView := uint8(1)
+	rotateAroundTarget := uint8(0)
+	rotateUp := uint8(0)
+	moveInWorldPlane := uint8(1)
+
+	// Camera rotation
+	CameraPitch(camera, -rotation.Y*(Pi/180.0), lockView, rotateAroundTarget, rotateUp)
+	CameraYaw(camera, -rotation.X*(Pi/180.0), rotateAroundTarget)
+	CameraRoll(camera, rotation.Z*(Pi/180.0))
+
+	// Camera movement
+	CameraMoveForward(camera, movement.X, moveInWorldPlane)
+	CameraMoveRight(camera, movement.Y, moveInWorldPlane)
+	CameraMoveUp(camera, movement.Z)
+
+	// Zoom target distance
+	CameraMoveToTarget(camera, zoom)
 }