Core: Allow moving the camera target via arrow keys

It's not as versatile as a full panning mode, but also much simpler.

Core/NativeClient/C_Camera.lua

@@ -30,6 +30,7 @@ local C_Camera = {
 	MIN_ORBIT_DISTANCE = 45,
 	MAX_ORBIT_DISTANCE = 80,
 	targetWorldPosition = Vector3D(0, 0, 0),
+	TARGET_DEBUG_STEPSIZE_IN_WORLD_UNITS = 12,
 }
 
 function C_Camera.CreatePerspectiveProjection(verticalFieldOfViewInDegrees, aspectRatio, zNearDistance, zFarDistance)

Core/NativeClient/NativeClient.lua

@@ -1,3 +1,4 @@
+local bit = require("bit")
 local ffi = require("ffi")
 local glfw = require("glfw")
 local interop = require("interop")
@@ -6,6 +7,7 @@ local uv = require("uv")
 local C_Camera = require("Core.NativeClient.C_Camera")
 local C_Cursor = require("Core.NativeClient.C_Cursor")
 local Renderer = require("Core.NativeClient.Renderer")
+local Vector3D = require("Core.VectorMath.Vector3D")
 
 local Box = require("Core.NativeClient.DebugDraw.Box")
 local Cone = require("Core.NativeClient.DebugDraw.Cone")
@@ -261,7 +263,38 @@ function NativeClient:SCROLL_STATUS_CHANGED(eventID, payload)
 end
 
 function NativeClient:KEYPRESS_STATUS_CHANGED(eventID, payload)
-	print("KEYPRESS_STATUS_CHANGED")
+	local GLFW_KEY_LEFT = glfw.bindings.glfw_find_constant("GLFW_KEY_LEFT")
+	local GLFW_KEY_RIGHT = glfw.bindings.glfw_find_constant("GLFW_KEY_RIGHT")
+	local GLFW_KEY_DOWN = glfw.bindings.glfw_find_constant("GLFW_KEY_DOWN")
+	local GLFW_KEY_UP = glfw.bindings.glfw_find_constant("GLFW_KEY_UP")
+	local GLFW_MOD_SHIFT = glfw.bindings.glfw_find_constant("GLFW_MOD_SHIFT")
+	local GLFW_PRESS = glfw.bindings.glfw_find_constant("GLFW_PRESS")
+	local wasKeyPressed = tonumber(payload.key_details.action) == GLFW_PRESS
+	if not wasKeyPressed then
+		return
+	end
+
+	local isModifiedBySHIFT = bit.band(payload.key_details.mods, GLFW_MOD_SHIFT) == 1
+	if not isModifiedBySHIFT then
+		return
+	end
+
+	local wasLeftKey = payload.key_details.key == GLFW_KEY_LEFT
+	local wasRightKey = payload.key_details.key == GLFW_KEY_RIGHT
+	local wasUpKey = payload.key_details.key == GLFW_KEY_UP
+	local wasDownKey = payload.key_details.key == GLFW_KEY_DOWN
+	local movementDirectionX = wasLeftKey and -1 or 0
+	movementDirectionX = wasRightKey and 1 or movementDirectionX
+	local movementDirectionZ = wasUpKey and 1 or 0
+	movementDirectionZ = wasDownKey and -1 or movementDirectionZ
+
+	local movementDistanceInWorldUnits = C_Camera.TARGET_DEBUG_STEPSIZE_IN_WORLD_UNITS
+	local translation = Vector3D(
+		movementDirectionX * movementDistanceInWorldUnits,
+		0,
+		movementDirectionZ * movementDistanceInWorldUnits
+	)
+	C_Camera.targetWorldPosition = C_Camera.targetWorldPosition:Add(translation)
 end
 
 function NativeClient:UNICODE_INPUT_RECEIVED(eventID, payload)

Tests/NativeClient/NativeClient.spec.lua

@@ -4,6 +4,7 @@ local glfw = require("glfw")
 local C_Camera = require("Core.NativeClient.C_Camera")
 local C_Cursor = require("Core.NativeClient.C_Cursor")
 local NativeClient = require("Core.NativeClient.NativeClient")
+local Vector3D = require("Core.VectorMath.Vector3D")
 
 describe("NativeClient", function()
 	describe("CURSOR_MOVED", function()
@@ -479,4 +480,79 @@ describe("NativeClient", function()
 			end
 		)
 	end)
+
+	describe("KEYPRESS_STATUS_CHANGED", function()
+		local originalCameraTarget = C_Camera.GetTargetPosition()
+		after(function()
+			C_Camera.SetTargetPosition(originalCameraTarget)
+		end)
+
+		it("should adjust the camera target if SHIFT + LEFT was pressed", function()
+			local event = ffi.new("deferred_event_t")
+			event.key_details.key = glfw.bindings.glfw_find_constant("GLFW_KEY_LEFT")
+			event.key_details.action = glfw.bindings.glfw_find_constant("GLFW_PRESS")
+			event.key_details.mods = glfw.bindings.glfw_find_constant("GLFW_MOD_SHIFT")
+
+			NativeClient:KEYPRESS_STATUS_CHANGED("KEYPRESS_STATUS_CHANGED", event)
+
+			local newCameraTarget = C_Camera.GetTargetPosition()
+			local expectedTranslation = Vector3D(-C_Camera.TARGET_DEBUG_STEPSIZE_IN_WORLD_UNITS, 0, 0)
+			local expectedCameraTarget = originalCameraTarget:Add(expectedTranslation)
+
+			assertEquals(newCameraTarget.x, expectedCameraTarget.x)
+			assertEquals(newCameraTarget.y, expectedCameraTarget.y)
+			assertEquals(newCameraTarget.z, expectedCameraTarget.z)
+		end)
+
+		it("should adjust the camera target if SHIFT + RIGHT was pressed", function()
+			local event = ffi.new("deferred_event_t")
+			event.key_details.key = glfw.bindings.glfw_find_constant("GLFW_KEY_RIGHT")
+			event.key_details.action = glfw.bindings.glfw_find_constant("GLFW_PRESS")
+			event.key_details.mods = glfw.bindings.glfw_find_constant("GLFW_MOD_SHIFT")
+
+			NativeClient:KEYPRESS_STATUS_CHANGED("KEYPRESS_STATUS_CHANGED", event)
+
+			local newCameraTarget = C_Camera.GetTargetPosition()
+			local expectedTranslation = Vector3D(C_Camera.TARGET_DEBUG_STEPSIZE_IN_WORLD_UNITS, 0, 0)
+			local expectedCameraTarget = originalCameraTarget:Add(expectedTranslation)
+
+			assertEquals(newCameraTarget.x, expectedCameraTarget.x)
+			assertEquals(newCameraTarget.y, expectedCameraTarget.y)
+			assertEquals(newCameraTarget.z, expectedCameraTarget.z)
+		end)
+
+		it("should adjust the camera target if SHIFT + UP was pressed", function()
+			local event = ffi.new("deferred_event_t")
+			event.key_details.key = glfw.bindings.glfw_find_constant("GLFW_KEY_UP")
+			event.key_details.action = glfw.bindings.glfw_find_constant("GLFW_PRESS")
+			event.key_details.mods = glfw.bindings.glfw_find_constant("GLFW_MOD_SHIFT")
+
+			NativeClient:KEYPRESS_STATUS_CHANGED("KEYPRESS_STATUS_CHANGED", event)
+
+			local newCameraTarget = C_Camera.GetTargetPosition()
+			local expectedTranslation = Vector3D(0, 0, C_Camera.TARGET_DEBUG_STEPSIZE_IN_WORLD_UNITS)
+			local expectedCameraTarget = originalCameraTarget:Add(expectedTranslation)
+
+			assertEquals(newCameraTarget.x, expectedCameraTarget.x)
+			assertEquals(newCameraTarget.y, expectedCameraTarget.y)
+			assertEquals(newCameraTarget.z, expectedCameraTarget.z)
+		end)
+
+		it("should adjust the camera target if SHIFT + DOWN was pressed", function()
+			local event = ffi.new("deferred_event_t")
+			event.key_details.key = glfw.bindings.glfw_find_constant("GLFW_KEY_DOWN")
+			event.key_details.action = glfw.bindings.glfw_find_constant("GLFW_PRESS")
+			event.key_details.mods = glfw.bindings.glfw_find_constant("GLFW_MOD_SHIFT")
+
+			NativeClient:KEYPRESS_STATUS_CHANGED("KEYPRESS_STATUS_CHANGED", event)
+
+			local newCameraTarget = C_Camera.GetTargetPosition()
+			local expectedTranslation = Vector3D(0, 0, -C_Camera.TARGET_DEBUG_STEPSIZE_IN_WORLD_UNITS)
+			local expectedCameraTarget = originalCameraTarget:Add(expectedTranslation)
+
+			assertEquals(newCameraTarget.x, expectedCameraTarget.x)
+			assertEquals(newCameraTarget.y, expectedCameraTarget.y)
+			assertEquals(newCameraTarget.z, expectedCameraTarget.z)
+		end)
+	end)
 end)