main/debug: Make the frame timing graph a sliding window

Use memmove to shift the whole array by one measure to the left,
dropping the oldest one and adding a new one at the head.
This creates a better visual effect of a graph being produced on the right
and scrolling to the left, rather than a looping writing head that overwrites
previous data.

World.cpp

@@ -107,6 +107,9 @@ float World::castRay(float originX, float originY, float orientation) const
 	 *    the grid for the other one
 	 *  - Depending on the orientation, signs must be taken into account
 	 *    to work 360°
+	 *  - Those formulas consider regular axes (x→,y↑), however the world is
+	 *    built around left-handed axes (x→,y↓), so the rendered world is
+	 *    mirrored. This also explains some weird signs for rotations.
 	 */
 	/* Offsets to get back on the grid from the ray's origin. */
 	float hOffsetX;
@@ -148,7 +151,7 @@ float World::castRay(float originX, float originY, float orientation) const
 	if (orientation < 180) {
 		vOffsetX = ceilf(originX);
 		vOffsetY = ceilf(originX) - originX;
-        vDir = +1;
+		vDir = 1;
 		vRound = 0;
 	} else {
 		vOffsetX = floorf(originX);
@@ -239,6 +242,8 @@ void World::render(sf::RenderWindow& window) const
 	window.draw(ground);
 	window.draw(ceiling);
 
+	const float worldToCamera = (player.focalLength*2)/player.sensorSize;
+
 	/*
 	 * Throw rays and draw walls over the ceiling and ground.
 	 * Only throws in the plane, which doesn't work for levels/3D.
@@ -252,7 +257,7 @@ void World::render(sf::RenderWindow& window) const
 		} else if (rayAngle > 360) {
 			rayAngle -= 360;
 		}
-        float obstacleScale = player.focalLength*2/(castRay(player.x, player.y, rayAngle)*player.sensorSize);
+		float obstacleScale = worldToCamera / castRay(player.x, player.y, rayAngle);
 		/* 2 Is wall height in meters. */
 		fillColumn(window, i, obstacleScale);
 	}
@@ -269,7 +274,7 @@ void World::step(const float& stepTime) {
 	player.rotate(player.currentRotationSpeed*stepTime);
 
 #ifdef IMGUI
-	ImGui::Begin("MapEdit");
+	if (ImGui::Begin("MapEdit")) {
 		static int blockToPlace = 1;
 
 		/*
@@ -320,7 +325,8 @@ void World::step(const float& stepTime) {
 				ImGui::PushStyleColor(ImGuiCol_Header, blockColor);
 
 				if (ImGui::Selectable("", currentBlock != BlockType::AIR, 0, ImVec2(10, 10))) {
-				map[x + w*y] = currentBlock == (BlockType)blockToPlace ? BlockType::AIR : (BlockType)blockToPlace;
+					map[x + w * y] =
+							currentBlock == (BlockType) blockToPlace ? BlockType::AIR : (BlockType) blockToPlace;
 				}
 				ImGui::PopStyleColor(2);
 				ImGui::PopID();
@@ -337,7 +343,7 @@ void World::step(const float& stepTime) {
 		ImGui::RadioButton("Window", &blockToPlace, (int) BlockType::WINDOW);
 		ImGui::Unindent();
 		ImGui::EndGroup();
-
+	}
 	ImGui::End();
 #endif
 }

main.cpp

@@ -115,7 +115,12 @@ int main()
 		ImGui::SetNextWindowBgAlpha(0.2f);
 		ImGui::Begin("FPS", nullptr ,window_flags);
 		if (fpsDataClock.getElapsedTime().asMilliseconds() > 20) {
-			frameTimings[frameCount%100] = static_cast<float>(deltaT.asMicroseconds());
+			if (frameCount >= 100) {
+				memmove(frameTimings, frameTimings + 1, 99 * sizeof(float));
+				frameTimings[99] = static_cast<float>(deltaT.asMicroseconds());
+			} else [[unlikely]] {
+				frameTimings[frameCount] = static_cast<float>(deltaT.asMicroseconds());
+			}
 			frameCount++;
 			fpsDataClock.restart();
 		}