Perspective: Add modelToCanvas

This has significantly less overhead than repeatedly calling
localToCanvas, and may be vectorized in the future by a smarter jit

runelite-api/src/main/java/net/runelite/api/Perspective.java

@@ -148,7 +148,74 @@ public class Perspective
 		}
 
 		return null;
+	}
 
+	/**
+	 * Translates a model's vertices into 2d space
+	 */
+	public static void modelToCanvas(Client client, int end, int x3dCenter, int y3dCenter, int z3dCenter, int rotate, int[] x3d, int[] y3d, int[] z3d, int[] x2d, int[] y2d)
+	{
+		final int
+			cameraPitch = client.getCameraPitch(),
+			cameraYaw = client.getCameraYaw(),
+
+			pitchSin = SINE[cameraPitch],
+			pitchCos = COSINE[cameraPitch],
+			yawSin = SINE[cameraYaw],
+			yawCos = COSINE[cameraYaw],
+			rotateSin = SINE[rotate],
+			rotateCos = COSINE[rotate],
+
+			cx = x3dCenter - client.getCameraX(),
+			cy = y3dCenter - client.getCameraY(),
+			cz = z3dCenter - client.getCameraZ(),
+
+			viewportXMiddle = client.getViewportWidth() / 2,
+			viewportYMiddle = client.getViewportHeight() / 2,
+			viewportXOffset = client.getViewportXOffset(),
+			viewportYOffset = client.getViewportYOffset(),
+
+			zoom3d = client.getScale();
+
+		for (int i = 0; i < end; i++)
+		{
+			int x = x3d[i];
+			int y = y3d[i];
+			int z = z3d[i];
+
+			if (rotate != 0)
+			{
+				int x0 = x;
+				x = x0 * rotateCos + y * rotateSin >> 16;
+				y = y * rotateCos - x0 * rotateSin >> 16;
+			}
+
+			x += cx;
+			y += cy;
+			z += cz;
+
+			final int
+				x1 = x * yawCos + y * yawSin >> 16,
+				y1 = y * yawCos - x * yawSin >> 16,
+				y2 = z * pitchCos - y1 * pitchSin >> 16,
+				z1 = y1 * pitchCos + z * pitchSin >> 16;
+
+			int viewX, viewY;
+
+			if (z1 < 50)
+			{
+				viewX = Integer.MIN_VALUE;
+				viewY = Integer.MIN_VALUE;
+			}
+			else
+			{
+				viewX = (viewportXMiddle + x1 * zoom3d / z1) + viewportXOffset;
+				viewY = (viewportYMiddle + y2 * zoom3d / z1) + viewportYOffset;
+			}
+
+			x2d[i] = viewX;
+			y2d[i] = viewY;
+		}
 	}
 
 	/**