Rework of HUD element system

Allows configuration because that's probably a good thing. The values in
the json config are percentages of the screen.

src/main/java/WayofTime/bloodmagic/client/hud/element/ElementDemonAura.java

@@ -0,0 +1,78 @@
+package WayofTime.bloodmagic.client.hud.element;
+
+import WayofTime.bloodmagic.BloodMagic;
+import WayofTime.bloodmagic.proxy.ClientProxy;
+import WayofTime.bloodmagic.soul.EnumDemonWillType;
+import WayofTime.bloodmagic.util.Utils;
+import com.google.common.collect.Lists;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.gui.ScaledResolution;
+import net.minecraft.client.renderer.GlStateManager;
+import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.util.ResourceLocation;
+
+import java.util.List;
+
+public class ElementDemonAura extends HUDElement {
+
+    private static final ResourceLocation BAR_LOCATION = new ResourceLocation(BloodMagic.MODID, "textures/hud/bars.png");
+
+    private final List<EnumDemonWillType> orderedTypes = Lists.newArrayList(
+            EnumDemonWillType.DEFAULT,
+            EnumDemonWillType.CORROSIVE,
+            EnumDemonWillType.STEADFAST,
+            EnumDemonWillType.DESTRUCTIVE,
+            EnumDemonWillType.VENGEFUL
+    );
+
+    public ElementDemonAura() {
+        super(80, 46);
+    }
+
+    @Override
+    public void draw(ScaledResolution resolution, float partialTicks, int drawX, int drawY) {
+        Minecraft minecraft = Minecraft.getMinecraft();
+        EntityPlayer player = minecraft.player;
+
+        minecraft.getTextureManager().bindTexture(BAR_LOCATION);
+        GlStateManager.color(1.0F, 1.0F, 1.0F);
+        this.drawTexturedModalRect(drawX, drawY, 0, 210, 80, 46);
+
+        double maxAmount = Utils.getDemonWillResolution(player);
+
+        int i = 0;
+        for (EnumDemonWillType type : orderedTypes) {
+            i++;
+            GlStateManager.color(1.0F, 1.0F, 1.0F);
+            minecraft.getTextureManager().bindTexture(BAR_LOCATION);
+            int textureXOffset = (i > 3) ? (i - 3) : (3 - i);
+            int maxBarSize = 30 - 2 * textureXOffset;
+
+            double amount = ClientProxy.currentAura == null ? 0 : ClientProxy.currentAura.getWill(type);
+            double ratio = Math.max(Math.min(amount / maxAmount, 1), 0);
+
+            double width = maxBarSize * ratio * 2;
+            double height = 2;
+            double x = drawX + 2 * textureXOffset + 10;
+            double y = drawY + 4 * i + 10;
+
+            double textureX = 2 * textureXOffset + 2 * 42;
+            double textureY = 4 * i + 220;
+
+            this.drawTexturedModalRect(x, y, textureX, textureY, width, height);
+
+            if (player.isSneaking()) {
+                GlStateManager.pushMatrix();
+                GlStateManager.translate(x - 2 * textureXOffset + 70, (y - 1), 0);
+                GlStateManager.scale(0.5, 0.5, 1);
+                minecraft.fontRenderer.drawStringWithShadow(String.valueOf((int) amount), 0, 2, 0xffffff);
+                GlStateManager.popMatrix();
+            }
+        }
+    }
+
+    @Override
+    public boolean shouldRender(Minecraft minecraft) {
+        return Utils.canPlayerSeeDemonWill(Minecraft.getMinecraft().player);
+    }
+}