Created CustomObjectRenderer to allow for BufferedImages to be rendered at a given Position. This supports Zoom and Rotation on all 3 axes.

src/main/java/eu/crushedpixel/replaymod/ReplayMod.java

@@ -10,10 +10,7 @@ import eu.crushedpixel.replaymod.localization.LocalizedResourcePack;
 import eu.crushedpixel.replaymod.online.authentication.AuthenticationHandler;
 import eu.crushedpixel.replaymod.recording.ConnectionEventHandler;
 import eu.crushedpixel.replaymod.registry.*;
-import eu.crushedpixel.replaymod.renderer.InvisibilityRender;
+import eu.crushedpixel.replaymod.renderer.*;
-import eu.crushedpixel.replaymod.renderer.PathPreviewRenderer;
-import eu.crushedpixel.replaymod.renderer.SafeEntityRenderer;
-import eu.crushedpixel.replaymod.renderer.SpectatorRenderer;
 import eu.crushedpixel.replaymod.replay.ReplayHandler;
 import eu.crushedpixel.replaymod.replay.ReplayProcess;
 import eu.crushedpixel.replaymod.replay.ReplaySender;
@@ -80,6 +77,7 @@ public class ReplayMod {
     public static SpectatorRenderer spectatorRenderer;
     public static TooltipRenderer tooltipRenderer;
     public static PathPreviewRenderer pathPreviewRenderer;
+    public static CustomObjectRenderer customObjectRenderer;
     public static SoundHandler soundHandler = new SoundHandler();
     public static CrosshairRenderHandler crosshairRenderHandler;
 
@@ -140,6 +138,10 @@ public class ReplayMod {
         FMLCommonHandler.instance().bus().register(pathPreviewRenderer);
         MinecraftForge.EVENT_BUS.register(pathPreviewRenderer);
 
+        customObjectRenderer = new CustomObjectRenderer();
+        FMLCommonHandler.instance().bus().register(customObjectRenderer);
+        MinecraftForge.EVENT_BUS.register(customObjectRenderer);
+
         crosshairRenderHandler = new CrosshairRenderHandler();
         FMLCommonHandler.instance().bus().register(crosshairRenderHandler);
         MinecraftForge.EVENT_BUS.register(crosshairRenderHandler);
@@ -182,7 +184,6 @@ public class ReplayMod {
         }, "localizedResourcePackLoader");
         localizedResourcePackLoader.start();
 
-
         /*
         boolean auth = false;
         try {
@@ -198,7 +199,6 @@ public class ReplayMod {
         }
         */
 
-
         if (System.getProperty("replaymod.render.file") != null) {
             final File file = new File(System.getProperty("replaymod.render.file"));
             if (!file.exists()) {

src/main/java/eu/crushedpixel/replaymod/holders/CustomImageObject.java

@@ -0,0 +1,57 @@
+package eu.crushedpixel.replaymod.holders;
+
+import eu.crushedpixel.replaymod.registry.ResourceHelper;
+import lombok.Getter;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.renderer.texture.DynamicTexture;
+import net.minecraft.util.ResourceLocation;
+
+import javax.imageio.ImageIO;
+import java.awt.image.BufferedImage;
+import java.io.File;
+import java.io.IOException;
+
+public class CustomImageObject {
+
+    public CustomImageObject(Position position, String name, File imageSource) throws IOException {
+        BufferedImage bufferedImage = ImageIO.read(imageSource);
+
+        this.textureWidth = bufferedImage.getWidth();
+        this.textureHeight = bufferedImage.getHeight();
+
+        float w;
+        float h;
+
+        if(bufferedImage.getWidth() > bufferedImage.getHeight()) {
+            w = 1;
+            h = (bufferedImage.getHeight()/(float)bufferedImage.getWidth());
+        } else {
+            w = (bufferedImage.getWidth()/(float)bufferedImage.getHeight());
+            h = 1;
+        }
+
+        this.position = new ExtendedPosition(position.getX(), position.getY(), position.getZ(), w, h);
+        this.name = name;
+
+        this.resourceLocation = new ResourceLocation("customImages/"+imageSource.getAbsolutePath());
+        this.dynamicTexture = new DynamicTexture(bufferedImage);
+    }
+
+    @Getter private ExtendedPosition position;
+    @Getter private String name;
+
+    private ResourceLocation resourceLocation;
+    private DynamicTexture dynamicTexture;
+
+    @Getter private float textureWidth, textureHeight;
+
+    public ResourceLocation getResourceLocation() {
+        if(!ResourceHelper.isRegistered(resourceLocation)) {
+            ResourceHelper.registerResource(resourceLocation);
+            Minecraft.getMinecraft().getTextureManager().loadTexture(resourceLocation, dynamicTexture);
+            dynamicTexture.updateDynamicTexture();
+        }
+
+        return resourceLocation;
+    }
+}

src/main/java/eu/crushedpixel/replaymod/holders/ExtendedPosition.java

@@ -0,0 +1,18 @@
+package eu.crushedpixel.replaymod.holders;
+
+import lombok.Data;
+
+@Data
+public class ExtendedPosition extends Position {
+
+    public ExtendedPosition(double x, double y, double z, float width, float height) {
+        super(x, y, z, 0, 0);
+        this.width = width;
+        this.height = height;
+    }
+
+    private float anchorX, anchorY;
+    private float width, height;
+    private float scale = 1f;
+
+}

src/main/java/eu/crushedpixel/replaymod/registry/ResourceHelper.java

@@ -23,7 +23,11 @@ public class ResourceHelper {
     }
 
     public static void registerResource(ResourceLocation loc) {
-        openResources.add(loc);
+        if(!openResources.contains(loc)) openResources.add(loc);
+    }
+
+    public static boolean isRegistered(ResourceLocation loc) {
+        return openResources.contains(loc);
     }
 
     public static void freeResource(ResourceLocation loc) {

src/main/java/eu/crushedpixel/replaymod/renderer/CustomObjectRenderer.java

@@ -0,0 +1,112 @@
+package eu.crushedpixel.replaymod.renderer;
+
+import eu.crushedpixel.replaymod.holders.CustomImageObject;
+import eu.crushedpixel.replaymod.holders.ExtendedPosition;
+import eu.crushedpixel.replaymod.replay.ReplayHandler;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.renderer.GlStateManager;
+import net.minecraft.client.renderer.Tessellator;
+import net.minecraft.client.renderer.WorldRenderer;
+import net.minecraft.entity.Entity;
+import net.minecraftforge.client.event.RenderWorldLastEvent;
+import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
+import org.lwjgl.opengl.GL11;
+
+/**
+ * Allows users to render custom images in the World.
+ */
+public class CustomObjectRenderer {
+
+    private static final Minecraft mc = Minecraft.getMinecraft();
+
+    @SubscribeEvent
+    public void renderCustomObjects(RenderWorldLastEvent event) {
+        if(!ReplayHandler.isInReplay()) return;
+
+        Entity entity = ReplayHandler.getCameraEntity();
+        if(entity == null) return;
+
+        double doubleX = entity.posX;
+        double doubleY = entity.posY;
+        double doubleZ = entity.posZ;
+
+        GlStateManager.pushAttrib();
+        GlStateManager.pushMatrix();
+
+        GlStateManager.disableLighting();
+        GlStateManager.enableBlend();
+
+        GlStateManager.disableTexture2D();
+
+        //do stuff here
+        for(CustomImageObject object : ReplayHandler.getCustomImageObjects()) {
+            drawCustomImageObject(doubleX, doubleY, doubleZ, object);
+        }
+
+        GlStateManager.enableTexture2D();
+        GlStateManager.enableLighting();
+
+        GlStateManager.disableBlend();
+        GlStateManager.popAttrib();
+        GlStateManager.popMatrix();
+    }
+
+    private void drawCustomImageObject(double playerX, double playerY, double playerZ, CustomImageObject customImageObject) {
+        GlStateManager.pushMatrix();
+        GlStateManager.enableTexture2D();
+        GlStateManager.enableLighting();
+        GlStateManager.disableLighting();
+        GlStateManager.enableAlpha();
+
+        GlStateManager.disableBlend();
+
+        Tessellator tessellator = Tessellator.getInstance();
+        WorldRenderer renderer = tessellator.getWorldRenderer();
+
+        mc.renderEngine.bindTexture(customImageObject.getResourceLocation());
+
+        ExtendedPosition objectPosition = customImageObject.getPosition();
+
+        double x = objectPosition.getX() - playerX;
+        double y = objectPosition.getY() - playerY;
+        double z = objectPosition.getZ() - playerZ;
+
+        GL11.glNormal3f(0, 1, 0);
+
+        GlStateManager.translate(x, y + 1.4, z);
+
+        GlStateManager.rotate(-objectPosition.getYaw(), 0, 1, 0);
+        GlStateManager.rotate(objectPosition.getRoll(), 0, 0, 1);
+        GlStateManager.rotate(objectPosition.getPitch(), 1, 0, 0);
+
+        renderer.setColorRGBA_F(1, 1, 1, 0.5f);
+
+        float width = objectPosition.getWidth() * objectPosition.getScale();
+        float height = objectPosition.getHeight() * objectPosition.getScale();
+
+        float minX = -width/2 + objectPosition.getAnchorX();
+        float maxX = width/2 + objectPosition.getAnchorX();
+        float minY = -height/2 + objectPosition.getAnchorY();
+        float maxY = height/2 + objectPosition.getAnchorY();
+
+        renderer.startDrawingQuads();
+
+        renderer.addVertexWithUV(minX, minY, 0, 1, 1);
+        renderer.addVertexWithUV(minX, maxY, 0, 1, 0);
+        renderer.addVertexWithUV(maxX, maxY, 0, 0, 0);
+        renderer.addVertexWithUV(maxX, minY, 0, 0, 1);
+
+        renderer.addVertexWithUV(maxX, maxY, 0, 0, 0);
+        renderer.addVertexWithUV(minX, maxY, 0, 1, 0);
+        renderer.addVertexWithUV(minX, minY, 0, 1, 1);
+        renderer.addVertexWithUV(maxX, minY, 0, 0, 1);
+
+        tessellator.draw();
+        renderer.setTranslation(0, 0, 0);
+
+        GlStateManager.disableAlpha();
+        GlStateManager.disableTexture2D();
+        GlStateManager.enableLighting();
+        GlStateManager.popMatrix();
+    }
+}

src/main/java/eu/crushedpixel/replaymod/replay/ReplayHandler.java

@@ -52,6 +52,8 @@ public class ReplayHandler {
 
     private static KeyframeSet[] keyframeRepository = new KeyframeSet[]{};
 
+    private static List<CustomImageObject> customImageObjects = new ArrayList<CustomImageObject>();
+
     /**
      * The file currently being played.
      */
@@ -734,4 +736,12 @@ public class ReplayHandler {
 
         setRealTimelineCursor(newCursorPos);
     }
+
+    public static List<CustomImageObject> getCustomImageObjects() {
+        return customImageObjects;
+    }
+
+    public static void addCustomImageObject(CustomImageObject object) {
+        customImageObjects.add(object);
+    }
 }