Wall Penetrating

[poopoodice]

Catch up with the last topic with rendering, this is something that I took a while to learn from nothing to this stage.

(I only shoot from right side)

    public static List<Pair<BlockRayTraceResult, Float>> rayTraceAndPenetrateBlocks4(World world, List<Vector3d> vecs, float health, Function<BlockState, Float> getHealthReduction)
    {
        List<Pair<BlockRayTraceResult, Float>> results = new ArrayList<>();
        if (vecs.isEmpty())
            return results;
        Vector3d startVec = vecs.get(0);
        for (int i=0;i<vecs.size()-1;i++)
        {
            Vector3d vec = vecs.get(i);
            Vector3d next = vecs.get(i + 1);
            BlockPos pos = new BlockPos(vec);
            BlockPos pos2 = new BlockPos(next);
            BlockState blockstate = world.getBlockState(pos);
            BlockState blockstate2 = world.getBlockState(pos2);
            if (blockstate.getBlock() instanceof BarrierBlock && blockstate2.getBlock() instanceof BarrierBlock)
                continue;
            VoxelShape blockShape = blockstate.getCollisionShape(world, pos, ISelectionContext.dummy());
            VoxelShape blockShape2 = blockstate2.getCollisionShape(world, pos2, ISelectionContext.dummy());
            BlockRayTraceResult blockResult;
            boolean empty = blockShape.isEmpty() || blockShape.toBoundingBoxList().stream().noneMatch((bb) -> bb.offset(pos).contains(vec));
            boolean empty2 = blockShape2.isEmpty() || blockShape2.toBoundingBoxList().stream().noneMatch((bb) -> bb.offset(pos2).contains(next));
            if ((isRayTraceIgnorableBlock(blockstate, blockShape) && isRayTraceIgnorableBlock(blockstate2, blockShape2)))
                continue;
            if (empty && !empty2)
                blockResult = world.rayTraceBlocks(vec, next, pos2, blockShape2, blockstate2);
            else if (!empty && empty2)
                blockResult = world.rayTraceBlocks(next, vec, pos, blockShape, blockstate);
            else
                blockResult = world.rayTraceBlocks(vec, next, pos, blockShape, blockstate);

            if (blockResult != null)
            {
                health -= getHealthReduction.apply(blockstate);
                results.add(new Pair<>(blockResult, (float) startVec.distanceTo(blockResult.getHitVec())));
                if (health <= 0)
                    break;
            }
        }
        return results;
    }

	    public static List<Vector3d> getAllVectors2(Vector3d startVec, Vector3d endVec, int distance)
    {
        List<Vector3d> vecs = new ArrayList<>();
        Vector3d step = endVec.subtract(startVec).normalize();
        int rayTraceCount = 20;
        for (int i=0;i<distance;i++)
            for (int j=0;j<rayTraceCount;j++)
                vecs.add(startVec.add(step.scale(i).add(step.scale((float) j / (float) rayTraceCount))));
        return vecs;
    }

The vecs passed into the first method comes from the second method.

The concept is to gather a collection of vectors, and the do ray trace between each of them. The first method can be a lot more simplified but not on my case since I also do entity penetrations, with damage calculations...etc.

Anyways, if you only do normal raytracing what you will get will be something like:

 

Black Block represents a solid block

Gray Block represents air or empty shaped block

Green dots represents the positions we ray trace between.

Blue dots represents the ray trace hit result.

As you can see, the ray trace hit will not (unlikely) hit the surface when coming out of a block, therefore we need to detect the situation and ray trace back wards:

So we get the "entering" and "exiting" points.

 

Here comes the rendering part once again, once you have let the client know where is hit you can perform the rendering based on the ray trace result.

    private static void renderObjectAt(Minecraft minecraft, EnvironmentObjectEffect object, World world, MatrixStack stack, float size, float offsetScale, ResourceLocation texture)
    {
        Vector3d vec = object.getVec();
        stack.push();
        Vector3d view = Minecraft.getInstance().gameRenderer.getActiveRenderInfo().getProjectedView();
        double x = vec.x - view.getX();
        double y = vec.y - view.getY();
        double z = vec.z - view.getZ();
        if (Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2) + Math.pow(z, 2)) > 100.0F)
            return;
        stack.translate(x, y, z);
        Direction direction = object.getDirection();
        if (direction != null)
        {
            Vector3i offset = direction.getDirectionVec();
            stack.translate(offset.getX() * offsetScale, offset.getY() * offsetScale, offset.getZ() * offsetScale);
            rotateByDirection(stack, direction);
        }
        else
        {
            stack.rotate(minecraft.getRenderManager().getCameraOrientation());
            stack.rotate(Vector3f.ZP.rotationDegrees(180.0F));
        }
        if (object.doBlend())
        {
            Color colour = new Color(world.getBlockState(object.getPos()).getMaterialColor(world, object.getPos()).colorValue);
            RenderSystem.color4f(colour.getRed() / 255.0F, colour.getGreen() / 255.0F, colour.getBlue() / 255.0F, object.getTransparency());
        }
        AVAClientUtil.blit(stack, texture, -size, -size, size, size);
        RenderSystem.color4f(1.0F, 1.0F, 1.0f, 1.0F);
        stack.pop();
    }

direction is facing from the BlockRayTraceResult, and doBlend is true so it will look better with the block behind it.

The offset is required otherwise it will be on the same level with the block, the offset scale is a small number so there will not be an obvious gap between the wall and the texture object, the scale also prevents multiple objects overlap, for example when I have multiple "renderable objects":

            for (EnvironmentObjectEffect bulletHole : AVACommonUtil.cap(world).getBulletHoles())
                renderObjectAt(minecraft, bulletHole, world, stack, 0.075F, 0.01F, BULLET_HOLE);
            for (EnvironmentObjectEffect blood : AVACommonUtil.cap(world).getBloods())
                renderObjectAt(minecraft, blood, world, stack, 0.525F, 0.011F, BLOOD);
            for (EnvironmentObjectEffect knifeHole : AVACommonUtil.cap(world).getKnifeHoles())
                renderObjectAt(minecraft, knifeHole, world, stack, 0.095F, 0.0105F, KNIFE_HOLE);
            for (EnvironmentObjectEffect grenadeMark : AVACommonUtil.cap(world).getGrenadeMarks())
                renderObjectAt(minecraft, grenadeMark, world, stack, 2.5F, 0.075F, GRENADE_MARK);

bullet hole < knife hole < blood < grenade mark (level)

Red Image

Spoiler