BloodMagic/src/main/java/wayoftime/bloodmagic/client/render/RenderResizableCuboid.java

package wayoftime.bloodmagic.client.render;

import java.util.Arrays;

import com.mojang.blaze3d.matrix.MatrixStack;
import com.mojang.blaze3d.vertex.IVertexBuilder;

import net.minecraft.client.Minecraft;
import net.minecraft.client.renderer.entity.EntityRendererManager;
import net.minecraft.client.renderer.texture.TextureAtlasSprite;
import net.minecraft.util.Direction;
import net.minecraft.util.Direction.Axis;
import net.minecraft.util.Direction.AxisDirection;
import net.minecraft.util.math.vector.Matrix3f;
import net.minecraft.util.math.vector.Matrix4f;
import net.minecraft.util.math.vector.Vector3d;
import net.minecraft.util.math.vector.Vector3f;
import net.minecraft.util.math.vector.Vector3i;
import wayoftime.bloodmagic.client.render.BloodMagicRenderer.Model3D;

/**
 * Adapted from BuildCraft
 */
public class RenderResizableCuboid
{
	public static final RenderResizableCuboid INSTANCE = new RenderResizableCuboid();
	private static final Vector3f VEC_ZERO = new Vector3f(0, 0, 0);
	private static final int U_MIN = 0;
	private static final int U_MAX = 1;
	private static final int V_MIN = 2;
	private static final int V_MAX = 3;

	protected EntityRendererManager manager = Minecraft.getInstance().getRenderManager();

	private static Vector3f withValue(Vector3f vector, Axis axis, float value)
	{
		if (axis == Axis.X)
		{
			return new Vector3f(value, vector.getY(), vector.getZ());
		} else if (axis == Axis.Y)
		{
			return new Vector3f(vector.getX(), value, vector.getZ());
		} else if (axis == Axis.Z)
		{
			return new Vector3f(vector.getX(), vector.getY(), value);
		}
		throw new RuntimeException("Was given a null axis! That was probably not intentional, consider this a bug! (Vector = " + vector + ")");
	}

	public static double getValue(Vector3d vector, Axis axis)
	{
		if (axis == Axis.X)
		{
			return vector.x;
		} else if (axis == Axis.Y)
		{
			return vector.y;
		} else if (axis == Axis.Z)
		{
			return vector.z;
		}
		throw new RuntimeException("Was given a null axis! That was probably not intentional, consider this a bug! (Vector = " + vector + ")");
	}

	public void renderCube(Model3D cube, MatrixStack matrix, IVertexBuilder buffer, int argb, int light, int overlay)
	{
		float red = BloodMagicRenderer.getRed(argb);
		float green = BloodMagicRenderer.getGreen(argb);
		float blue = BloodMagicRenderer.getBlue(argb);
		float alpha = BloodMagicRenderer.getAlpha(argb);
		Vector3d size = new Vector3d(cube.sizeX(), cube.sizeY(), cube.sizeZ());
		matrix.push();
		matrix.translate(cube.minX, cube.minY, cube.minZ);
		MatrixStack.Entry lastMatrix = matrix.getLast();
		Matrix4f matrix4f = lastMatrix.getMatrix();
		Matrix3f normal = lastMatrix.getNormal();
		for (Direction face : Direction.values())
		{
			if (cube.shouldSideRender(face))
			{
				int ordinal = face.ordinal();
				TextureAtlasSprite sprite = cube.textures[ordinal];
				if (sprite != null)
				{
					Axis u = face.getAxis() == Axis.X ? Axis.Z : Axis.X;
					Axis v = face.getAxis() == Axis.Y ? Axis.Z : Axis.Y;
					float other = face.getAxisDirection() == AxisDirection.POSITIVE
							? (float) getValue(size, face.getAxis())
							: 0;

					// Swap the face if this is positive: the renderer returns indexes that ALWAYS
					// are for the negative face, so light it properly this way
					face = face.getAxisDirection() == AxisDirection.NEGATIVE ? face : face.getOpposite();
					Direction opposite = face.getOpposite();

					float minU = sprite.getMinU();
					float maxU = sprite.getMaxU();
					// Flip the v
					float minV = sprite.getMaxV();
					float maxV = sprite.getMinV();
					double sizeU = getValue(size, u);
					double sizeV = getValue(size, v);
					// TODO: Look into this more, as it makes tiling of multiple objects not render
					// properly if they don't fit the full texture.
					// Example: Mechanical pipes rendering water or lava, makes it relatively easy
					// to see the texture artifacts
					for (int uIndex = 0; uIndex < sizeU; uIndex++)
					{
						float[] baseUV = new float[] { minU, maxU, minV, maxV };
						double addU = 1;
						// If the size of the texture is greater than the cuboid goes on for then make
						// sure the texture positions are lowered
						if (uIndex + addU > sizeU)
						{
							addU = sizeU - uIndex;
							baseUV[U_MAX] = baseUV[U_MIN] + (baseUV[U_MAX] - baseUV[U_MIN]) * (float) addU;
						}
						for (int vIndex = 0; vIndex < sizeV; vIndex++)
						{
							float[] uv = Arrays.copyOf(baseUV, 4);
							double addV = 1;
							if (vIndex + addV > sizeV)
							{
								addV = sizeV - vIndex;
								uv[V_MAX] = uv[V_MIN] + (uv[V_MAX] - uv[V_MIN]) * (float) addV;
							}
							float[] xyz = new float[] { uIndex, (float) (uIndex + addU), vIndex,
									(float) (vIndex + addV) };

							renderPoint(matrix4f, normal, buffer, face, u, v, other, uv, xyz, true, false, red, green, blue, alpha, light, overlay);
							renderPoint(matrix4f, normal, buffer, face, u, v, other, uv, xyz, true, true, red, green, blue, alpha, light, overlay);
							renderPoint(matrix4f, normal, buffer, face, u, v, other, uv, xyz, false, true, red, green, blue, alpha, light, overlay);
							renderPoint(matrix4f, normal, buffer, face, u, v, other, uv, xyz, false, false, red, green, blue, alpha, light, overlay);

							renderPoint(matrix4f, normal, buffer, opposite, u, v, other, uv, xyz, false, false, red, green, blue, alpha, light, overlay);
							renderPoint(matrix4f, normal, buffer, opposite, u, v, other, uv, xyz, false, true, red, green, blue, alpha, light, overlay);
							renderPoint(matrix4f, normal, buffer, opposite, u, v, other, uv, xyz, true, true, red, green, blue, alpha, light, overlay);
							renderPoint(matrix4f, normal, buffer, opposite, u, v, other, uv, xyz, true, false, red, green, blue, alpha, light, overlay);
						}
					}
				}
			}
		}
		matrix.pop();
	}

	private void renderPoint(Matrix4f matrix4f, Matrix3f normal, IVertexBuilder buffer, Direction face, Axis u, Axis v, float other, float[] uv, float[] xyz, boolean minU, boolean minV, float red, float green, float blue, float alpha, int light, int overlay)
	{
		int U_ARRAY = minU ? U_MIN : U_MAX;
		int V_ARRAY = minV ? V_MIN : V_MAX;
		Vector3f vertex = withValue(VEC_ZERO, u, xyz[U_ARRAY]);
		vertex = withValue(vertex, v, xyz[V_ARRAY]);
		vertex = withValue(vertex, face.getAxis(), other);
		Vector3i normalForFace = face.getDirectionVec();
		// TODO: Figure out how and why this works, it gives about the same brightness
		// as we used to have but I don't understand why/how
		float adjustment = 2.5F;
		Vector3f norm = new Vector3f(normalForFace.getX() + adjustment, normalForFace.getY() + adjustment, normalForFace.getZ() + adjustment);
		norm.normalize();
		buffer.pos(matrix4f, vertex.getX(), vertex.getY(), vertex.getZ()).color(red, green, blue, alpha).tex(uv[U_ARRAY], uv[V_ARRAY]).overlay(overlay).lightmap(light).normal(normal, norm.getX(), norm.getY(), norm.getZ()).endVertex();
	}
}