package com.mojang.blaze3d;

import net.fabricmc.api.EnvType;
import net.fabricmc.api.Environment;

@Environment(EnvType.CLIENT)
public enum PrimitiveTopology {
	LINES(2, 2, false),
	DEBUG_LINES(2, 2, false),
	DEBUG_LINE_STRIP(2, 1, true),
	POINTS(1, 1, false),
	TRIANGLES(3, 3, false),
	TRIANGLE_STRIP(3, 1, true),
	TRIANGLE_FAN(3, 1, true),
	QUADS(4, 4, false);

	public final int primitiveLength;
	public final int primitiveStride;
	public final boolean connectedPrimitives;

	private PrimitiveTopology(final int primitiveLength, final int primitiveStride, final boolean connectedPrimitives) {
		this.primitiveLength = primitiveLength;
		this.primitiveStride = primitiveStride;
		this.connectedPrimitives = connectedPrimitives;
	}

	public int indexCount(final int vertexCount) {
		return switch (this) {
			case LINES, QUADS -> vertexCount / 4 * 6;
			case DEBUG_LINES, DEBUG_LINE_STRIP, POINTS, TRIANGLES, TRIANGLE_STRIP, TRIANGLE_FAN -> vertexCount;
			default -> 0;
		};
	}
}