GlStateManager.pushMatrix();
GlStateManager.translate(x + 0.5, y + 1.25, z + 0.5);
GlStateManager.rotate(180 - Minecraft.getMinecraft().getRenderManager().playerViewY, 0.0F, 1.0F, 0.0F);
GlStateManager.rotate(-Minecraft.getMinecraft().getRenderManager().playerViewX, 1.0F, 0.0F, 0.0F);
GlStateManager.scale(0.25, 0.25, 0.25);

GlStateManager.color(1, 1, 1, 1);
GlStateManager.disableTexture2D();
GlStateManager.disableAlpha();
GlStateManager.disableLighting();
GlStateManager.enableBlend();
GlStateManager.blendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);
GlStateManager.shadeModel(GL11.GL_SMOOTH);

WorldRenderer renderer = Tessellator.getInstance().getWorldRenderer();
renderer.begin(GL11.GL_TRIANGLE_FAN, DefaultVertexFormats.POSITION_COLOR);
renderer.pos(0, 0, 0).color(0, 1f, 0, 0f).endVertex();
double angle2 = Math.toRadians(180);
for (double theta = 0; theta <= angle2; theta += (2 * Math.PI / 360)) {
    renderer.pos(Math.cos(theta), Math.sin(theta), 0).color(0f, 1f, 0f, 1f).endVertex();
}
Tessellator.getInstance().draw();

GlStateManager.shadeModel(GL11.GL_FLAT);
GlStateManager.enableTexture2D();
GlStateManager.enableAlpha();
GlStateManager.enableLighting();
GlStateManager.disableBlend();
GlStateManager.popMatrix();