RenderHelper

public static void drawTextureCustomSize(double posX, double posY, double startPixX, double startPixY, double pieceSizeX, double pieceSizeY, float sizeTextureX, float sizeTextureY)
    {
        float f4 = 1.0F / sizeTextureX;
        float f5 = 1.0F / sizeTextureY;
        Tessellator tessellator = Tessellator.instance;
        tessellator.startDrawingQuads();
        tessellator.addVertexWithUV((double)posX, (double)(posY + pieceSizeY), 0.0D, (double)(startPixX * f4), (double)((startPixY + (float)pieceSizeY) * f5));
        tessellator.addVertexWithUV((double)(posX + pieceSizeX), (double)(posY + pieceSizeY), 0.0D, (double)((startPixX + (float)pieceSizeX) * f4), (double)((startPixY + (float)pieceSizeY) * f5));
        tessellator.addVertexWithUV((double)(posX + pieceSizeX), (double)posY, 0.0D, (double)((startPixX + (float)pieceSizeX) * f4), (double)(startPixY * f5));
        tessellator.addVertexWithUV((double)posX, (double)posY, 0.0D, (double)(startPixX * f4), (double)(startPixY * f5));
        tessellator.draw();
    }