Code:
protected void drawSideGradientRect(int i, int j, int k, int l, int i1, int j1)
{
float f = (float)(i1 >> 24 & 0xff) / 255F;
float f1 = (float)(i1 >> 16 & 0xff) / 255F;
float f2 = (float)(i1 >> 8 & 0xff) / 255F;
float f3 = (float)(i1 & 0xff) / 255F;
float f4 = (float)(j1 >> 24 & 0xff) / 255F;
float f5 = (float)(j1 >> 16 & 0xff) / 255F;
float f6 = (float)(j1 >> 8 & 0xff) / 255F;
float f7 = (float)(j1 & 0xff) / 255F;
GL11.glDisable(3553 /*GL_TEXTURE_2D*/);
GL11.glEnable(3042 /*GL_BLEND*/);
GL11.glDisable(3008 /*GL_ALPHA_TEST*/);
GL11.glBlendFunc(770, 771);
GL11.glShadeModel(7425 /*GL_SMOOTH*/);
Tessellator tessellator = Tessellator.instance;
tessellator.startDrawingQuads();
tessellator.setColorRGBA_F(f1, f2, f3, f);
tessellator.addVertex(k, j, zLevel);
tessellator.setColorRGBA_F(f5, f6, f7, f4);
tessellator.addVertex(i, j, zLevel);
tessellator.addVertex(i, l, zLevel);
tessellator.setColorRGBA_F(f1, f2, f3, f);
tessellator.addVertex(k, l, zLevel);
tessellator.draw();
GL11.glShadeModel(7424 /*GL_FLAT*/);
GL11.glDisable(3042 /*GL_BLEND*/);
GL11.glEnable(3008 /*GL_ALPHA_TEST*/);
GL11.glEnable(3553 /*GL_TEXTURE_2D*/);
}