Program: 63593
Project: 63593
Buggy source:
private void render(TemperatureState state,float progress,EnumFacing orientation,double x,double y,double z){
  GlStateManager.pushMatrix();
  GlStateManager.pushAttrib();
  GlStateManager.enableLighting();
  GlStateManager.disableBlend();
  GlStateManager.enableCull();
  GlStateManager.color(1,1,1);
  GlStateManager.translate((float)x,(float)y,(float)z);
  float step;
  if (progress > 0.5) {
    step=5.99F - (progress - 0.5F) * 2F * 5.99F;
  }
 else {
    step=progress * 2F * 5.99F;
  }
  float tfactor=step / 16;
  float[] angle={0,0,0};
  float[] translate={orientation.getFrontOffsetX(),orientation.getFrontOffsetY(),orientation.getFrontOffsetZ()};
switch (orientation) {
case EAST:
case WEST:
case DOWN:
    angle[2]=angleMap[orientation.ordinal()];
  break;
case SOUTH:
case NORTH:
default :
angle[0]=angleMap[orientation.ordinal()];
break;
}
boiler.rotateAngleX=angle[0];
boiler.rotateAngleY=angle[1];
boiler.rotateAngleZ=angle[2];
trunk.rotateAngleX=angle[0];
trunk.rotateAngleY=angle[1];
trunk.rotateAngleZ=angle[2];
piston.rotateAngleX=angle[0];
piston.rotateAngleY=angle[1];
piston.rotateAngleZ=angle[2];
extension.rotateAngleX=angle[0];
extension.rotateAngleY=angle[1];
extension.rotateAngleZ=angle[2];
float factor=(float)(1.0 / 16.0);
Proxies.render.bindTexture(textures[Textures.BASE.ordinal()]);
boiler.render(factor);
Proxies.render.bindTexture(textures[Textures.PISTON.ordinal()]);
GlStateManager.translate(translate[0] * tfactor,translate[1] * tfactor,translate[2] * tfactor);
piston.render(factor);
GlStateManager.translate(-translate[0] * tfactor,-translate[1] * tfactor,-translate[2] * tfactor);
ResourceLocation texture;
switch (state) {
case OVERHEATING:
texture=textures[Textures.TRUNK_HIGHEST.ordinal()];
break;
case RUNNING_HOT:
texture=textures[Textures.TRUNK_HIGHER.ordinal()];
break;
case OPERATING_TEMPERATURE:
texture=textures[Textures.TRUNK_HIGH.ordinal()];
break;
case WARMED_UP:
texture=textures[Textures.TRUNK_MEDIUM.ordinal()];
break;
case COOL:
default :
texture=textures[Textures.TRUNK_LOW.ordinal()];
break;
}
Proxies.render.bindTexture(texture);
trunk.render(factor);
Proxies.render.bindTexture(textures[Textures.EXTENSION.ordinal()]);
float chamberf=2F / 16F;
if (step > 0) {
for (int i=0; i <= step + 2; i+=2) {
extension.render(factor);
GlStateManager.translate(translate[0] * chamberf,translate[1] * chamberf,translate[2] * chamberf);
}
}
GlStateManager.popAttrib();
GlStateManager.popMatrix();
}

Fixed version (ground truth):
private void render(TemperatureState state,float progress,EnumFacing orientation,double x,double y,double z){
  GlStateManager.color(1,1,1);
  GlStateManager.pushMatrix();
  GlStateManager.translate((float)x,(float)y,(float)z);
  float step;
  if (progress > 0.5) {
    step=5.99F - (progress - 0.5F) * 2F * 5.99F;
  }
 else {
    step=progress * 2F * 5.99F;
  }
  float tfactor=step / 16;
  float[] angle={0,0,0};
  float[] translate={orientation.getFrontOffsetX(),orientation.getFrontOffsetY(),orientation.getFrontOffsetZ()};
switch (orientation) {
case EAST:
case WEST:
case DOWN:
    angle[2]=angleMap[orientation.ordinal()];
  break;
case SOUTH:
case NORTH:
default :
angle[0]=angleMap[orientation.ordinal()];
break;
}
boiler.rotateAngleX=angle[0];
boiler.rotateAngleY=angle[1];
boiler.rotateAngleZ=angle[2];
trunk.rotateAngleX=angle[0];
trunk.rotateAngleY=angle[1];
trunk.rotateAngleZ=angle[2];
piston.rotateAngleX=angle[0];
piston.rotateAngleY=angle[1];
piston.rotateAngleZ=angle[2];
extension.rotateAngleX=angle[0];
extension.rotateAngleY=angle[1];
extension.rotateAngleZ=angle[2];
float factor=(float)(1.0 / 16.0);
Proxies.render.bindTexture(textures[Textures.BASE.ordinal()]);
boiler.render(factor);
Proxies.render.bindTexture(textures[Textures.PISTON.ordinal()]);
GlStateManager.translate(translate[0] * tfactor,translate[1] * tfactor,translate[2] * tfactor);
piston.render(factor);
GlStateManager.translate(-translate[0] * tfactor,-translate[1] * tfactor,-translate[2] * tfactor);
ResourceLocation texture;
switch (state) {
case OVERHEATING:
texture=textures[Textures.TRUNK_HIGHEST.ordinal()];
break;
case RUNNING_HOT:
texture=textures[Textures.TRUNK_HIGHER.ordinal()];
break;
case OPERATING_TEMPERATURE:
texture=textures[Textures.TRUNK_HIGH.ordinal()];
break;
case WARMED_UP:
texture=textures[Textures.TRUNK_MEDIUM.ordinal()];
break;
case COOL:
default :
texture=textures[Textures.TRUNK_LOW.ordinal()];
break;
}
Proxies.render.bindTexture(texture);
trunk.render(factor);
Proxies.render.bindTexture(textures[Textures.EXTENSION.ordinal()]);
float chamberf=2F / 16F;
if (step > 0) {
for (int i=0; i <= step + 2; i+=2) {
extension.render(factor);
GlStateManager.translate(translate[0] * chamberf,translate[1] * chamberf,translate[2] * chamberf);
}
}
GlStateManager.popMatrix();
}