Rendering of the destroy stages - Alpha from grayscale

[Bedrock_Miner]

Hey Guys!

I wanted to render some textures with the same technique the destroy overlay is rendered:

The grayscale of the texture is calculated into a corresponding alpha value. But actually I don't understand how this is done. I looked in RenderGlobal, tried to understand the code, copied something, no effect..

Can anybody explain how to do this?

[Bedrock_Miner]

Anyone?? Pls..

[TheGreyGhost]

Hi

 

I'm not sure what effect you're talking about - do you mean the cracks?

RenderGlobal::

public void drawBlockDamageTexture(Tessellator par1Tessellator, EntityLivingBase par2EntityPlayer, float par3)

or the flying fragments when the block bursts?

EntityDiggingFX

 

-TGG

[Bedrock_Miner]

Actually I'm not trying to render the cracks but another texture. But i want to do it the same way as the cracks are rendered: grayscale to alpha

[TheGreyGhost]

The blending is done using the source and destination colour instead of alpha information, due to this command

 

            GL11.glBlendFunc(GL11.GL_DST_COLOR, GL11.GL_SRC_COLOR);

 

This makes the blending use the source colour and destination colour, instead of the more usual alpha blending

            GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);

 

You may also need GL11.glEnable(GL11.GL_BLEND); before the rendering.  These bits are also important to make the cracks stand a bit proud of the block surface

 

            GL11.glDisable(GL11.GL_ALPHA_TEST);
            GL11.glPolygonOffset(-3.0F, -3.0F);
            GL11.glEnable(GL11.GL_POLYGON_OFFSET_FILL);
            GL11.glEnable(GL11.GL_ALPHA_TEST);

 

See this link for more information...

 

http://www.glprogramming.com/red/chapter06.html

 

-TGG