Currently my render can render an existing baked model for a block (for example Dirt) at a point in the world.  However, when I rotate the model (GlStateManager.rotate) it rotates relative to one of it's corners.  What I want to do is shift the origin from the corner to the center of the block so that when I do the rotations it will behave the way I want.

 

I am hoping for something easy.  I really don't want to dust off my old math texts to do some fancy math.  I am getting to old for that.

Can we please see the code you are using to render the baked model?

	public void renderParticle(VertexBuffer worldRendererIn, Entity entityIn, float partialTicks, float rotationX,
		float rotationZ, float rotationYZ, float rotationXY, float rotationXZ) {

	final float x = ((float) (this.prevPosX + (this.posX - this.prevPosX) * partialTicks - interpPosX));
	final float y = ((float) (this.prevPosY + (this.posY - this.prevPosY) * partialTicks - interpPosY));
	final float z = ((float) (this.prevPosZ + (this.posZ - this.prevPosZ) * partialTicks - interpPosZ));

	final float xRotation = MathStuff.wrapDegrees(this.xPeriod + this.xRotationRate * partialTicks);
	final float yRotation = MathStuff.wrapDegrees(this.yPeriod + this.yRotationRate * partialTicks);
	final float zRotation = MathStuff.wrapDegrees(this.zPeriod + this.zRotationRate * partialTicks);

	Minecraft.getMinecraft().renderEngine.bindTexture(TextureMap.LOCATION_BLOCKS_TEXTURE);

        GlStateManager.enableRescaleNormal();
	GlStateManager.pushMatrix();
	GlStateManager.pushAttrib();

	GlStateManager.translate(x, y, z);
	GlStateManager.scale(this.scale, this.scale, this.scale);

	GlStateManager.rotate(xRotation, 1.0F, 0, 0);
	GlStateManager.rotate(yRotation, 0, 1.0F, 0);
	GlStateManager.rotate(zRotation, 0, 0, 1.0F);
        
        final int i = this.getBrightnessForRender(partialTicks);
        final int j = i % 65536;
        final int k = i / 65536;
        OpenGlHelper.setLightmapTextureCoords(OpenGlHelper.lightmapTexUnit, (float)j, (float)k);
        GlStateManager.color(1.0F, 1.0F, 1.0F, 1.0F);
        final BlockRendererDispatcher blockrendererdispatcher = Minecraft.getMinecraft().getBlockRendererDispatcher();
        blockrendererdispatcher.renderBlockBrightness(this.state, 1.0F);
        
        GlStateManager.color(1, 1, 1, 1);
	GlStateManager.popAttrib();
	GlStateManager.popMatrix();
        GlStateManager.disableRescaleNormal();
}

 

This all works except the render "origin" of the block is one of it's corners.  I just want to convince the model that it's actually been shifted so instead of rendering along an axis "0..10" it's something like "-5..5".

translate(-0.5,-0.5,-0.5)

rotate(x,y,z,w)

translate(0.5,0.5,0.5)

*Picks himself off the floor - blinks*

 

OK.  Got that working.  What I think happened is that I tried something similar to this but one of the values for the translation was off.  Maybe I need to stop writing code at such late hours of the evening.

 

For posterity here is the updated code:

 

	public void renderParticle(VertexBuffer worldRendererIn, Entity entityIn, float partialTicks, float rotationX,
		float rotationZ, float rotationYZ, float rotationXY, float rotationXZ) {

	final float x = ((float) (this.prevPosX + (this.posX - this.prevPosX) * partialTicks - interpPosX));
	final float y = ((float) (this.prevPosY + (this.posY - this.prevPosY) * partialTicks - interpPosY));
	final float z = ((float) (this.prevPosZ + (this.posZ - this.prevPosZ) * partialTicks - interpPosZ));

	final float pitch = MathStuff.wrapDegrees(this.currentPitch + this.pitchRate * partialTicks);
	final float yaw = MathStuff.wrapDegrees(this.currentYaw + this.yawRate * partialTicks);
	final float roll = MathStuff.wrapDegrees(this.currentRoll + this.rollRate * partialTicks);

	Minecraft.getMinecraft().renderEngine.bindTexture(TextureMap.LOCATION_BLOCKS_TEXTURE);

	GlStateManager.enableRescaleNormal();
	GlStateManager.pushMatrix();
	GlStateManager.pushAttrib();

	GlStateManager.translate(x, y, z);
	GlStateManager.scale(this.scale, this.scale, this.scale);

	GlStateManager.rotate(roll, 0, 0, 1.0F);
	GlStateManager.rotate(pitch, 1.0F, 0, 0);
	GlStateManager.rotate(yaw, 0, 1.0F, 0);
	GlStateManager.translate(-0.5F, -0.5F, 0.5F);

	final int i = this.getBrightnessForRender(partialTicks);
	final int j = i % 65536;
	final int k = i / 65536;
	OpenGlHelper.setLightmapTextureCoords(OpenGlHelper.lightmapTexUnit, (float) j, (float) k);

	GlStateManager.color(1.0F, 1.0F, 1.0F, 1.0F);
	final BlockRendererDispatcher blockrendererdispatcher = Minecraft.getMinecraft().getBlockRendererDispatcher();
	blockrendererdispatcher.renderBlockBrightness(this.state, 1.0F);

	GlStateManager.color(1, 1, 1, 1);
	GlStateManager.popAttrib();
	GlStateManager.popMatrix();
	GlStateManager.disableRescaleNormal();
}