Hot to create a colored triangle?

BlitzMax Forums/BlitzMax Programming/Hot to create a colored triangle?

MrCredo

(Posted 2007) [#1]

I know DrawPoly command - but how to color each corner of this polygon?

I mean this is doable in OpenGl/DirectX (but if i can use this directly - i do not need blitzmax). But why is this not done in blitzmax? I think this should added to next update.

tonyg

(Posted 2007) [#2]

Are you asking 'how to' do it, whether Bmax already does it or whether we think it should do it?
If I wanted to set each vertex colour I would use the TD3D7Max2DDriver 'Setcolor' method as a template. The drawframe method would also be helpful.
Not sure whether this helps as I'm not sure what you want to do.

ImaginaryHuman

(Posted 2007) [#3]

He wants a different color for each corner of the triangle and to have it smooth/gauraud shaded. You cannot do this in Max without writing your own triangle code in GL or DX.

TartanTangerine (was Indiepath)

(Posted 2007) [#4]

You can use my Textured Poly module and pass a NULL image. You have full access to the Vertex Color, Alpha and Normals. The full source is there so you might just want to pick the bits you need.

http://www.modules.indiepath.com

Psilo

(Posted 2007) [#5]

that Textured Poly is usefull, thanks

MrCredo

(Posted 2007) [#6]

I think this is useful and should included to blitzmax...

MrCredo

(Posted 2007) [#7]

I readed BlitzMax-Sources... I wish i never seen this:

	Method DrawPoly( xy#[],handlex#,handley#,tx#,ty# )
		If xy.length<6 Or (xy.length&1) Return
		Local segs=xy.length/2
		Local vrts#[]=New Float[segs*4]		
		Local c:Int Ptr=Int Ptr(Float Ptr(vrts))
		For Local i=0 Until Len xy Step 2
			Local x#=xy[i+0]+handlex
			Local y#=xy[i+1]+handley
			vrts[i*2+0]=x*ix+y*iy+tx
			vrts[i*2+1]=x*jx+y*jy+ty
			c[i*2+3]=drawcolor			
		Next
		If SetActiveFrame(Null)
			device.DrawPrimitive(D3DPT_TRIANGLEFAN,D3DFVF_XYZ|D3DFVF_DIFFUSE,vrts,segs,0)		
		EndIf
	End Method

This code create Float-Data (but 2x more than needed). Why? Part of this is not directly used, but one part is used for color. But colors are integers, so that a float-pointer is converted to integer-pointer - and then a integer value is assigned to "Float-Data". Crazy.

Mr. Write Errors Man

(Posted 2007) [#8]

Indiepath,

I downloaded texturedpoly.mod and I noticed that line 193:

PrimaryDevice.device.DrawPrimitive(RenderType,D3DFVF_XYZ|D3DFVF_NORMAL|D3DFVF_DIFFUSE|D3DFVF_TEX1,xyuv,segs,0)

needs to be changed to this:

D3D7GraphicsDriver().Direct3DDevice7().DrawPrimitive(RenderType,D3DFVF_XYZ|D3DFVF_NORMAL|D3DFVF_DIFFUSE|D3DFVF_TEX1,xyuv,segs,0)

Otherwise module won't compile.

-AF

xMicky

(Posted 2007) [#9]

@MrCredo: Have you tried to simplify the code you don't like and does it work ? I think there may be a reason for the *ugly* code in the data structure directX expects, but I have no deeper knowledge of handling the beast DirectX.

Sokurah

(Posted 2007) [#10]

Thanks Artic...I was screwing around with that mod and couldn't make it work.
This was exactly what I needed. :-)