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emulti

Drawing squares in DirectX 8

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Complete beginner here. I have been able to create triangles using vertices and would now like to move on to creating squares and apply a texture to it to display a 2d image. So far I have a transformed lit vertex to work with and attempting to use DrawPrimitive with this to display a square. The image I get is a triangle, not surprisingly, with two sides using two of the vertices in the square I have described. The other sides go off to the second vertex of a triangle I had already drawn next to it. So questions: 1. Should I be using DrawPrimitive or DrawPrimitiveUP? 2. Should I specifying more triangles to be drawn? 3. Does it sound like I have my square vertices in the wrong order? 4. Is there a common method for drawing squares from vertices? Any advice on this would be much appreciated.

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a square = two triangles

You can always make a class to make it simpler, though. Although I am a relatively new to directX, I know that you cannot render a square per say. You need to render 2 triangles.

-Unsuspected

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This is certainly true.

I have just realized that I am a simpleton. I rechecked my y co-ordinates and they were out by 200 pixels. I now have a white square where there was just a black void before.

I am using DrawPrimitive with D3DPT_TRIANGLEFAN and 4 for PrimitiveCount. Can anybody tell me why TRIANGLEFAN only gives me the original triangle and one mirror image. I read in the help that it should fan mirror images on all sides of the original triangle. Perhaps I have mis-understood this. I guess I would have to supply more vertices to get this effect. But a square is good enough for me right now.

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Just found out I only need 2 for PrimitiveCount because I am only drawing two triangles with TRIANGLEFAN.

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There are much more effective ways to draw a cube w/o using triangle fan.
I suggest "The Zen of Direct3D Game Programming."
It does a great job explaining DirectX and 3D programming!

-Unsuspected

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