Another philosophical question (transform vs. using screen coordinates)

sosa · Mar 6th 2012, 8:07pm

What is better to use? for a 2D game? in general?

The Direct3D pipeline?
or
Drawing geometry directly using screen coordinates?

Any feedback is greatly appreciated!

Thank you!

Shanee · Mar 6th 2012, 8:14pm

Umm, I don't see how what you have described is different.

The DirectX sprite pipeline is just a pre-made way to render squares with a texture in 2D space on your screen.

Personally I use the sprite pipeline in DirectX but might move away from it, when making my engine use OpenGL ES 2.0 for the Android cross platforming I made my own sprite shader - which in fact does pretty much the same as the DirectX sprite pipeline does - except it allows a camera in a way I like more.

So it is a matter of preference I think. Also the sprite pipeline is pretty nicely optimized.

rezination · Mar 7th 2012, 3:55am

What are the specific techniques you are considering?

-Rez

sosa · Mar 7th 2012, 8:13am

Making a 2d adventure side scrolling platformer

sosa · Mar 7th 2012, 8:14am

sorry that didn't answer the question, techniques are I am learning and trying to use P and V shaders. can I use them in screen coordinates directly or do I need to use parts of the pipeline to leverage them?

Shanee · Mar 9th 2012, 3:36am

Let me ask you this way...

Screen coordinates pretty much means you are not transforming by world or camera or perspective, why would there be any difference for your pixel shaders or vertex shaders?

Also if you are using shaders then you have to use the geometry way and not the Sprite pipeline as far as I know (though I am unfamiliar with DX10 and DX11)

sosa · Mar 9th 2012, 10:50am

so if I understand you correctly, in order to use shaders i need geometry with textures. And for simple things without shaders like buttons I can use sprites.

In summary, anything that doesn't use shaders can be a sprites

Anything that does, must use geometry (quad of 2 triangles) to display it.

Do I need to use the transformations from object to world to screen to use shaders or can I use them with screen coordinates directly?

Shanee · Mar 9th 2012, 1:10pm

You can use screen coordinates. Do note that screen coordinates without a perspective matrix might be from -1 to 1 depending on DirectX version.

sosa · Mar 9th 2012, 4:33pm

Thanks, I will give it a try, just learning shaders so this will be good practice.

bad habit · Mar 10th 2012, 1:59pm

You might find these an interest:

gamedev.net/topic/525531-solved-c-id3dxsprite-and-hlsl/

create.msdn.com/en-US/educatio…log/sample/sprite_effects

sosa · Mar 11th 2012, 12:38pm

Thank you so much, this is great, I will read these ASAP.

Thanks again BH

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