Shaders Causing Headaches - GameCreators Forum

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Hicksyfern

15

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Joined: 10th Jul 2009

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Posted: 10th Jul 2009 17:17

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Hi,

I've looked around the forums for how to sort this and it's driving me bananas.

I'm trying to learn how to use shaders with very little success. I have created a shader with the following code, to just draw me a red object when I load the shader:

+ Code Snippet

matrix wvp : WorldViewProjection;

struct VS_INPUT
{
	float4 Pos	:POSITION;
};

struct VS_OUTPUT
{
	float4 Pos	:POSITION;
};

struct PS_INPUT
{
	float4 Col	:COLOR;
};

VS_OUTPUT vs(VS_INPUT i) {
	VS_OUTPUT o;
	o.Pos = mul( i.Pos, wvp);
	return o;
};

PS_INPUT ps(VS_OUT IN): COLOR
{
	PS_INPUT colour;
	colour = float4(1.0, 0.0, 0.0, 1.0);
	return colour;
};

technique SimpleShader
{
	pass p0
	{
		VertexShader = compile vs_1_1	vs();
		PixelShader = compile ps_1_1 ps();
	}
};

Then I'm doing a simple:

dbMakeObjectSphere(1, 20);
dbLoadEffect("simple.fx", 1, 0);
dbSetObjectEffect(1, 1);

and my sphere disappears.

Is there anything else I need to set up to make my shaders work? I've tried downloading the "test compatability" shader by Green Gandalf and the same - my obhect simply doesn't draw.

What can I do to fix this?

Cheers,

Tom

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jezza

16

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Joined: 8th Mar 2008

Location: Bham, UK

Posted: 11th Jul 2009 11:14

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Are you using shader debugging?
Go to All Programs>DirectX SDK>DirectX Utilities>DirectX Control Panel
then check "enable shader debugging"
I don't know much about how shaders have to be set up for GDK, but you should replace this line:
colour = float4(1.0, 0.0, 0.0, 1.0);
with this
colour.Col = float4(1.0, 0.0, 0.0, 1.0);
And you've put
PS_INPUT ps(VS_OUT IN): COLOR
but the semantic is handled by the struct, so you just need
PS_INPUT ps(VS_OUT IN)

Actually, the whole struct is unnecessary because the only thing a pixel shader can output is one float4, so you just put:

+ Code Snippet

float4 ps(VS_OUT IN): COLOR
{
	float4 colour = float4(1.0, 0.0, 0.0, 1.0);
	return colour;
};

p.s. you spelt colour with a u

I always do that, I bet it will annoy 'mericans when i get into professional programming.

While Bored Blog

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Morcilla

21

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Joined: 1st Dec 2002

Location: Spain

Posted: 11th Jul 2009 12:18

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Apart from jezza's suggestions, I think it is mandatory to compile in shader model 2.0 (as minimum). Try to change this:

+ Code Snippet

technique SimpleShader
{
	pass p0
	{
		VertexShader = compile vs_1_1	vs();
		PixelShader = compile ps_1_1 ps();
	}
};

To this:

+ Code Snippet

technique SimpleShader
{
	pass p0
	{
		VertexShader = compile vs_2_0	vs();
		PixelShader = compile ps_2_0 ps();
	}
};

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jezza

16

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Joined: 8th Mar 2008

Location: Bham, UK

Posted: 11th Jul 2009 13:54

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Noitced your declaration of mvp. When using 'matrix' you have to put datatype and size, like this:
matrix <float, 4, 4> mvp : WorldViewProjection;
so it would be better just to use
float4x4 mvp : WorldViewProjection;

While Bored Blog

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KirDael

15

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Joined: 22nd Jan 2009

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Posted: 27th Jul 2009 20:27

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your shader contains errors... wait i fix them ;P´

There are many things you don't need

+ Code Snippet

matrix wvp : WorldViewProjection;

struct VS_OUTPUT
{
	float4 Pos	:POSITION;
};

struct PS_INPUT
{
	float4 Col	:COLOR;
};

VS_OUTPUT vs(PS_INPUT i) {
	VS_OUTPUT o;
	o.Pos = mul( i.Pos, wvp);
	return o;
};

float4 ps(VS_OUTPUT IN): COLOR
{
	return float4(1.0, 0.0, 0.0, 1.0);
};

technique SimpleShader
{
	pass p0
	{
		VertexShader = compile vs_1_1	vs();
		PixelShader = compile ps_1_1 ps();
	}
};

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KirDael

15

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Joined: 22nd Jan 2009

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Posted: 27th Jul 2009 20:29

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Sorry !!!! this one has no errors xD

+ Code Snippet

matrix wvp : WorldViewProjection;

struct VS_OUTPUT
{
	float4 Pos	:POSITION;
};

struct PS_INPUT
{
	float4 Pos	:POSITION;
};

VS_OUTPUT vs(PS_INPUT i) {
	VS_OUTPUT o;
	o.Pos = mul( i.Pos, wvp);
	return o;
};

float4 ps(VS_OUTPUT IN): COLOR
{
	return float4(1.0, 0.0, 0.0, 1.0);
};

technique SimpleShader
{
	pass p0
	{
		VertexShader = compile vs_1_1	vs();
		PixelShader = compile ps_1_1 ps();
	}
};

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dark coder

22

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Joined: 6th Oct 2002

Location: Japan

Posted: 27th Jul 2009 20:34

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Morcilla already pointed out the major issue with the shader, and other than his 'colour = float4(1.0, 0.0, 0.0, 1.0);' (colour is a struct) his code looks fine. Yours may be shorter but it doesn't really make much sense when reading it, why use the PS_INPUT as the VS input? Plus you still didn't fix the pixel shader model issue.

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KirDael

15

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Joined: 22nd Jan 2009

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Posted: 9th Aug 2009 20:33

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i dont understand you

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Amnzero

15

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Joined: 1st Aug 2009

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Posted: 9th Aug 2009 22:24

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Join the club KirDael...

if(enemy == Amnzero) runAway();
Amnzero->WebSite = L"http://neovance.com/";

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KirDael

15

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Joined: 22nd Jan 2009

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Posted: 10th Aug 2009 11:56

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well, my shader is working... but there could also be some mistakes because i wrote it down quickly...

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