i try to programm a texture projection shader in HLSL.. it works but
the projected picture must be smaller in the near than in the far distance like a flashlight.

Joey told me that i need a perspective projection matrix. but i dont know how to solve this problem.

screenshot:


demo:
Texture Projection Shader.exe

my shader:
Code:

---

//--------------------------------------------------------------
//		Texture Projection Shader HLSL
//
//			© by zSteam
//
//		date: 19.10.2007
// -------------------------------------------------------------

float4x4 matWorldViewProj;
float4x4 matMtl;

struct VS_OUTPUT
{
	float4 Pos	: POSITION;
	float2 texCoord : TEXCOORD0;
	float3 lightVec : TEXCOORD1;
};

VS_OUTPUT mainVS( float4 Pos : POSITION, float2 texCoord : TEXCOORD0 )
{
	VS_OUTPUT Out = (VS_OUTPUT) 0; 

	Out.Pos = mul(Pos, matWorldViewProj);

	float2 tps = (mul(Pos, matMtl) * 0.005f) + 0.5f; // ? und korrektur der position des projizierten bildes

	Out.texCoord = tps;
	Out.lightVec.xy = texCoord.xy;

	return Out;
}

texture entSkin1;
texture mtlSkin1;

sampler BaseTex = sampler_state
{
	Texture = <entSkin1>;
	MinFilter = Linear;
	MagFilter = Linear;
	MipFilter = Linear;
	AddressU  = wrap;
	AddressV  = wrap;
};

sampler ProjTex = sampler_state
{
	Texture = <mtlSkin1>;
	MinFilter = Linear;
	MagFilter = Linear;
	MipFilter = Linear;
	AddressU  = clamp;
	AddressV  = clamp;
};

float4 mainPS(float2 texCoord : TEXCOORD0, float2 lightVec : TEXCOORD1 ) : COLOR
{
	float4 base = tex2D( BaseTex, lightVec );
	float4 proj = tex2D( ProjTex, texCoord ) * 4;

	return (base + 0.1 * proj);
}

technique projector
{
	pass p1
	{
		VertexShader = compile vs_1_1 mainVS();
		PixelShader = compile ps_1_1 mainPS();
	}
}

technique fallback { pass one { } }

---

You need to alter the way your matMtl is setup. Try searching for "perspective projection matrix" in google, and use that to construct your matrix. Or put a view at the projector position, and get it's matView and copy that to your matMtl before rendering.

hi .. sry but i don't understand what you mean .... what must i change

my script for the shader:
Code:

---

bmap projectiontex = <Spotlight.jpg>;

var scan_radius=1000; 
var lighttimer=0; 
var matTexProj[16];
var tempmatrix[16];
var WorldToProjection[16];
var matClipProj[16];

entity* beamer;

var d3d_automaterial = 1;

function mat_projection_init()
{
	//set up the texture projection matrix	
	matTexProj[0]=my.skill80;
	matTexProj[1]=my.skill81;
	matTexProj[2]=my.skill82;
	matTexProj[3]=my.skill83;

	matTexProj[4]=my.skill84;
	matTexProj[5]=my.skill85;
	matTexProj[6]=my.skill86;
	matTexProj[7]=my.skill87;

	matTexProj[8]=my.skill88;
	matTexProj[9]=my.skill89;
	matTexProj[10]=my.skill90;
	matTexProj[11]=my.skill91;

	matTexProj[12]=my.skill92;
	matTexProj[13]=my.skill93;
	matTexProj[14]=my.skill94;
	matTexProj[15]=my.skill95;

	mat_set(mtl.matrix,matWorld);
	mat_multiply(mtl.matrix,matTexProj);

/*
	mat_set(mtl.matrix,matView);
	mat_multiply(mtl.matrix,matProj);

	mat_inverse(mtl.matrix, mtl.matrix);
	mat_transpose(mtl.matrix, mtl.matrix);
*/
}


material mat_projection
{
	skin1 = projectiontex;

	event = mat_projection_init; 

	flags = tangent | enable_render | translucent;
	//effect = "tproj_asm.fx";
	effect = "tproj_hlsl.fx";
}

function mat_projection_init_test()
{
	if(!beamer){wait(1);}

	//set up the texture projection matrix	
	matTexProj[0]=beamer.skill80;
	matTexProj[1]=beamer.skill81;
	matTexProj[2]=beamer.skill82;
	matTexProj[3]=beamer.skill83;

	matTexProj[4]=beamer.skill84;
	matTexProj[5]=beamer.skill85;
	matTexProj[6]=beamer.skill86;
	matTexProj[7]=beamer.skill87;

	matTexProj[8]=beamer.skill88;
	matTexProj[9]=beamer.skill89;
	matTexProj[10]=beamer.skill90;
	matTexProj[11]=beamer.skill91;

	matTexProj[12]=beamer.skill92;
	matTexProj[13]=beamer.skill93;
	matTexProj[14]=beamer.skill94;
	matTexProj[15]=beamer.skill95;

	mat_set(mtl.matrix,matWorld);
	mat_multiply(mtl.matrix,matTexProj);

/*
	mat_set(mtl.matrix,matView);
	mat_multiply(mtl.matrix,matProj);

	mat_inverse(mtl.matrix, mtl.matrix);
	mat_transpose(mtl.matrix, mtl.matrix);
*/

}
/*
material rockywall
{
	skin1 = projectiontex;

	event = mat_projection_init_test; 

	flags = tangent | enable_render | translucent;
	//effect = "tproj_asm.fx";
	effect = "tproj_hlsl.fx";
}
*/
function light_data()
{
	if event_type==event_detect && my.skill4 == 6666 //projector
	{
		your.material=mat_projection;

		//texture projection matrix
		you.skill80=my.skill80; 
		you.skill81=my.skill81;
		you.skill82=my.skill82;
		you.skill83=my.skill83;

		you.skill84=my.skill84;
		you.skill85=my.skill85;
		you.skill86=my.skill86;
		you.skill87=my.skill87;

		you.skill88=my.skill88;
		you.skill89=my.skill89;
		you.skill90=my.skill90;
		you.skill91=my.skill91;

		you.skill92=my.skill92;
		you.skill93=my.skill93;
		you.skill94=my.skill94;
		you.skill95=my.skill95;
	}	
}

function light_view_matrix()
{
	//temporary matrix to store view matrix
	//vec_set(proj_view.x,my.x);
	//vec_set(proj_view.pan,my.pan);

	wait(1);

	mat_set(tempmatrix,matView);

	my.skill80=tempmatrix[0];
	my.skill81=tempmatrix[1];
	my.skill82=tempmatrix[2];
	my.skill83=tempmatrix[3];

	my.skill84=tempmatrix[4];
	my.skill85=tempmatrix[5];
	my.skill86=tempmatrix[6];
	my.skill87=tempmatrix[7];

	my.skill88=tempmatrix[8];
	my.skill89=tempmatrix[9];
	my.skill90=tempmatrix[10];
	my.skill91=tempmatrix[11];

	my.skill92=tempmatrix[12];
	my.skill93=tempmatrix[13];
	my.skill94=tempmatrix[14];
	my.skill95=tempmatrix[15];

}

ACTION lightobject
{
	beamer=me;
	MY.passable=ON;
	my.invisible=off;
	my.enable_detect=on;
	my.event=light_data;

	my.skill100=lighttimer;
	lighttimer+=1;

	if my.skill4==6666 //is a projector
	{
		//light_view_matrix();

		wait(my.skill100);

		while(1)
		{
			temp.pan = 360;
			temp.tilt = 360;
			temp.z = scan_radius;	
			//indicator=NULL;
			scan_entity(my.x,temp);

			light_view_matrix();

			//vec_set(my.x,camera.x);
			//vec_set(my.pan,camera.pan);
			my.pan+=5*time;

			wait(1);
		}
	}
}

action leinenwand
{
	my.enable_scan=on;
}

---

Oh I see now, the matrix is correct but you forgot the perspective divide.

Try this:
struct VS_OUTPUT
{
float4 Pos : POSITION;
float4 texCoord : TEXCOORD0; // float 4
float3 lightVec : TEXCOORD1;
};


float4 tps = (mul(Pos, matMtl) * 0.005f) + 0.5f; // tps is float4 too.
tps.xyz /= tps.w;

hi Thanks .. but this doesn't work and it's tilted :/

Ok keep the float4s, remove the division and change the tex2D to tex2Dproj. I'm just trying some things here, it's been a very long time since I've programmed shaders.

ok thx i looks better but not real ... i think i need the z-axis (near/far clip)...

Did you have any further progress with this shader which could be worth to be shared (in case you don´t care about sharing)?

In case you´ve got it done without any problems, it would be awsome if you could add it to the 3DGS wiki or post it here, so that I could add it.

Thank you,
Slin