[SOLVED]Bilboard shader for mesh based special effects

Arsakes said:

Since particle engine warband posses is rather limited i've come up with idea for "simulating"
particle effects via mesh vertex animations.
I need it for coding some cool spell efects i've made in blender, but those are using mesh based emitters and force fields for particle movement.

For example Blender allows for "exporting" particle system as animated mesh,  those could be imported to warband and with correct shader used as animated special effect.

However i need correct shader for that.
It seems that only change i have to make is to rewrite vertex shader part of "soft_particle_add" warband shader to render each triangle of model as facing to viewer.

Here is how am i doing that:

Spoiler

Code:

//////////////////////////////////////CUSTOM SHADER based on vs_dephed_flare///////////////////////////////////////////
VS_DEPTHED_FLARE vs_flare_custom(float4 vPosition : POSITION, float4 vColor : COLOR, float2 tc : TEXCOORD0)
{
	VS_DEPTHED_FLARE Out;

	 // apply world transformation to center of mesh (model-View)
	Out.Pos = mul(matWorldView, float4(0.0, 0.0, 0.0, 1.0) )  ;
        // we are in view space x-y are directions on the screen 
	Out.Pos.xy = vPosition.xy;

        // project
	Out.Pos = mul(matViewProj, Out.Pos);
   

	Out.Tex0 = tc;
	Out.Color = vColor * vMaterialColor;
	
	
	if(use_depth_effects) {
		Out.projCoord.xy = (float2(Out.Pos.x, -Out.Pos.y)+Out.Pos.w)/2;
		Out.projCoord.xy += (vDepthRT_HalfPixel_ViewportSizeInv.xy * Out.Pos.w);
		Out.projCoord.zw = Out.Pos.zw;
		Out.Depth = Out.Pos.z * far_clip_Inv;
	}

	//apply fog
	float3 P = mul(matWorldView, vPosition); //position in view space
	float4 vWorldPos = (float4)mul(matWorld,vPosition);
	float d = length(P);
	Out.Fog = get_fog_amount_new(d, vWorldPos.z);

	return Out;
}

....

// kompilacja shadera
VertexShader vs_particlelike_compiled = compile vs_2_0 vs_flare_custom();
technique particlelike_add
{
	pass P0
	{
		VertexShader = vs_particlelike_compiled;
		PixelShader = compile ps_2_0 ps_main_depthed_flare(false,true); // the same pixel shader as for soft_particle add shader
	}
}

As you can guess its not working.
The object is just invisible.
Could anybody check this shader?

The thing compiles and i've put resulting *.fxo everywhere

Regards,
Peter

Click to expand...

http://mbx.streetofeyes.com/index.php/topic,812.msg20380.html#msg20380

http://www.bytehazard.com/code/beam.html (Mirrored here: https://archive.today/EjdoX)
http://www.flipcode.com/archives/Billboarding-Excerpt_From_iReal-Time_Renderingi_2E.shtml

Arsakes said:

Hey,
could you provide some extra info regarding this beam-like particles (axial blilboarding) ?
This is precisely i need to do now. Is there any ready shader for this available?

Can I apply new shader to particle system just as "easy" as to props? Or there is some special warband **** that makes it impssible.

Click to expand...

http://www.bytehazard.com/articles/beam.html

http://archive.is/bFz8U

Arsakes said:

Hmm, so how did you do it in your starwars mod? The laser beams axis aligned particels?
I've seen the movies it seems you used such technique.

Click to expand...

Arsakes said:

Ok i've did the shader, didn't test it yet in MB though it work in ShaderMaker (the beam is oriented the best way possible as in this opengl tut).
Its in GLSL, will get you noticed after its teested in MB.

Thx.

I'm assuming that particle model is oriented along y direction (that is beam direction is in y in model coorinates), z is normal to bilboard mode.
Fragment shader is easy to write so I'm not showing it.

Code:

        
uniform mat4 viewMatrix;
uniform mat4 gl_ModelViewMatrix;
uniform mat4 gl_ProjectionMatrix;


const vec4 ex = vec4(1.0,0.0,0.0,0.0);
const vec4 ey = vec4(0.0,1.0,0.0,0.0);
const vec4 ez = vec4(0.0,0.0,1.0,0.0);

void main()
{

  // for rotation matrices this is inverse
  mat4 tvm = transpose(gl_ModelViewMatrix);
  vec3 up = gl_ModelViewMatrix[1].xyz; // ey na to przechodzi

  // question is what the direction in model space is transformed 
  // onto x-y view plane and is orthogonal to beam direction
  vec4 w = vec4(normalize(cross(ez.xyz, up.xyz)), 0.0);
  // cool now invert it to get direction in model space
  vec3 invW = (tvm*w).xyz;

  vec3 pos = gl_Vertex.x * invW + gl_Vertex.y * ey.xyz +          gl_Vertex.z*ez.xyz;

  gl_Position    = gl_ModelViewProjectionMatrix * vec4(pos, 1.0);
  gl_FrontColor  = gl_Color;
  gl_TexCoord[0] = gl_MultiTexCoord0;
}

Click to expand...

Arsakes said:

Hmm aren't rain particles axis aligned ones? Maybe the correct transformation is already there i've tested it getting strange results.
Did you test it?

Click to expand...

game_rain

psf_billboard_2d

game_snow

psf_billboard_3d

https://github.com/tldmod/tldmod/blob/master/ModuleSystem/module_particle_systems.py#L46

#psf_billboard_2d        = 0x0000000100 # up_vec = dir, front rotated towards camera
#psf_billboard_3d        = 0x0000000200 # front_vec point to camera.

Arsakes said:

I've DID IT! SHADER for axis aligned particle effects that works with scene props, missiles etc.
Welcome laser beams!!

Screeenies in spoiler!!

Spoiler

THanks man you've helped me.

Click to expand...