Hi,

I need to impose a specific texture on the triangle primitives.

So, I have a texture file: [attachment=13225:256colour3.png]

And I have a list of triangle primitives. I build a surface of these triangles. Each of triangle point contain data:

1) position

2) texture coordinate

Depands of texture coordinate on each point, I want to make color transition on the surface, like this:[attachment=13226:Capture1234.PNG]

But, using this shader

Texture ColorTexture;

sampler ColorTextureSampler = 
sampler_state 
{ 
texture = <ColorTexture> ; 
magfilter = NONE; 
minfilter = NONE; 
mipfilter = NONE; 
AddressU = wrap; 
AddressV = wrap; 
};

struct VertexShaderInput
{
    float4 Position : POSITION;
    float2 texCoord : TEXCOORD0;
};

struct VertexShaderOutput 
{
    float4 Position : POSITION;
    float2 texCoord : TEXCOORD0;
};

float4x4 worldViewProj;

VertexShaderOutput VertexShaderFunction(VertexShaderInput input)
{
	VertexShaderOutput output = (VertexShaderOutput)0;
	
	output.Position = mul(input.Position, worldViewProj);
	output.texCoord = input.texCoord;
	
    return output;
}

float4 PixelShaderFunction(VertexShaderOutput input) : COLOR
{	
	return tex1D( ColorTextureSampler, input.texCoord.x);
}

technique Technique1
{
    pass Pass1
    {
	VertexShader = compile vs_2_0 VertexShaderFunction();
        PixelShader = compile ps_2_0 PixelShaderFunction();
    }
}

I receive this: [attachment=13227:Capture1236.PNG]

So, how should I modificate shader to receive such kind of color transition? Or, maybe, I should modificate texture file?

Pixel Shader and Texture are fine, your UV coordinates are wrong though.

Unless the sampling of the UV coord can be modified in the Pixel Shader (or VS) using a formulae of some kind, I dont think it can be done.

how well is that plane subdivided?, the problem is that you can't get the output you want if your using 2 triangles per quad(and it looks like 9 quads), since the pixel shader linearly interpolates the uv values being passed in from the vertex's, this means you need to at least have the number of vertices equal to the number of data points, and then it has to be arranged to look like the quad, which could be very complex.

it might be better to actually take your pallete and build a 2D texture surface from your data points(and interpolate those data points yourself), then simply render that onto a quad.

edit: this might be possible in a compute or geometry shader though, but i don't believe you could achieve this easily with just vertex/pixel shader(although i'd love to see if someone does have a good solution).

You are right, here is 9 quads = 18 triangles = 16 points (data points). Each point has a texture coordinate. Number of vertices are equal to the number of data points since vertice IS a data point. Sorry, if I confused you. Each vertice contain coordinate and texture coordinate.

About 2D texture, not sure how it would help since my palette consists of vertical lines and V (y) coordinate is no needed (at the moment).

To my mind the problem is that textures are imposing on the separate element, not on all surface. But I may be wrong.

This is actually possible but you'd need a second texture, which would be a greyscale representation of the pattern you want. You do a standard tex2D lookup on that texture, then feed the result of that into your tex1D lookup to get the final colour.

Of course, by then you already have the pattern in a texture anyway so you may as well go all the way and put in the full RGB version, unless you have any specific reason not to (e.g. you want to swap out the RGB palette at runtime).

This is not the final surface, it can be changed. I need the universal solution, which can be implemented to any surface. As I understand, pattern will be sutable on for this surface. Changing of surface will require changing of pattern, or am I wrong?

I realy do not completely understand what should I do and it is my fault. I do not have enough knowledge and expirience for even understand all you are telling me. Sorry for that.

So, I modificated my shader for using 2 textures for lookup.

Texture ColorTexture;

sampler ColorTextureSampler = 
sampler_state 
{ 
texture = <ColorTexture> ; 
magfilter = NONE; 
minfilter = NONE; 
mipfilter = NONE; 
AddressU = wrap; 
AddressV = wrap; 
};

Texture AcrossTexture;

sampler AcrossTextureSampler = 
sampler_state 
{ 
texture = <AcrossTexture> ; 
magfilter = NONE; 
minfilter = NONE; 
mipfilter = NONE; 
AddressU = wrap; 
AddressV = wrap; 
};


struct VertexShaderInput
{
    float4 Position : POSITION;
    float2 texCoord : TEXCOORD0;
};

struct VertexShaderOutput 
{
    float4 Position : POSITION;
    float2 texCoord : TEXCOORD0;
};

float4x4 worldViewProj;

VertexShaderOutput VertexShaderFunction(VertexShaderInput input)
{
	VertexShaderOutput output = (VertexShaderOutput)0;
	
	output.Position = mul(input.Position, worldViewProj);
	output.texCoord = input.texCoord;
	
    return output;
}

float4 PixelShaderFunction(VertexShaderOutput input) : COLOR
{	
	float4 TextureColor = tex2D(AcrossTextureSampler, input.texCoord);	
	float f = TextureColor.r;
	return tex1D(ColorTextureSampler, f );
}

technique Technique1
{
    pass Pass1
    {
        VertexShader = compile vs_2_0 VertexShaderFunction();
        PixelShader = compile ps_2_0 PixelShaderFunction();
    }
}

Texture tex1 = Texture.FromFile(d3dDevice, "vertical.png");
Texture tex2 = Texture.FromFile(d3dDevice, "across.png");//, 100, 132, 1, Usage.None, Format.L8, Pool.Default, Filter.None, Filter.None, 1);  // L8 - grayscale format, but using this advanced options gives strange resylts  
            effect.SetTexture("ColorTexture", tex1);
            effect.SetTexture("AcrossTexture", tex2);

//vertices
for (int j = 0; j < list.Count; j++)
                {
                    points.Add(new Vertex()
                    {
                        Coord = new Vector2(0, SomeTextureCoordinate),
                        Position = new Vector3(list[j].X, list[j].Y, list[j].Z),
                    });
                }

AcrossTexture: [attachment=13240:across.png]

ColorTexture: [attachment=13241:256colour2.png]

Result: [attachment=13239:C.PNG]