Switching to a vertex shader

Question

TL;DR I need to switch from a vertex array passed to the pixel shader with a real vertex shader approach.

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In my prototype, the terrain is procedurally generated and I have the following result:

The terrain vertices are passed directly to the pixel shader through an array:

//Number of vertices in terrain array
static const int verticesCount = 20;

//The vertices array, in pixel coordinates
float2 terrain[verticesCount];

//A fixed distance between neighbor vertices
float fixedDistance;

float4 PixelShaderFunction(float2 pixelCoords : VPOS,
                           float2 textureCoords :TEXCOORD0) : COLOR0
{
    float4 color = tex2D(s0, textureCoords);
    int i = pixelCoords.x / fixedDistance;
    float delta = (pixelCoords.x - terrain[i].x)/(terrain[i+1].x - terrain[i].x);
    if(smoothInterpolate(terrain[i].y, terrain[i+1].y, delta) >= pixelCoords.y)
    {
        color.rgba = 0;
    }
    return color;
}

As you can see I just interpolate between the vertices and mask the texture to the terrain.

Now I need a different approach because I'm using a view matrix for the camera and it does not affect these vertices that do not go through the vertex shader, how can I replace the terrain array with a vertex shader to get a similar result?

All suggestions are welcome!

Answer 1

Rendering it as a quad (two triangles) and passing the heights as an 1D texture, like a heithmap texture, can do the trick.