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6c80390de7
The `Sample` method has an offset parameter which we can use here. The result is not identical to the old shader, as the older shader used the height of the terminal for drawing horizontal edges and so the result looked way fatter than it was seemingly originally intended. On my 150% scale display I found an offset of +/- 2px to produce an acceptable result, although in the future it might be worthwhile to make the offset dependent on the UI scale. Closes #14953
48 lines
1.7 KiB
HLSL
48 lines
1.7 KiB
HLSL
// A minimal pixel shader that outlines text
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// The terminal graphics as a texture
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Texture2D shaderTexture;
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SamplerState samplerState;
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// Terminal settings such as the resolution of the texture
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cbuffer PixelShaderSettings {
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// The number of seconds since the pixel shader was enabled
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float Time;
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// UI Scale
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float Scale;
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// Resolution of the shaderTexture
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float2 Resolution;
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// Background color as rgba
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float4 Background;
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};
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// A pixel shader is a program that given a texture coordinate (tex) produces a color.
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// tex is an x,y tuple that ranges from 0,0 (top left) to 1,1 (bottom right).
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// Just ignore the pos parameter.
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float4 main(float4 pos : SV_POSITION, float2 tex : TEXCOORD) : SV_TARGET
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{
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// Read the color value at the current texture coordinate (tex)
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// float4 is tuple of 4 floats, rgba
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float4 color = shaderTexture.Sample(samplerState, tex);
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// Read the color value at some offset, will be used as shadow. For the best
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// effect, read the colors offset on the left, right, top, bottom of this
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// fragment, as well as on the corners of this fragment.
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//
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// Now, if any of those adjacent cells has text in it, then the *color vec4
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// will have a non-zero .w (which is used for alpha). Use that alpha value
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// to add some black to the current fragment.
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//
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// This will result in only coloring fragments adjacent to text, but leaving
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// background images (for example) untouched.
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for (int dy = -2; dy <= 2; dy += 2) {
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for (int dx = -2; dx <= 2; dx += 2) {
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float4 neighbor = shaderTexture.Sample(samplerState, tex, int2(dx, dy));
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color.a += neighbor.a;
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}
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}
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return color;
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}
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