62 lines
2.0 KiB
HLSL
62 lines
2.0 KiB
HLSL
SamplerState pointSampler
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{
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Filter = MIN_MAG_MIP_POINT; // Nearest-neighbor
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AddressU = Wrap;
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AddressV = Wrap;
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};
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Texture2D diffuseTexture : register(t0);
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struct PSInput
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{
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float4 position : SV_POSITION;
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float2 texcoord : TEXCOORD0;
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};
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float ditherPattern2x2[4] = {
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0.0, 0.5,
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0.75, 0.25
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};
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float4 mainPS(PSInput input) : SV_TARGET
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{
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// Sample texture with nearest-neighbor
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float4 color = diffuseTexture.Sample(pointSampler, input.texcoord);
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// Optional: Affine distortion effect
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// If you want to simulate affine warping, you could do some screen-space
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// dependent manipulation of texcoords. For simplicity, we won't do that here,
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// but one trick is to modify the texcoord by input.position.z or w in some
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// simplified manner. The vertex shader step is often enough to simulate "no perspective".
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// Dithering (optional):
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// Compute a screen-space coordinate from SV_POSITION
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// Use a small dithering pattern
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int x = (int)input.position.x;
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int y = (int)input.position.y;
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int idx = (y & 1) * 2 + (x & 1);
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float dither = ditherPattern2x2[idx];
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// To simulate PS1 color quantization (e.g. to 5 bits for R,G,B):
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// We'll quantize each channel.
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// Suppose colorBitDepth.x = 5 means 5 bits for R/G/B, that’s 32 steps.
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float stepsRGB = pow(2.0, colorBitDepth.x);
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float stepsA = pow(2.0, colorBitDepth.y);
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// Add dithering before quantization to reduce banding
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// Adjust dithering scale if desired
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float ditherStrength = 1.0 / stepsRGB; // dither scale can be tweaked
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float4 colorDithered = color + ditherStrength * dither;
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// Clamp after dithering
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colorDithered = saturate(colorDithered);
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// Quantize
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float3 quantizedRGB = round(colorDithered.rgb * (stepsRGB - 1.0)) / (stepsRGB - 1.0);
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float quantizedA = round(colorDithered.a * (stepsA - 1.0)) / (stepsA - 1.0);
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float4 finalColor = float4(quantizedRGB, quantizedA);
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return finalColor;
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}
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