110 lines
2.9 KiB
HLSL
110 lines
2.9 KiB
HLSL
// license:BSD-3-Clause
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// copyright-holders:Ryan Holtz,Themaister,ImJezze
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//-----------------------------------------------------------------------------
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// Pre-scale Effect
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//
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// Uses the hardware bilinear interpolator to avoid having to sample 4 times manually.
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//
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// https://github.com/libretro/common-shaders/blob/master/retro/shaders/sharp-bilinear.cg
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//-----------------------------------------------------------------------------
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//-----------------------------------------------------------------------------
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// Sampler Definitions
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//-----------------------------------------------------------------------------
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texture Diffuse;
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sampler DiffuseSampler = sampler_state
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{
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Texture = <Diffuse>;
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MipFilter = LINEAR;
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MinFilter = LINEAR;
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MagFilter = LINEAR;
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AddressU = CLAMP;
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AddressV = CLAMP;
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AddressW = CLAMP;
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};
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//-----------------------------------------------------------------------------
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// Vertex Definitions
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//-----------------------------------------------------------------------------
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struct VS_OUTPUT
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{
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float4 Position : POSITION;
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float2 TexCoord : TEXCOORD0;
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};
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struct VS_INPUT
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{
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float4 Position : POSITION;
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float4 Color : COLOR0;
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float2 TexCoord : TEXCOORD0;
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};
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struct PS_INPUT
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{
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float2 TexCoord : TEXCOORD0;
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};
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//-----------------------------------------------------------------------------
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// Pre-scale Vertex Shader
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//-----------------------------------------------------------------------------
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uniform float2 ScreenDims;
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uniform float2 TargetDims;
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uniform float2 SourceDims;
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VS_OUTPUT vs_main(VS_INPUT Input)
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{
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VS_OUTPUT Output = (VS_OUTPUT)0;
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Output.Position = float4(Input.Position.xyz, 1.0f);
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Output.Position.xy /= ScreenDims;
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Output.Position.y = 1.0f - Output.Position.y; // flip y
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Output.Position.xy -= 0.5f; // center
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Output.Position.xy *= 2.0f; // zoom
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Output.TexCoord = Input.TexCoord;
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Output.TexCoord += 0.5f / TargetDims; // half texel offset correction (DX9)
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return Output;
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}
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//-----------------------------------------------------------------------------
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// Pre-scale Pixel Shader
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//-----------------------------------------------------------------------------
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float4 ps_main(PS_INPUT Input) : COLOR
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{
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float2 Scale = TargetDims / SourceDims;
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float2 TexelDims = Input.TexCoord * SourceDims;
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float2 i = floor(TexelDims);
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float2 s = frac(TexelDims);
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// Figure out where in the texel to sample to get the correct pre-scaled bilinear.
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float2 CenterDistance = s - 0.5f;
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float2 RegionRange = 0.5f - 0.5f / Scale;
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float2 f = (CenterDistance - clamp(CenterDistance, -RegionRange, RegionRange)) * Scale + 0.5f;
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float2 TexCoord = (i + f) / SourceDims;
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return tex2D(DiffuseSampler, TexCoord);
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}
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//-----------------------------------------------------------------------------
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// Pre-scale Technique
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//-----------------------------------------------------------------------------
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technique DefaultTechnique
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{
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pass Pass0
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{
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Lighting = FALSE;
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VertexShader = compile vs_3_0 vs_main();
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PixelShader = compile ps_3_0 ps_main();
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}
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}
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