// license:BSD-3-Clause // copyright-holders:Ryan Holtz,Themaister,ImJezze //----------------------------------------------------------------------------- // Pre-scale Effect // // Uses the hardware bilinear interpolator to avoid having to sample 4 times manually. // // https://github.com/libretro/common-shaders/blob/master/retro/shaders/sharp-bilinear.cg //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- // Sampler Definitions //----------------------------------------------------------------------------- texture Diffuse; sampler DiffuseSampler = sampler_state { Texture = ; MipFilter = LINEAR; MinFilter = LINEAR; MagFilter = LINEAR; AddressU = CLAMP; AddressV = CLAMP; AddressW = CLAMP; }; //----------------------------------------------------------------------------- // Vertex Definitions //----------------------------------------------------------------------------- struct VS_OUTPUT { float4 Position : POSITION; float2 TexCoord : TEXCOORD0; }; struct VS_INPUT { float4 Position : POSITION; float4 Color : COLOR0; float2 TexCoord : TEXCOORD0; float2 Unused : TEXCOORD1; }; struct PS_INPUT { float2 TexCoord : TEXCOORD0; }; //----------------------------------------------------------------------------- // Pre-scale Vertex Shader //----------------------------------------------------------------------------- uniform float2 ScreenDims; uniform float2 TargetDims; uniform float2 SourceDims; VS_OUTPUT vs_main(VS_INPUT Input) { VS_OUTPUT Output = (VS_OUTPUT)0; Output.Position = float4(Input.Position.xyz, 1.0f); Output.Position.xy /= ScreenDims; Output.Position.y = 1.0f - Output.Position.y; // flip y Output.Position.xy -= 0.5f; // center Output.Position.xy *= 2.0f; // zoom Output.TexCoord = Input.TexCoord; Output.TexCoord += 0.5f / TargetDims; // half texel offset correction (DX9) return Output; } //----------------------------------------------------------------------------- // Pre-scale Pixel Shader //----------------------------------------------------------------------------- float4 ps_main(PS_INPUT Input) : COLOR { float2 Scale = TargetDims / SourceDims; float2 TexelDims = Input.TexCoord * SourceDims; float2 i = floor(TexelDims); float2 s = frac(TexelDims); // Figure out where in the texel to sample to get the correct pre-scaled bilinear. float2 CenterDistance = s - 0.5f; float2 RegionRange = 0.5f - 0.5f / Scale; float2 f = (CenterDistance - clamp(CenterDistance, -RegionRange, RegionRange)) * Scale + 0.5f; float2 TexCoord = (i + f) / SourceDims; return tex2D(DiffuseSampler, TexCoord); } //----------------------------------------------------------------------------- // Pre-scale Technique //----------------------------------------------------------------------------- technique DefaultTechnique { pass Pass0 { Lighting = FALSE; VertexShader = compile vs_3_0 vs_main(); PixelShader = compile ps_3_0 ps_main(); } }