transparent.hlsl

// This shader helps to add transparency for vim themes that use xterm colors.

// Define map for PS input
struct PSInput {
  float4 pos : SV_POSITION;
  float2 uv : TEXCOORD0;
};

// The terminal graphics as a texture
Texture2D shaderTexture : register(t0);
SamplerState samplerState : register(s0);

// Terminal settings such as the resolution of the texture
cbuffer PixelShaderSettings : register(b0) {
  // The number of seconds since the pixel shader was enabled
  float  Time;
  // UI Scale
  float  Scale;
  // Resolution of the shaderTexture
  float2 Resolution;
  // Background color as rgba
  float4 Background;
};

// Settings - Debug
#define DEBUG                   0
#define DEBUG_ROTATION          0.25
#define DEBUG_SEGMENTS          1
#define DEBUG_OFFSET            0.425
#define DEBUG_WIDTH             0.15
#define SHOW_UV                 0
#define SHOW_POS                0

#if SHADERed
// Must be inlined to the shader or it breaks single-step debugging
PSInput patchCoordinates(PSInput pin);

struct DebugOut {
  bool show;
  float4 color;
};
DebugOut debug(float4 pos, float2 uv);
#endif

// Set the color that is supposed to be transparent
static const float3 chromaKey = float3(8.0f / 0xFF, 8.0f / 0xFF, 8.0f / 0xFF);

float4 main(PSInput pin) : SV_TARGET
{
  // Use pos and uv in the shader the same as we might use
  // Time, Scale, Resolution, and Background. Unlike those,
  // they are local variables in this implementation and should
  // be passed to any functions using them.
  
  float4 pos = pin.pos;
  float2 uv = pin.uv;
  
  #if SHADERed
  // Must be inlined to the shader or it breaks single-step debugging
  // Patches the pin pos and uv
  PSInput patchedPin = patchCoordinates(pin);
  pos = patchedPin.pos;
  uv = patchedPin.uv;

  // Patches in the UV Debug output
  DebugOut debugOut = debug(pos, uv);
  if (debugOut.show) { return debugOut.color; }
  #endif

//-- Shader goes here --//
  float4 color = shaderTexture.Sample(samplerState, uv);
	
  // Filter by chroma key
  if(color.r == chromaKey.r && color.g == chromaKey.g && color.b == chromaKey.b)
  {
    return float4(0.0f, 0.0f, 0.0f, 0.0f);
  }

  return color;
//-- Shader goes here --//
}

#if SHADERed
#include "SHADERed/PS-DebugPatch.hlsl"
#include "SHADERed/PS-CoordinatesPatch.hlsl"
#endif