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Achieves a return of composite colour for RGB-producing machines.

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This commit is contained in:
Thomas Harte 2020-08-21 22:06:36 -04:00
parent d54b937ab6
commit bf6a0c9fc4
2 changed files with 32 additions and 13 deletions
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34
OSBindings/Mac/Clock Signal/ScanTarget/CSScanTarget.mm
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@ -25,7 +25,7 @@ struct Uniforms {
simd::float3x3 fromRGB;
float zoom;
simd::float2 offset;
float firCoefficients[8];
simd::float3 firCoefficients[8];
};
constexpr size_t NumBufferedScans = 2048;
@ -373,16 +373,33 @@ using BufferingScanTarget = Outputs::Display::BufferingScanTarget;
_compositionRenderPass.colorAttachments[0].loadAction = MTLLoadActionClear;
_compositionRenderPass.colorAttachments[0].storeAction = MTLStoreActionStore;
// TODO: set proper clear colour for S-Video.
// TODO: set proper clear colour for S-Video (and fragment function, below).
// TODO: work out fir coefficients, for real.
simd::float3 *const firCoefficients = uniforms()->firCoefficients;
const float cyclesPerLine = float(modals.cycles_per_line);
const float colourCyclesPerLine = float(modals.colour_cycle_numerator) / float(modals.colour_cycle_denominator);
SignalProcessing::FIRFilter filter(15, cyclesPerLine, 0.0f, 16.0f * cyclesPerLine / colourCyclesPerLine);
float *const firCoefficients = uniforms()->firCoefficients;
const auto calculatedCoefficients = filter.get_coefficients();
memcpy(firCoefficients, calculatedCoefficients.data(), calculatedCoefficients.size() * sizeof(float));
if(isSVideoOutput) {
// In S-Video, don't filter luminance.
for(size_t c = 0; c < 7; ++c) {
firCoefficients[c].x = 0.0f;
}
firCoefficients[7].x = 1.0f;
} else {
// In composite, filter luminance gently.
SignalProcessing::FIRFilter luminancefilter(15, cyclesPerLine, 0.0f, colourCyclesPerLine * 0.75f);
const auto calculatedCoefficients = luminancefilter.get_coefficients();
for(size_t c = 0; c < 8; ++c) {
firCoefficients[c].x = calculatedCoefficients[c];
}
}
// Whether S-Video or composite, apply the same relatively strong filter to colour channels.
SignalProcessing::FIRFilter chrominancefilter(15, cyclesPerLine, 0.0f, colourCyclesPerLine * 0.125f);
const auto calculatedCoefficients = chrominancefilter.get_coefficients();
for(size_t c = 0; c < 8; ++c) {
firCoefficients[c].y = firCoefficients[c].z = calculatedCoefficients[c];
}
}
// Build the output pipeline.
@ -390,8 +407,7 @@ using BufferingScanTarget = Outputs::Display::BufferingScanTarget;
pipelineDescriptor.vertexFunction = [library newFunctionWithName:_isUsingCompositionPipeline ? @"lineToDisplay" : @"scanToDisplay"];
if(_isUsingCompositionPipeline) {
// TODO!
pipelineDescriptor.fragmentFunction = [library newFunctionWithName:@"convertComposite"];
pipelineDescriptor.fragmentFunction = [library newFunctionWithName:@"filterFragment"];
} else {
const bool isRGBOutput = modals.display_type == Outputs::Display::DisplayType::RGB;
pipelineDescriptor.fragmentFunction =

11
OSBindings/Mac/Clock Signal/ScanTarget/ScanTarget.metal
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@ -33,7 +33,7 @@ struct Uniforms {
// Describes the FIR filter in use; it'll be 15 coefficients but they're
// symmetrical around the centre.
float firCoefficients[8];
float3 firCoefficients[8];
};
namespace {
@ -270,8 +270,11 @@ float3 convertRed1Green1Blue1(SourceInterpolator vert, texture2d<ushort> texture
fragment float4 compositeSample##name(SourceInterpolator vert [[stage_in]], texture2d<pixelType> texture [[texture(0)]], constant Uniforms &uniforms [[buffer(0)]]) { \
const auto colour = uniforms.fromRGB * convert##name(vert, texture); \
const float2 colourSubcarrier = float2(sin(vert.colourPhase), cos(vert.colourPhase)); \
const float level = mix(colour.r, dot(colour.gb, colourSubcarrier), vert.colourAmplitude); \
return float4( \
float3(mix(colour.r, dot(colour.gb, colourSubcarrier), vert.colourAmplitude)), \
level, \
0.5 + 0.5*level*sin(vert.colourPhase),\
0.5 + 0.5*level*cos(vert.colourPhase),\
1.0 \
); \
}
@ -318,7 +321,7 @@ fragment float4 clearFragment() {
// MARK: - Conversion fragment shaders
fragment float4 convertComposite(CopyInterpolator vert [[stage_in]], texture2d<float> texture [[texture(0)]], constant Uniforms &uniforms [[buffer(0)]]) {
fragment float4 filterFragment(SourceInterpolator vert [[stage_in]], texture2d<float> texture [[texture(0)]], constant Uniforms &uniforms [[buffer(0)]]) {
const float3 colour =
uniforms.firCoefficients[0] * texture.sample(standardSampler, vert.textureCoordinates - float2(7.0, 0.0)).rgb +
uniforms.firCoefficients[1] * texture.sample(standardSampler, vert.textureCoordinates - float2(6.0, 0.0)).rgb +
@ -336,5 +339,5 @@ fragment float4 convertComposite(CopyInterpolator vert [[stage_in]], texture2d<f
uniforms.firCoefficients[1] * texture.sample(standardSampler, vert.textureCoordinates + float2(6.0, 0.0)).rgb +
uniforms.firCoefficients[0] * texture.sample(standardSampler, vert.textureCoordinates + float2(7.0, 0.0)).rgb;
return float4(colour, 1.0);
return float4(uniforms.toRGB * ((colour - float3(0.0, 0.5, 0.5)) * float3(1.0, 2.0 / vert.colourAmplitude, 2.0 / vert.colourAmplitude)), 1.0);
}