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[kit] Pass target and feather values into the shaders

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This commit is contained in:
Eryn Wells 2017-08-25 11:19:09 -07:00
parent 6c06aadd37
commit 0b752984dc
4 changed files with 134 additions and 20 deletions
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20
MetaballsKit/Shaders.metal
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@ -64,8 +64,8 @@ passthroughVertexShader(uint vid [[vertex_id]],
float sampleAtPoint(float2, constant Ball*, int);
// Color samplers
float4 singleColor(float, float, float4);
float4 gradient2(float, float, float, float4, float4);
float4 singleColor(float, float, float, float4);
float4 gradient2(float, float, float, float, float4, float4);
// Helpers
float mapValueFromRangeOntoRange(float, float, float, float, float);
@ -76,17 +76,18 @@ sampleToColorShader(RasterizerData in [[stage_in]],
constant Parameters& parameters [[buffer(0)]],
constant Ball* balls [[buffer(1)]])
{
const float target = 1.0;
const float target = parameters.target;
const float feather = parameters.feather;
const float sample = sampleAtPoint(in.position.xy, balls, parameters.numberOfBalls);
const float blend = in.position.x / parameters.size.x;
float4 out;
switch (parameters.colorStyle) {
case SingleColor:
out = singleColor(sample, target, parameters.colors[0]);
out = singleColor(sample, target, feather, parameters.colors[0]);
break;
case Gradient2Horizontal:
out = gradient2(sample, target, blend, parameters.colors[0], parameters.colors[1]);
out = gradient2(sample, target, feather, blend, parameters.colors[0], parameters.colors[1]);
break;
}
@ -112,15 +113,17 @@ sampleAtPoint(float2 point,
float4
singleColor(float sample,
float target,
float feather,
float4 color)
{
float4 out;
if (sample > 1.0) {
if (sample > target) {
out = color;
}
// Feather the alpha value.
const float a = clamp(mapValueFromRangeOntoRange(sample, 0.75 * target, target, 0, 1), 0.0, 1.0);
const float mappedAlpha = mapValueFromRangeOntoRange(sample, (1.0 - feather) * target, target, 0, 1);
const float a = clamp(mappedAlpha, 0.0, 1.0);
out = float4(out.xyz, a);
return out;
@ -129,12 +132,13 @@ singleColor(float sample,
float4
gradient2(float sample,
float target,
float feather,
float normalizedBlend,
float4 fromColor,
float4 toColor)
{
float4 blendedColor = averageTwoColors(normalizedBlend, fromColor, toColor);
float4 out = singleColor(sample, target, blendedColor);
float4 out = singleColor(sample, target, feather, blendedColor);
return out;
}