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avoid unnecessary conversion of colours between half4 to float4 and back again

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a dinosaur 2024-08-25 15:14:00 +10:00
parent 428b142bf2
commit 8de398ce13
3 changed files with 22 additions and 9 deletions
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14
Sources/Voxelotl/Renderer/Renderer.swift
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@ -353,9 +353,9 @@ public class Renderer {
var fragUniforms = FragmentShaderUniforms(
cameraPosition: camera.position,
directionalLight: normalize(environment.lightDirection),
ambientColor: SIMD4(Color<Float>(material.ambient)),
diffuseColor: SIMD4(Color<Float>(material.diffuse)),
specularColor: SIMD4(Color<Float>(material.specular)),
ambientColor: material.ambient.reinterpretUShort,
diffuseColor: material.diffuse.reinterpretUShort,
specularColor: material.specular.reinterpretUShort,
specularIntensity: material.gloss)
let numInstances = instances.count
@ -384,7 +384,7 @@ public class Renderer {
.scale(instance.scale)
data[i] = VertexShaderInstance(
model: model, normalModel: model.inverse.transpose,
color: SIMD4(Color<Float>(instance.color)))
color: instance.color.reinterpretUShort)
}
}
instanceBuffer.didModifyRange(0..<instancesBytes)
@ -428,6 +428,12 @@ fileprivate extension MTLCullMode {
}
}
fileprivate extension Color where T == Float16 {
var reinterpretUShort: SIMD4<UInt16> {
.init(self.r.bitPattern, self.g.bitPattern, self.b.bitPattern, self.a.bitPattern)
}
}
enum RendererError: Error {
case initFailure(_ message: String)
case loadFailure(_ message: String)

6
Sources/Voxelotl/shader.metal
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@ -45,18 +45,18 @@ fragment half4 fragmentMain(
// Compute diffuse component
float lambert = metal::dot(normal, lightVec);
float diffuseAmount = metal::max(0.0, lambert);
half4 diffuse = half4(u.diffuseColor) * diffuseAmount;
half4 diffuse = u.diffuseColor * diffuseAmount;
// Compute specular component (blinn-phong)
float specularAngle = metal::max(0.0, metal::dot(halfDir, normal));
float specularTerm = metal::pow(specularAngle, u.specularIntensity);
// smoothstep hack to ensure highlight tapers gracefully at grazing angles
float specularAmount = specularTerm * metal::smoothstep(0, 2, lambert * u.specularIntensity);
half4 specular = half4(u.specularColor) * specularAmount;
half4 specular = u.specularColor * specularAmount;
// Sample texture & vertex color to get albedo
half4 albedo = texture.sample(sampler, in.texCoord);
albedo *= in.color;
return albedo * (half4(u.ambientColor) + diffuse) + specular;
return albedo * (u.ambientColor + diffuse) + specular;
}

11
Sources/Voxelotl/shadertypes.h
View File

@ -10,6 +10,13 @@
#include <simd/simd.h>
// HACK: allow passing SIMD4<Float16> to shader while `simd_half4` is beta
#ifdef __METAL_VERSION__
typedef half4 color_half4;
#else
typedef simd_ushort4 color_half4;
#endif
typedef NS_ENUM(NSInteger, VertexShaderInputIdx) {
VertexShaderInputIdxVertices = 0,
VertexShaderInputIdxInstance = 1,
@ -25,7 +32,7 @@ typedef struct {
typedef struct {
matrix_float4x4 model;
matrix_float4x4 normalModel;
vector_float4 color;
color_half4 color;
} VertexShaderInstance;
typedef struct {
@ -38,7 +45,7 @@ typedef NS_ENUM(NSInteger, FragmentShaderInputIdx) {
typedef struct {
vector_float3 cameraPosition, directionalLight;
vector_float4 ambientColor, diffuseColor, specularColor;
color_half4 ambientColor, diffuseColor, specularColor;
float specularIntensity;
} FragmentShaderUniforms;