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// shader.slang
// This module is part of the `reflection-parameter-blocks`
// example program.
//
// This module is split out from the files that define
// individual programs, so that we can share some type
// definitions and utility functions between all of
// the programs and keep them focused on just defining
// the shader entry points.
struct Mesh
{
float4x4 modelToWorld;
float4x4 modelToWorld_inverseTranspose;
}
struct Material
{
Texture2D albedoMap;
Texture2D glossMap;
Texture2D normalMap;
SamplerState sampler;
}
interface ILight
{
}
struct DirectionalLight : ILight
{
float3 dir;
float3 intensity;
}
struct ShadowedLight<L : ILight> : ILight
{
L light;
Texture2D shadowMap;
SamplerComparisonState shadowSampler;
float4x4 worldToShadow;
}
struct EnvironmentMap
{
TextureCube texture;
SamplerState sampler;
}
struct Environment
{
ShadowedLight<DirectionalLight> sunLight;
EnvironmentMap envMap;
RWStructuredBuffer<float4> output;
}
struct View
{
float4x4 worldToView;
float4x4 viewToProj;
}
// While the Slang compilation library will *reflect* all of
// the shader parameters that a program declares,
// back-ends (such as the SPIR-V code generator) will often
// strip out parameters that are not used as part of the
// computation that a shader performs.
//
// When shader parameters are stripped from the output
// binary code, the runtime system for a particular API
// (e.g., the Vulkan validation layer) cannot check
// whether a program is correctly handling the binding
// of those parameters.
//
// Our example entry points will thus make use of some
// utility routines that serve the purpose of allowing
// us to ensure that specific parameters are seen as
// "used" during code generation.
void use(inout float4 r, float4 v) { r += v; }
void use(inout float4 r, float3 v) { r.xyz += v; }
void use(inout float4 r, Texture2D t, SamplerState s)
{
use(r, t.SampleLevel(s, r.xy, 0));
}
void use(inout float4 r, RWStructuredBuffer<float4> b)
{
use(r, b[int(r.x)]);
b[int(r.x)] = r;
}
void use(inout float4 r, Environment e)
{
use(r, e.sunLight.light.dir);
use(r, e.output);
}
void use(inout float4 r, View v)
{
use(r, v.worldToView[0]);
}
void use(inout float4 r, Material m)
{
use(r, m.normalMap, m.sampler);
}
void use(inout float4 r, Mesh m)
{
use(r, m.modelToWorld[0]);
}
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