Don't assign a `binding` to a `push_constant` buffer

Fixes #12

- This was a latent issue, but the previous commit brought it to the front.

- As indicated in #12, I don't allocate a descriptor-table slot to the block
  - Instead I allocate a `PushConstantBuffer`

- Unlike what #12 asks for, I don't use a different resource type for the contents of the block
  - Pretty much all the logic is easiest if these continue to be just plain `Uniform` data

1 files changed, 29 insertions, 0 deletions

diff --git a/source/slang/type-layout.cpp b/source/slang/type-layout.cpp
index 2977ee9b8..2e0f3035a 100644
--- a/source/slang/type-layout.cpp
+++ b/source/slang/type-layout.cpp
@@ -337,6 +337,19 @@ struct GLSLObjectLayoutRulesImpl : ObjectLayoutRulesImpl
 };
 GLSLObjectLayoutRulesImpl kGLSLObjectLayoutRulesImpl;
 
+struct GLSLPushConstantBufferObjectLayoutRulesImpl : GLSLObjectLayoutRulesImpl
+{
+    virtual SimpleLayoutInfo GetObjectLayout(ShaderParameterKind kind) override
+    {
+        // Special-case the layout for a constant-buffer, because we don't
+        // want it to allocate a descriptor-table slot
+        return SimpleLayoutInfo(LayoutResourceKind::PushConstantBuffer, 1);
+
+        return GLSLObjectLayoutRulesImpl::GetObjectLayout(kind);
+    }
+};
+GLSLPushConstantBufferObjectLayoutRulesImpl kGLSLPushConstantBufferObjectLayoutRulesImpl_;
+
 struct HLSLObjectLayoutRulesImpl : ObjectLayoutRulesImpl
 {
     virtual SimpleLayoutInfo GetObjectLayout(ShaderParameterKind kind) override
@@ -392,6 +405,7 @@ HLSLVaryingLayoutRulesImpl kHLSLVaryingOutputLayoutRulesImpl(LayoutResourceKind:
 struct GLSLLayoutRulesFamilyImpl : LayoutRulesFamilyImpl
 {
     virtual LayoutRulesImpl* getConstantBufferRules() override;
+    virtual LayoutRulesImpl* getPushConstantBufferRules() override;
     virtual LayoutRulesImpl* getTextureBufferRules() override;
     virtual LayoutRulesImpl* getVaryingInputRules() override;
     virtual LayoutRulesImpl* getVaryingOutputRules() override;
@@ -402,6 +416,7 @@ struct GLSLLayoutRulesFamilyImpl : LayoutRulesFamilyImpl
 struct HLSLLayoutRulesFamilyImpl : LayoutRulesFamilyImpl
 {
     virtual LayoutRulesImpl* getConstantBufferRules() override;
+    virtual LayoutRulesImpl* getPushConstantBufferRules() override;
     virtual LayoutRulesImpl* getTextureBufferRules() override;
     virtual LayoutRulesImpl* getVaryingInputRules() override;
     virtual LayoutRulesImpl* getVaryingOutputRules() override;
@@ -423,6 +438,10 @@ LayoutRulesImpl kStd430LayoutRulesImpl_ = {
     &kGLSLLayoutRulesFamilyImpl, &kStd430LayoutRulesImpl, &kGLSLObjectLayoutRulesImpl,
 };
 
+LayoutRulesImpl kGLSLPushConstantLayoutRulesImpl_ = {
+    &kGLSLLayoutRulesFamilyImpl, &kStd430LayoutRulesImpl, &kGLSLPushConstantBufferObjectLayoutRulesImpl_,
+};
+
 LayoutRulesImpl kGLSLVaryingInputLayoutRulesImpl_ = {
     &kGLSLLayoutRulesFamilyImpl, &kGLSLVaryingInputLayoutRulesImpl, &kGLSLObjectLayoutRulesImpl,
 };
@@ -460,6 +479,11 @@ LayoutRulesImpl* GLSLLayoutRulesFamilyImpl::getConstantBufferRules()
     return &kStd140LayoutRulesImpl_;
 }
 
+LayoutRulesImpl* GLSLLayoutRulesFamilyImpl::getPushConstantBufferRules()
+{
+    return &kGLSLPushConstantLayoutRulesImpl_;
+}
+
 LayoutRulesImpl* GLSLLayoutRulesFamilyImpl::getTextureBufferRules()
 {
     return nullptr;
@@ -492,6 +516,11 @@ LayoutRulesImpl* HLSLLayoutRulesFamilyImpl::getConstantBufferRules()
     return &kHLSLConstantBufferLayoutRulesImpl_;
 }
 
+LayoutRulesImpl* HLSLLayoutRulesFamilyImpl::getPushConstantBufferRules()
+{
+    return &kHLSLConstantBufferLayoutRulesImpl_;
+}
+
 LayoutRulesImpl* HLSLLayoutRulesFamilyImpl::getTextureBufferRules()
 {
     return nullptr;