- improve handling of descriptor layout and resource aliasing

examples/v2/v2_examples.hlsl

@@ -34,6 +34,10 @@ cbuffer per_pass_vs : register(b1) {
     float4   test;
 };
 
+struct cbuffer_data {
+    float4 data2;
+};
+
 SamplerState decl_sampler : register(s0);
 
 ConstantBuffer<sb_sb> decl_cbuffer_array[] : register(b2);
@@ -46,6 +50,13 @@ Texture1D decl_texture1d : register(t0);
 Texture2D decl_texture2d : register(t1);
 Texture3D decl_texture3d : register(t2);
 
+// alias resource types types on t0
+Texture2D textures[] : register(t0);
+TextureCube cubemaps[] : register(t0);
+Texture2DArray texture_arrays[] : register(t0);
+Texture3D volume_textures[] : register(t0);
+ConstantBuffer<cbuffer_data> cbuffers[] : register(b0);
+
 void test_func() {
     decl_texture1d;
     decl_cbuffer_array;
@@ -104,4 +115,21 @@ vs_output vs_main_separate_elements(float4 pos : POSITION, float4 tex : TEXCOORD
 ps_output ps_main() {
     test_func2();
     return ps_output_default();
+}
+
+vs_output vs_test_bindless_aliasing(vs_input input) {
+    return vs_output_default();
+}
+
+ps_output ps_test_bindless_aliasing() {
+    test_func();
+    // using this void cast touches the resources so they are detected by pmfx and compiled in
+    (textures);
+    (cubemaps);
+    (texture_arrays);
+    (volume_textures);
+
+    // cbuffers go on a different slot
+    (cbuffers);
+    return ps_output_default();
 }

examples/v2/v2_examples.pmfx

@@ -56,5 +56,9 @@
             ps: ps_main
             blend_state: additive
         }
+        bindless: {
+            vs: vs_test_bindless_aliasing
+            ps: ps_test_bindless_aliasing
+        }
     }
 }

pmfx_pipeline.py

@@ -518,14 +518,41 @@ def generate_descriptor_layout(pmfx, pmfx_pipeline, resources):
                 "num_descriptors": get_descriptor_array_size(resource)
             }
             descriptor_layout["bindings"].append(binding)
+
+    # combine bindings on the same slot (allow resource type aliasing)
+    combined_bindings = dict()
+    for binding in  descriptor_layout["bindings"]:
+        bh = pmfx_hash({
+            "shader_register": binding["shader_register"],
+            "register_space": binding["register_space"],
+            "register_space": binding["register_space"],
+            "binding_type": binding["binding_type"]
+        })
+        if bh not in combined_bindings:
+            combined_bindings[bh] = binding
+        else:
+            cur = combined_bindings[bh]
+            # extend visibility
+            if binding["visibility"] != cur["visibility"]:
+                cur["visibility"] = "All"
+
     # sort bindings in index order
     sorted_bindings = list()
-    for binding in descriptor_layout["bindings"]:
-        insert_pos = 0
-        for i in range(0, len(sorted_bindings)):
-            if binding["shader_register"] < sorted_bindings[i]["shader_register"]:
-                insert_pos = i
-        sorted_bindings.insert(insert_pos, binding)
+    for binding in combined_bindings.values():
+        sorted_bindings.append(binding)
+
+    # bubble sort sort them
+    sorted = False
+    while not sorted:
+        sorted = True
+        for i in range(0, len(sorted_bindings) - 1):
+            j = i + 1
+            if sorted_bindings[j]["shader_register"] < sorted_bindings[i]["shader_register"]:
+                temp = sorted_bindings[j]["shader_register"]
+                sorted_bindings[j]["shader_register"] = sorted_bindings[i]["shader_register"]
+                sorted_bindings[i]["shader_register"] = temp
+                sorted = False
+
     descriptor_layout["bindings"] = sorted_bindings
     return descriptor_layout