Implement unorm_rgba8 and unorm_rg8 vertex formats.

Backend support implemented in GL, Metal and D3D12.
Support for unorm values in the GL backend requires a
utility function to indicate if the format's components
are normalized.

Note that unorm_r8 is only supported on more recent MacOS SDKs (10.13),
so it's omitted for now.

next.json

@@ -1222,7 +1222,9 @@
             {"value": 0, "name": "float r32 g32 b32 a32"},
             {"value": 1, "name": "float r32 g32 b32"},
             {"value": 2, "name": "float r32 g32"},
-            {"value": 3, "name": "float r32"}
+            {"value": 3, "name": "float r32"},
+            {"value": 4, "name": "unorm r8 g8 b8 a8"},
+            {"value": 5, "name": "unorm r8 g8"}
         ]
     },
     "void": {

src/backend/InputState.cpp

@@ -35,10 +35,12 @@ namespace backend {
     uint32_t VertexFormatNumComponents(nxt::VertexFormat format) {
         switch (format) {
             case nxt::VertexFormat::FloatR32G32B32A32:
+            case nxt::VertexFormat::UnormR8G8B8A8:
                 return 4;
             case nxt::VertexFormat::FloatR32G32B32:
                 return 3;
             case nxt::VertexFormat::FloatR32G32:
+            case nxt::VertexFormat::UnormR8G8:
                 return 2;
             case nxt::VertexFormat::FloatR32:
                 return 1;
@@ -47,18 +49,25 @@ namespace backend {
         }
     }
 
-    size_t VertexFormatSize(nxt::VertexFormat format) {
+    size_t VertexFormatComponentSize(nxt::VertexFormat format) {
         switch (format) {
             case nxt::VertexFormat::FloatR32G32B32A32:
             case nxt::VertexFormat::FloatR32G32B32:
             case nxt::VertexFormat::FloatR32G32:
             case nxt::VertexFormat::FloatR32:
-                return VertexFormatNumComponents(format) * sizeof(float);
+                return sizeof(float);
+            case nxt::VertexFormat::UnormR8G8B8A8:
+            case nxt::VertexFormat::UnormR8G8:
+                return sizeof(uint8_t);
             default:
                 UNREACHABLE();
         }
     }
 
+    size_t VertexFormatSize(nxt::VertexFormat format) {
+        return VertexFormatNumComponents(format) * VertexFormatComponentSize(format);
+    }
+
     // InputStateBase
 
     InputStateBase::InputStateBase(InputStateBuilder* builder) {

src/backend/InputState.h

@@ -29,6 +29,7 @@ namespace backend {
 
     size_t IndexFormatSize(nxt::IndexFormat format);
     uint32_t VertexFormatNumComponents(nxt::VertexFormat format);
+    size_t VertexFormatComponentSize(nxt::VertexFormat format);
     size_t VertexFormatSize(nxt::VertexFormat format);
 
     class InputStateBase : public RefCounted {

src/backend/d3d12/InputStateD3D12.cpp

@@ -28,6 +28,10 @@ namespace backend { namespace d3d12 {
                 return DXGI_FORMAT_R32G32_FLOAT;
             case nxt::VertexFormat::FloatR32:
                 return DXGI_FORMAT_R32_FLOAT;
+            case nxt::VertexFormat::UnormR8G8B8A8:
+                return DXGI_FORMAT_R8G8B8A8_UNORM;
+            case nxt::VertexFormat::UnormR8G8:
+                return DXGI_FORMAT_R8G8_UNORM;
             default:
                 UNREACHABLE();
         }

src/backend/metal/InputStateMTL.mm

@@ -30,6 +30,10 @@ namespace backend { namespace metal {
                     return MTLVertexFormatFloat2;
                 case nxt::VertexFormat::FloatR32:
                     return MTLVertexFormatFloat;
+                case nxt::VertexFormat::UnormR8G8B8A8:
+                    return MTLVertexFormatUChar4Normalized;
+                case nxt::VertexFormat::UnormR8G8:
+                    return MTLVertexFormatUChar2Normalized;
             }
         }
 

src/backend/opengl/CommandBufferGL.cpp

@@ -49,6 +49,24 @@ namespace backend { namespace opengl {
                 case nxt::VertexFormat::FloatR32G32:
                 case nxt::VertexFormat::FloatR32:
                     return GL_FLOAT;
+                case nxt::VertexFormat::UnormR8G8B8A8:
+                case nxt::VertexFormat::UnormR8G8:
+                    return GL_UNSIGNED_BYTE;
+                default:
+                    UNREACHABLE();
+            }
+        }
+
+        GLboolean VertexFormatIsNormalized(nxt::VertexFormat format) {
+            switch (format) {
+                case nxt::VertexFormat::FloatR32G32B32A32:
+                case nxt::VertexFormat::FloatR32G32B32:
+                case nxt::VertexFormat::FloatR32G32:
+                case nxt::VertexFormat::FloatR32:
+                    return GL_FALSE;
+                case nxt::VertexFormat::UnormR8G8B8A8:
+                case nxt::VertexFormat::UnormR8G8:
+                    return GL_TRUE;
                 default:
                     UNREACHABLE();
             }
@@ -184,9 +202,10 @@ namespace backend { namespace opengl {
                         auto components = VertexFormatNumComponents(attribute.format);
                         auto formatType = VertexFormatType(attribute.format);
 
+                        GLboolean normalized = VertexFormatIsNormalized(attribute.format);
                         glBindBuffer(GL_ARRAY_BUFFER, buffer);
                         glVertexAttribPointer(
-                            location, components, formatType, GL_FALSE, input.stride,
+                            location, components, formatType, normalized, input.stride,
                             reinterpret_cast<void*>(
                                 static_cast<intptr_t>(offset + attribute.offset)));
                     }

src/tests/end2end/InputStateTests.cpp

@@ -44,10 +44,12 @@ class InputStateTest : public NXTTest {
             EXPECT_TRUE(component >= 0 && component < 4);
             switch (format) {
                 case VertexFormat::FloatR32G32B32A32:
+                case VertexFormat::UnormR8G8B8A8:
                     return component >= 4;
                 case VertexFormat::FloatR32G32B32:
                     return component >= 3;
                 case VertexFormat::FloatR32G32:
+                case VertexFormat::UnormR8G8:
                     return component >= 2;
                 case VertexFormat::FloatR32:
                     return component >= 1;