video_core: Refactor GPU interface

src/video_core/pica/packed_attribute.h

@@ -0,0 +1,74 @@
+// Copyright 2023 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <boost/serialization/binary_object.hpp>
+
+#include "common/vector_math.h"
+#include "video_core/pica_types.h"
+
+namespace Pica {
+
+/**
+ * Uniforms and fixed attributes are written in a packed format such that four float24 values are
+ * encoded in three 32-bit numbers. Uniforms can also encode four float32 values in four 32-bit
+ * numbers. We write to internal memory once a full vector is written.
+ */
+struct PackedAttribute {
+    std::array<u32, 4> buffer{};
+    u32 index{};
+
+    /// Places a word to the queue and returns true if the queue becomes full.
+    constexpr bool Push(u32 word, bool is_float32 = false) {
+        buffer[index++] = word;
+        return (index >= 4 && is_float32) || (index >= 3 && !is_float32);
+    }
+
+    /// Resets the queue discarding previous entries.
+    constexpr void Reset() {
+        index = 0;
+    }
+
+    /// Returns the queue contents with either float24 or float32 interpretation.
+    constexpr Common::Vec4<f24> Get(bool is_float32 = false) {
+        Reset();
+        if (is_float32) {
+            return AsFloat32();
+        } else {
+            return AsFloat24();
+        }
+    }
+
+private:
+    /// Decodes the queue contents with float24 transfer mode.
+    constexpr Common::Vec4<f24> AsFloat24() const {
+        const u32 x = buffer[2] & 0xFFFFFF;
+        const u32 y = ((buffer[1] & 0xFFFF) << 8) | ((buffer[2] >> 24) & 0xFF);
+        const u32 z = ((buffer[0] & 0xFF) << 16) | ((buffer[1] >> 16) & 0xFFFF);
+        const u32 w = buffer[0] >> 8;
+        return Common::Vec4<f24>{f24::FromRaw(x), f24::FromRaw(y), f24::FromRaw(z),
+                                 f24::FromRaw(w)};
+    }
+
+    /// Decodes the queue contents with float32 transfer mode.
+    constexpr Common::Vec4<f24> AsFloat32() const {
+        Common::Vec4<f24> uniform;
+        for (u32 i = 0; i < 4; i++) {
+            const f32 buffer_value = std::bit_cast<f32>(buffer[i]);
+            uniform[3 - i] = f24::FromFloat32(buffer_value);
+        }
+        return uniform;
+    }
+
+private:
+    template <class Archive>
+    void serialize(Archive& ar, const u32) {
+        ar& buffer;
+        ar& index;
+    }
+    friend class boost::serialization::access;
+};
+
+} // namespace Pica