Pica: Add vertex shader implementation.

1 files changed, 211 insertions, 0 deletions

diff --git a/src/video_core/vertex_shader.h b/src/video_core/vertex_shader.h
new file mode 100644
index 00000000..1b71e367
--- /dev/null
+++ b/src/video_core/vertex_shader.h
@@ -0,0 +1,211 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <initializer_list>
+
+#include <common/common_types.h>
+
+#include "math.h"
+#include "pica.h"
+
+namespace Pica {
+
+namespace VertexShader {
+
+struct InputVertex {
+    Math::Vec4<float24> attr[16];
+};
+
+struct OutputVertex {
+    OutputVertex() = default;
+
+    // VS output attributes
+    Math::Vec4<float24> pos;
+    Math::Vec4<float24> dummy; // quaternions (not implemented, yet)
+    Math::Vec4<float24> color;
+    Math::Vec2<float24> tc0;
+    float24 tc0_v;
+
+    // Padding for optimal alignment
+    float24 pad[14];
+
+    // Attributes used to store intermediate results
+
+    // position after perspective divide
+    Math::Vec3<float24> screenpos;
+
+    // Linear interpolation
+    // factor: 0=this, 1=vtx
+    void Lerp(float24 factor, const OutputVertex& vtx) {
+        pos = pos * factor + vtx.pos * (float24::FromFloat32(1) - factor);
+
+        // TODO: Should perform perspective correct interpolation here...
+        tc0 = tc0 * factor + vtx.tc0 * (float24::FromFloat32(1) - factor);
+
+        screenpos = screenpos * factor + vtx.screenpos * (float24::FromFloat32(1) - factor);
+
+        color = color * factor + vtx.color * (float24::FromFloat32(1) - factor);
+    }
+
+    // Linear interpolation
+    // factor: 0=v0, 1=v1
+    static OutputVertex Lerp(float24 factor, const OutputVertex& v0, const OutputVertex& v1) {
+        OutputVertex ret = v0;
+        ret.Lerp(factor, v1);
+        return ret;
+    }
+};
+static_assert(std::is_pod<OutputVertex>::value, "Structure is not POD");
+
+union Instruction {
+    enum class OpCode : u32 {
+        ADD = 0x0,
+        DP3 = 0x1,
+        DP4 = 0x2,
+
+        MUL = 0x8,
+
+        MAX = 0xC,
+        MIN = 0xD,
+        RCP = 0xE,
+        RSQ = 0xF,
+
+        MOV = 0x13,
+
+        RET = 0x21,
+        FLS = 0x22, // Flush
+        CALL = 0x24,
+    };
+
+    std::string GetOpCodeName() const {
+        std::map<OpCode, std::string> map = {
+            { OpCode::ADD, "ADD" },
+            { OpCode::DP3, "DP3" },
+            { OpCode::DP4, "DP4" },
+            { OpCode::MUL, "MUL" },
+            { OpCode::MAX, "MAX" },
+            { OpCode::MIN, "MIN" },
+            { OpCode::RCP, "RCP" },
+            { OpCode::RSQ, "RSQ" },
+            { OpCode::MOV, "MOV" },
+            { OpCode::RET, "RET" },
+            { OpCode::FLS, "FLS" },
+        };
+        auto it = map.find(opcode);
+        if (it == map.end())
+            return "UNK";
+        else
+            return it->second;
+    }
+
+    u32 hex;
+
+    BitField<0x1a, 0x6, OpCode> opcode;
+
+    // General notes:
+    //
+    // When two input registers are used, one of them uses a 5-bit index while the other
+    // one uses a 7-bit index. This is because at most one floating point uniform may be used
+    // as an input.
+
+
+    // Format used e.g. by arithmetic instructions and comparisons
+    // "src1" and "src2" specify register indices (i.e. indices referring to groups of 4 floats),
+    // while "dest" addresses individual floats.
+    union {
+        BitField<0x00, 0x5, u32> operand_desc_id;
+        BitField<0x07, 0x5, u32> src2;
+        BitField<0x0c, 0x7, u32> src1;
+        BitField<0x13, 0x7, u32> dest;
+    } common;
+
+    // Format used for flow control instructions ("if")
+    union {
+        BitField<0x00, 0x8, u32> num_instructions;
+        BitField<0x0a, 0xc, u32> offset_words;
+    } flow_control;
+};
+
+union SwizzlePattern {
+    u32 hex;
+
+    enum class Selector : u32 {
+        x = 0,
+        y = 1,
+        z = 2,
+        w = 3
+    };
+
+    Selector GetSelectorSrc1(int comp) const {
+        Selector selectors[] = {
+            src1_selector_0, src1_selector_1, src1_selector_2, src1_selector_3
+        };
+        return selectors[comp];
+    }
+
+    Selector GetSelectorSrc2(int comp) const {
+        Selector selectors[] = {
+            src2_selector_0, src2_selector_1, src2_selector_2, src2_selector_3
+        };
+        return selectors[comp];
+    }
+
+    bool DestComponentEnabled(int i) const {
+        return (dest_mask & (0x8 >> i));
+    }
+
+    std::string SelectorToString(bool src2) const {
+        std::map<Selector, std::string> map = {
+            { Selector::x, "x" },
+            { Selector::y, "y" },
+            { Selector::z, "z" },
+            { Selector::w, "w" }
+        };
+        std::string ret;
+        for (int i = 0; i < 4; ++i) {
+            ret += map.at(src2 ? GetSelectorSrc2(i) : GetSelectorSrc1(i));
+        }
+        return ret;
+    }
+
+    std::string DestMaskToString() const {
+        std::string ret;
+        for (int i = 0; i < 4; ++i) {
+            if (!DestComponentEnabled(i))
+                ret += "_";
+            else
+                ret += "xyzw"[i];
+        }
+        return ret;
+    }
+
+    // Components of "dest" that should be written to: LSB=dest.w, MSB=dest.x
+    BitField< 0, 4, u32> dest_mask;
+
+    BitField< 5, 2, Selector> src1_selector_3;
+    BitField< 7, 2, Selector> src1_selector_2;
+    BitField< 9, 2, Selector> src1_selector_1;
+    BitField<11, 2, Selector> src1_selector_0;
+
+    BitField<14, 2, Selector> src2_selector_3;
+    BitField<16, 2, Selector> src2_selector_2;
+    BitField<18, 2, Selector> src2_selector_1;
+    BitField<20, 2, Selector> src2_selector_0;
+
+    BitField<31, 1, u32> flag; // not sure what this means, maybe it's the sign?
+};
+
+void SubmitShaderMemoryChange(u32 addr, u32 value);
+void SubmitSwizzleDataChange(u32 addr, u32 value);
+
+OutputVertex RunShader(const InputVertex& input, int num_attributes);
+
+Math::Vec4<float24>& GetFloatUniform(u32 index);
+
+} // namespace
+
+} // namespace
+