From dadd192b30d547dfa078057796a5ae16820eb4be Mon Sep 17 00:00:00 2001
From: ReinUsesLisp <reinuseslisp@airmail.cc>
Date: Thu, 20 May 2021 02:18:52 -0300
Subject: glasm: Implement ImageRead

---
 .../backend/glasm/emit_context.cpp                 | 10 +++++
 src/shader_recompiler/backend/glasm/emit_context.h |  2 +
 src/shader_recompiler/backend/glasm/emit_glasm.cpp |  3 +-
 .../backend/glasm/emit_glasm_image.cpp             | 45 ++++++++++++++++++++--
 4 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/src/shader_recompiler/backend/glasm/emit_context.cpp b/src/shader_recompiler/backend/glasm/emit_context.cpp
index 463930a18..8f418936e 100644
--- a/src/shader_recompiler/backend/glasm/emit_context.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_context.cpp
@@ -82,6 +82,16 @@ EmitContext::EmitContext(IR::Program& program, Bindings& bindings, const Profile
             Add("OUTPUT out_attr{}[]={{result.attrib[{}..{}]}};", index, index, index);
         }
     }
+    image_buffer_bindings.reserve(program.info.image_buffer_descriptors.size());
+    for (const auto& desc : program.info.image_buffer_descriptors) {
+        image_buffer_bindings.push_back(bindings.image);
+        bindings.image += desc.count;
+    }
+    image_bindings.reserve(program.info.image_descriptors.size());
+    for (const auto& desc : program.info.image_descriptors) {
+        image_bindings.push_back(bindings.image);
+        bindings.image += desc.count;
+    }
     texture_buffer_bindings.reserve(program.info.texture_buffer_descriptors.size());
     for (const auto& desc : program.info.texture_buffer_descriptors) {
         texture_buffer_bindings.push_back(bindings.texture);
diff --git a/src/shader_recompiler/backend/glasm/emit_context.h b/src/shader_recompiler/backend/glasm/emit_context.h
index dd1f9ac9f..d5bab48ea 100644
--- a/src/shader_recompiler/backend/glasm/emit_context.h
+++ b/src/shader_recompiler/backend/glasm/emit_context.h
@@ -60,7 +60,9 @@ public:
     const Profile& profile;
 
     std::vector<u32> texture_buffer_bindings;
+    std::vector<u32> image_buffer_bindings;
     std::vector<u32> texture_bindings;
+    std::vector<u32> image_bindings;
 
     Stage stage{};
     std::string_view stage_name = "invalid";
diff --git a/src/shader_recompiler/backend/glasm/emit_glasm.cpp b/src/shader_recompiler/backend/glasm/emit_glasm.cpp
index 9dc0cacbe..3910d00ee 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_glasm.cpp
@@ -270,7 +270,8 @@ void SetupOptions(const IR::Program& program, const Profile& profile, std::strin
               "OPTION NV_shader_storage_buffer;"
               "OPTION NV_gpu_program_fp64;"
               "OPTION NV_bindless_texture;"
-              "OPTION ARB_derivative_control;";
+              "OPTION ARB_derivative_control;"
+              "OPTION EXT_shader_image_load_formatted;";
     if (info.uses_int64_bit_atomics) {
         header += "OPTION NV_shader_atomic_int64;";
     }
diff --git a/src/shader_recompiler/backend/glasm/emit_glasm_image.cpp b/src/shader_recompiler/backend/glasm/emit_glasm_image.cpp
index ab5a694fd..beee9cf06 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm_image.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_glasm_image.cpp
@@ -50,6 +50,16 @@ std::string Texture(EmitContext& ctx, IR::TextureInstInfo info,
     }
 }
 
+std::string Image(EmitContext& ctx, IR::TextureInstInfo info,
+                  [[maybe_unused]] const IR::Value& index) {
+    // FIXME: indexed reads
+    if (info.type == TextureType::Buffer) {
+        return fmt::format("image[{}]", ctx.image_buffer_bindings.at(info.descriptor_index));
+    } else {
+        return fmt::format("image[{}]", ctx.image_bindings.at(info.descriptor_index));
+    }
+}
+
 std::string_view TextureType(IR::TextureInstInfo info) {
     if (info.is_depth) {
         switch (info.type) {
@@ -173,6 +183,28 @@ void StoreSparse(EmitContext& ctx, IR::Inst* sparse_inst) {
             sparse_ret, sparse_ret);
     sparse_inst->Invalidate();
 }
+
+std::string_view FormatStorage(ImageFormat format) {
+    switch (format) {
+    case ImageFormat::Typeless:
+        return "U";
+    case ImageFormat::R8_UINT:
+        return "U8";
+    case ImageFormat::R8_SINT:
+        return "S8";
+    case ImageFormat::R16_UINT:
+        return "U16";
+    case ImageFormat::R16_SINT:
+        return "S16";
+    case ImageFormat::R32_UINT:
+        return "U32";
+    case ImageFormat::R32G32_UINT:
+        return "U32X2";
+    case ImageFormat::R32G32B32A32_UINT:
+        return "U32X4";
+    }
+    throw InvalidArgument("Invalid image format {}", format);
+}
 } // Anonymous namespace
 
 void EmitImageSampleImplicitLod(EmitContext& ctx, IR::Inst& inst, const IR::Value& index,
@@ -528,9 +560,16 @@ void EmitImageGradient(EmitContext& ctx, IR::Inst& inst, const IR::Value& index,
     StoreSparse(ctx, sparse_inst);
 }
 
-void EmitImageRead([[maybe_unused]] EmitContext& ctx, [[maybe_unused]] IR::Inst& inst,
-                   [[maybe_unused]] const IR::Value& index, [[maybe_unused]] Register coord) {
-    throw NotImplementedException("GLASM instruction");
+void EmitImageRead(EmitContext& ctx, IR::Inst& inst, const IR::Value& index, Register coord) {
+    const auto info{inst.Flags<IR::TextureInstInfo>()};
+    const auto sparse_inst{inst.GetAssociatedPseudoOperation(IR::Opcode::GetSparseFromOp)};
+    const std::string_view format{FormatStorage(info.image_format)};
+    const std::string_view sparse_mod{sparse_inst ? ".SPARSE" : ""};
+    const std::string_view type{TextureType(info)};
+    const std::string image{Image(ctx, info, index)};
+    const Register ret{ctx.reg_alloc.Define(inst)};
+    ctx.Add("LOADIM.{}{} {},{},{},{};", format, sparse_mod, ret, coord, image, type);
+    StoreSparse(ctx, sparse_inst);
 }
 
 void EmitImageWrite([[maybe_unused]] EmitContext& ctx, [[maybe_unused]] IR::Inst& inst,
-- 
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