shader/image: Implement SULD and remove irrelevant code

* Implement SULD as float.
* Remove conditional declaration of GL_ARB_shader_viewport_layer_array.

src/video_core/renderer_opengl/gl_device.cpp

@@ -2,8 +2,10 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <algorithm>
 #include <array>
 #include <cstddef>
+#include <vector>
 #include <glad/glad.h>
 
 #include "common/logging/log.h"
@@ -30,9 +32,27 @@ bool TestProgram(const GLchar* glsl) {
     return link_status == GL_TRUE;
 }
 
+std::vector<std::string_view> GetExtensions() {
+    GLint num_extensions;
+    glGetIntegerv(GL_NUM_EXTENSIONS, &num_extensions);
+    std::vector<std::string_view> extensions;
+    extensions.reserve(num_extensions);
+    for (GLint index = 0; index < num_extensions; ++index) {
+        extensions.push_back(
+            reinterpret_cast<const char*>(glGetStringi(GL_EXTENSIONS, static_cast<GLuint>(index))));
+    }
+    return extensions;
+}
+
+bool HasExtension(const std::vector<std::string_view>& images, std::string_view extension) {
+    return std::find(images.begin(), images.end(), extension) != images.end();
+}
+
 } // Anonymous namespace
 
 Device::Device() {
+    const std::vector extensions = GetExtensions();
+
     uniform_buffer_alignment = GetInteger<std::size_t>(GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT);
     shader_storage_alignment = GetInteger<std::size_t>(GL_SHADER_STORAGE_BUFFER_OFFSET_ALIGNMENT);
     max_vertex_attributes = GetInteger<u32>(GL_MAX_VERTEX_ATTRIBS);
@@ -40,6 +60,7 @@ Device::Device() {
     has_warp_intrinsics = GLAD_GL_NV_gpu_shader5 && GLAD_GL_NV_shader_thread_group &&
                           GLAD_GL_NV_shader_thread_shuffle;
     has_vertex_viewport_layer = GLAD_GL_ARB_shader_viewport_layer_array;
+    has_image_load_formatted = HasExtension(extensions, "GL_EXT_shader_image_load_formatted");
     has_variable_aoffi = TestVariableAoffi();
     has_component_indexing_bug = TestComponentIndexingBug();
     has_precise_bug = TestPreciseBug();
@@ -55,6 +76,7 @@ Device::Device(std::nullptr_t) {
     max_varyings = 15;
     has_warp_intrinsics = true;
     has_vertex_viewport_layer = true;
+    has_image_load_formatted = true;
     has_variable_aoffi = true;
     has_component_indexing_bug = false;
     has_precise_bug = false;

src/video_core/renderer_opengl/gl_device.h

@@ -38,6 +38,10 @@ public:
         return has_vertex_viewport_layer;
     }
 
+    bool HasImageLoadFormatted() const {
+        return has_image_load_formatted;
+    }
+
     bool HasVariableAoffi() const {
         return has_variable_aoffi;
     }
@@ -61,6 +65,7 @@ private:
     u32 max_varyings{};
     bool has_warp_intrinsics{};
     bool has_vertex_viewport_layer{};
+    bool has_image_load_formatted{};
     bool has_variable_aoffi{};
     bool has_component_indexing_bug{};
     bool has_precise_bug{};

src/video_core/renderer_opengl/gl_shader_cache.cpp

@@ -211,14 +211,14 @@ CachedProgram SpecializeShader(const std::string& code, const GLShader::ShaderEn
     const auto primitive_mode{variant.primitive_mode};
     const auto texture_buffer_usage{variant.texture_buffer_usage};
 
-    std::string source = "#version 430 core\n"
-                         "#extension GL_ARB_separate_shader_objects : enable\n"
-                         "#extension GL_NV_gpu_shader5 : enable\n"
-                         "#extension GL_NV_shader_thread_group : enable\n"
-                         "#extension GL_NV_shader_thread_shuffle : enable\n";
-    if (entries.shader_viewport_layer_array) {
-        source += "#extension GL_ARB_shader_viewport_layer_array : enable\n";
-    }
+    std::string source = R"(#version 430 core
+#extension GL_ARB_separate_shader_objects : enable
+#extension GL_ARB_shader_viewport_layer_array : enable
+#extension GL_EXT_shader_image_load_formatted : enable
+#extension GL_NV_gpu_shader5 : enable
+#extension GL_NV_shader_thread_group : enable
+#extension GL_NV_shader_thread_shuffle : enable
+)";
     if (program_type == ProgramType::Compute) {
         source += "#extension GL_ARB_compute_variable_group_size : require\n";
     }

src/video_core/renderer_opengl/gl_shader_decompiler.cpp

@@ -19,6 +19,7 @@
 #include "video_core/renderer_opengl/gl_device.h"
 #include "video_core/renderer_opengl/gl_rasterizer.h"
 #include "video_core/renderer_opengl/gl_shader_decompiler.h"
+#include "video_core/shader/node.h"
 #include "video_core/shader/shader_ir.h"
 
 namespace OpenGL::GLShader {
@@ -398,8 +399,6 @@ public:
                                                        usage.is_read, usage.is_written);
         }
         entries.clip_distances = ir.GetClipDistances();
-        entries.shader_viewport_layer_array =
-            IsVertexShader(stage) && (ir.UsesLayer() || ir.UsesViewportIndex());
         entries.shader_length = ir.GetLength();
         return entries;
     }
@@ -1801,6 +1800,19 @@ private:
         return {tmp, Type::Float};
     }
 
+    Expression ImageLoad(Operation operation) {
+        if (!device.HasImageLoadFormatted()) {
+            LOG_ERROR(Render_OpenGL,
+                      "Device lacks GL_EXT_shader_image_load_formatted, stubbing image load");
+            return {"0", Type::Int};
+        }
+
+        const auto meta{std::get<MetaImage>(operation.GetMeta())};
+        return {fmt::format("imageLoad({}, {}){}", GetImage(meta.image),
+                            BuildIntegerCoordinates(operation), GetSwizzle(meta.element)),
+                Type::Float};
+    }
+
     Expression ImageStore(Operation operation) {
         const auto meta{std::get<MetaImage>(operation.GetMeta())};
         code.AddLine("imageStore({}, {}, {});", GetImage(meta.image),
@@ -2164,6 +2176,7 @@ private:
         &GLSLDecompiler::TextureQueryLod,
         &GLSLDecompiler::TexelFetch,
 
+        &GLSLDecompiler::ImageLoad,
         &GLSLDecompiler::ImageStore,
         &GLSLDecompiler::AtomicImageAdd,
         &GLSLDecompiler::AtomicImageMin,

src/video_core/renderer_opengl/gl_shader_decompiler.h

@@ -90,7 +90,6 @@ struct ShaderEntries {
     std::vector<ImageEntry> images;
     std::vector<GlobalMemoryEntry> global_memory_entries;
     std::array<bool, Maxwell::NumClipDistances> clip_distances{};
-    bool shader_viewport_layer_array{};
     std::size_t shader_length{};
 };
 

src/video_core/renderer_opengl/gl_shader_disk_cache.cpp

@@ -382,12 +382,6 @@ std::optional<ShaderDiskCacheDecompiled> ShaderDiskCacheOpenGL::LoadDecompiledEn
         }
     }
 
-    bool shader_viewport_layer_array{};
-    if (!LoadObjectFromPrecompiled(shader_viewport_layer_array)) {
-        return {};
-    }
-    entry.entries.shader_viewport_layer_array = shader_viewport_layer_array;
-
     u64 shader_length{};
     if (!LoadObjectFromPrecompiled(shader_length)) {
         return {};
@@ -464,10 +458,6 @@ bool ShaderDiskCacheOpenGL::SaveDecompiledFile(u64 unique_identifier, const std:
         }
     }
 
-    if (!SaveObjectToPrecompiled(entries.shader_viewport_layer_array)) {
-        return false;
-    }
-
     if (!SaveObjectToPrecompiled(static_cast<u64>(entries.shader_length))) {
         return false;
     }