opengl: Declare fragment outputs even if they are not used

Fixes Ori and the Blind Forest's menu on GLASM. For some reason
(probably high level optimizations) it is not sanitized on SPIR-V for
OpenGL. Vulkan is unaffected by this change.

6 files changed, 18 insertions, 10 deletions

diff --git a/src/shader_recompiler/backend/glasm/emit_context.cpp b/src/shader_recompiler/backend/glasm/emit_context.cpp
index e18526816..08918a5c2 100644
--- a/src/shader_recompiler/backend/glasm/emit_context.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_context.cpp
@@ -117,13 +117,9 @@ EmitContext::EmitContext(IR::Program& program, Bindings& bindings, const Profile
                 index, index);
         }
     }
-    for (size_t index = 0; index < info.stores_frag_color.size(); ++index) {
-        if (!info.stores_frag_color[index]) {
-            continue;
-        }
-        if (index == 0) {
-            Add("OUTPUT frag_color0=result.color;");
-        } else {
+    if (stage == Stage::Fragment) {
+        Add("OUTPUT frag_color0=result.color;");
+        for (size_t index = 1; index < info.stores_frag_color.size(); ++index) {
             Add("OUTPUT frag_color{}=result.color[{}];", index, index);
         }
     }
diff --git a/src/shader_recompiler/backend/glasm/emit_glasm.cpp b/src/shader_recompiler/backend/glasm/emit_glasm.cpp
index e23208d2c..70ca6f621 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_glasm.cpp
@@ -298,8 +298,7 @@ void SetupOptions(const IR::Program& program, const Profile& profile,
     if (stage == Stage::Fragment && runtime_info.force_early_z != 0) {
         header += "OPTION NV_early_fragment_tests;";
     }
-    const auto non_zero_frag_colors{info.stores_frag_color | std::views::drop(1)};
-    if (std::ranges::find(non_zero_frag_colors, true) != non_zero_frag_colors.end()) {
+    if (stage == Stage::Fragment) {
         header += "OPTION ARB_draw_buffers;";
     }
 }
diff --git a/src/shader_recompiler/backend/spirv/emit_context.cpp b/src/shader_recompiler/backend/spirv/emit_context.cpp
index 3e8899f53..7c618125e 100644
--- a/src/shader_recompiler/backend/spirv/emit_context.cpp
+++ b/src/shader_recompiler/backend/spirv/emit_context.cpp
@@ -1320,7 +1320,7 @@ void EmitContext::DefineOutputs(const IR::Program& program) {
         break;
     case Stage::Fragment:
         for (u32 index = 0; index < 8; ++index) {
-            if (!info.stores_frag_color[index]) {
+            if (!info.stores_frag_color[index] && !profile.need_declared_frag_colors) {
                 continue;
             }
             frag_color[index] = DefineOutput(*this, F32[4], std::nullopt);
diff --git a/src/shader_recompiler/profile.h b/src/shader_recompiler/profile.h
index f8913bf14..f059e3b26 100644
--- a/src/shader_recompiler/profile.h
+++ b/src/shader_recompiler/profile.h
@@ -84,7 +84,11 @@ struct Profile {
     bool support_int64_atomics{};
 
     bool warp_size_potentially_larger_than_guest{};
+
     bool lower_left_origin_mode{};
+    /// Fragment outputs have to be declared even if they are not written to avoid undefined values.
+    /// See Ori and the Blind Forest's main menu for reference.
+    bool need_declared_frag_colors{};
 
     /// OpFClamp is broken and OpFMax + OpFMin should be used instead
     bool has_broken_spirv_clamp{};
diff --git a/src/video_core/renderer_opengl/gl_shader_cache.cpp b/src/video_core/renderer_opengl/gl_shader_cache.cpp
index 7d2ec4efa..6ea7c0ee8 100644
--- a/src/video_core/renderer_opengl/gl_shader_cache.cpp
+++ b/src/video_core/renderer_opengl/gl_shader_cache.cpp
@@ -276,7 +276,9 @@ ShaderCache::ShaderCache(RasterizerOpenGL& rasterizer_, Core::Frontend::EmuWindo
         .support_int64_atomics = false,
 
         .warp_size_potentially_larger_than_guest = true,
+
         .lower_left_origin_mode = true,
+        .need_declared_frag_colors = true,
 
         .has_broken_spirv_clamp = true,
         .has_broken_unsigned_image_offsets = true,
diff --git a/src/video_core/renderer_vulkan/vk_pipeline_cache.cpp b/src/video_core/renderer_vulkan/vk_pipeline_cache.cpp
index b6998e37c..cec51cc77 100644
--- a/src/video_core/renderer_vulkan/vk_pipeline_cache.cpp
+++ b/src/video_core/renderer_vulkan/vk_pipeline_cache.cpp
@@ -274,9 +274,16 @@ PipelineCache::PipelineCache(RasterizerVulkan& rasterizer_, Tegra::Engines::Maxw
         .support_typeless_image_loads = device.IsFormatlessImageLoadSupported(),
         .support_demote_to_helper_invocation = true,
         .support_int64_atomics = device.IsExtShaderAtomicInt64Supported(),
+
         .warp_size_potentially_larger_than_guest = device.IsWarpSizePotentiallyBiggerThanGuest(),
+
+        .lower_left_origin_mode = false,
+        .need_declared_frag_colors = false,
+
         .has_broken_spirv_clamp = driver_id == VK_DRIVER_ID_INTEL_PROPRIETARY_WINDOWS_KHR,
         .has_broken_unsigned_image_offsets = false,
+        .has_broken_signed_operations = false,
+        .ignore_nan_fp_comparisons = false,
     };
 }