account for max viewport limit, add todo for ViewportIndex

src/shader_recompiler/backend/spirv/emit_spirv_special.cpp

@@ -47,14 +47,14 @@ void ConvertPositionToClipSpace(EmitContext& ctx) {
                                           ctx.push_data_block,
                                           ctx.ConstU32(PushData::YScaleIndex))};
     const Id yscale{ctx.OpLoad(type, yscale_ptr)};
-    Id ndc_x = ctx.OpFMul(type, x, xscale);
+    const Id vport_w =
-    ndc_x = ctx.OpFAdd(type, ndc_x, xoffset);
+        ctx.Constant(type, float(std::min<u32>(ctx.profile.max_viewport_width / 2, 8_KB)));
-    ndc_x = ctx.OpFDiv(type, ndc_x, ctx.Constant(type, float(8_KB)));
+    const Id wnd_x = ctx.OpFAdd(type, ctx.OpFMul(type, x, xscale), xoffset);
-    ndc_x = ctx.OpFSub(type, ndc_x, ctx.Constant(type, 1.f));
+    const Id ndc_x = ctx.OpFSub(type, ctx.OpFDiv(type, wnd_x, vport_w), ctx.Constant(type, 1.f));
-    Id ndc_y = ctx.OpFMul(type, y, yscale);
+    const Id vport_h =
-    ndc_y = ctx.OpFAdd(type, ndc_y, yoffset);
+        ctx.Constant(type, float(std::min<u32>(ctx.profile.max_viewport_height / 2, 8_KB)));
-    ndc_y = ctx.OpFDiv(type, ndc_y, ctx.Constant(type, float(8_KB)));
+    const Id wnd_y = ctx.OpFAdd(type, ctx.OpFMul(type, y, yscale), yoffset);
-    ndc_y = ctx.OpFSub(type, ndc_y, ctx.Constant(type, 1.f));
+    const Id ndc_y = ctx.OpFSub(type, ctx.OpFDiv(type, wnd_y, vport_h), ctx.Constant(type, 1.f));
     const Id vector{ctx.OpCompositeConstruct(ctx.F32[4], std::array<Id, 4>({ndc_x, ndc_y, z, w}))};
     ctx.OpStore(ctx.output_position, vector);
 }

src/shader_recompiler/profile.h

@@ -30,6 +30,8 @@ struct Profile {
     bool needs_manual_interpolation{};
     bool needs_lds_barriers{};
     u64 min_ssbo_alignment{};
+    u32 max_viewport_width{};
+    u32 max_viewport_height{};
 };
 
 } // namespace Shader

src/video_core/renderer_vulkan/vk_instance.h

@@ -274,6 +274,14 @@ public:
         return min_imported_host_pointer_alignment;
     }
 
+    u32 GetMaxViewportWidth() const {
+        return properties.limits.maxViewportDimensions[0];
+    }
+
+    u32 GetMaxViewportHeight() const {
+        return properties.limits.maxViewportDimensions[1];
+    }
+
     /// Returns the sample count flags supported by framebuffers.
     vk::SampleCountFlags GetFramebufferSampleCounts() const {
         return properties.limits.framebufferColorSampleCounts &

src/video_core/renderer_vulkan/vk_pipeline_cache.cpp

@@ -210,6 +210,8 @@ PipelineCache::PipelineCache(const Instance& instance_, Scheduler& scheduler_,
                                       instance.GetDriverID() == vk::DriverId::eNvidiaProprietary,
         .needs_lds_barriers = instance.GetDriverID() == vk::DriverId::eNvidiaProprietary ||
                               instance.GetDriverID() == vk::DriverId::eMoltenvk,
+        .max_viewport_width = instance.GetMaxViewportWidth(),
+        .max_viewport_height = instance.GetMaxViewportHeight(),
     };
     auto [cache_result, cache] = instance.GetDevice().createPipelineCacheUnique({});
     ASSERT_MSG(cache_result == vk::Result::eSuccess, "Failed to create pipeline cache: {}",

src/video_core/renderer_vulkan/vk_rasterizer.cpp

@@ -504,10 +504,17 @@ bool Rasterizer::BindResources(const Pipeline* pipeline) {
         }
         push_data.step0 = regs.vgt_instance_step_rate_0;
         push_data.step1 = regs.vgt_instance_step_rate_1;
-        push_data.xoffset = regs.viewport_control.xoffset_enable ? regs.viewports[0].xoffset : 0.f;
+
-        push_data.xscale = regs.viewport_control.xscale_enable ? regs.viewports[0].xscale : 1.f;
+        // TODO(roamic): add support for multiple viewports and geometry shaders when ViewportIndex
-        push_data.yoffset = regs.viewport_control.yoffset_enable ? regs.viewports[0].yoffset : 0.f;
+        // is encountered and implemented in the recompiler.
-        push_data.yscale = regs.viewport_control.yscale_enable ? regs.viewports[0].yscale : 1.f;
+        if (stage->stage == Shader::Stage::Vertex) {
+            push_data.xoffset =
+                regs.viewport_control.xoffset_enable ? regs.viewports[0].xoffset : 0.f;
+            push_data.xscale = regs.viewport_control.xscale_enable ? regs.viewports[0].xscale : 1.f;
+            push_data.yoffset =
+                regs.viewport_control.yoffset_enable ? regs.viewports[0].yoffset : 0.f;
+            push_data.yscale = regs.viewport_control.yscale_enable ? regs.viewports[0].yscale : 1.f;
+        }
         stage->PushUd(binding, push_data);
 
         BindBuffers(*stage, binding, push_data, set_writes, buffer_barriers);
@@ -1174,8 +1181,8 @@ void Rasterizer::UpdateViewportScissorState(const GraphicsPipeline& pipeline) {
             viewports.push_back({
                 .x = 0.f,
                 .y = 0.f,
-                .width = float(16_KB),
+                .width = float(std::min<u32>(instance.GetMaxViewportWidth(), 16_KB)),
-                .height = float(16_KB),
+                .height = float(std::min<u32>(instance.GetMaxViewportHeight(), 16_KB)),
                 .minDepth = 0.0,
                 .maxDepth = 1.0,
             });