[vulkan] add native cubic filtering

src/video_core/host_shaders/convert_abgr8_srgb_to_d24s8.frag

@@ -5,9 +5,10 @@
 
 layout(binding = 0) uniform sampler2D color_texture;
 
-// More accurate sRGB to linear conversion
+// Even more accurate sRGB to linear conversion
+// https://entropymine.com/imageworsener/srgbformula/
 float srgbToLinear(float srgb) {
-    if (srgb <= 0.04045) {
+    if (srgb <= 0.0404482362771082f) { //assumes it's >= 0
         return srgb / 12.92;
     } else {
         return pow((srgb + 0.055) / 1.055, 2.4);

src/video_core/renderer_vulkan/present/filters.cpp

@@ -46,8 +46,12 @@ std::unique_ptr<WindowAdaptPass> MakeBilinear(const Device& device, VkFormat fra
 }
 
 std::unique_ptr<WindowAdaptPass> MakeBicubic(const Device& device, VkFormat frame_format) {
+    // No need for handrolled shader -- if the VK impl can do it for us ;)
+    if (device.IsExtFilterCubicSupported())
+        return std::make_unique<WindowAdaptPass>(device, frame_format, CreateCubicSampler(device),
+                                                 BuildShader(device, VULKAN_PRESENT_FRAG_SPV));
     return std::make_unique<WindowAdaptPass>(device, frame_format, CreateBilinearSampler(device),
-                                             BuildShader(device, PRESENT_BICUBIC_FRAG_SPV));
+                                                BuildShader(device, PRESENT_BICUBIC_FRAG_SPV));
 }
 
 std::unique_ptr<WindowAdaptPass> MakeGaussian(const Device& device, VkFormat frame_format) {

src/video_core/renderer_vulkan/present/util.cpp

@@ -621,6 +621,31 @@ vk::Sampler CreateNearestNeighborSampler(const Device& device) {
     return device.GetLogical().CreateSampler(ci_nn);
 }
 
+vk::Sampler CreateCubicSampler(const Device& device) {
+    const VkSamplerCreateInfo ci_nn{
+        .sType = VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO,
+        .pNext = nullptr,
+        .flags = 0,
+        .magFilter = VK_FILTER_CUBIC_EXT,
+        .minFilter = VK_FILTER_CUBIC_EXT,
+        .mipmapMode = VK_SAMPLER_MIPMAP_MODE_NEAREST,
+        .addressModeU = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER,
+        .addressModeV = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER,
+        .addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER,
+        .mipLodBias = 0.0f,
+        .anisotropyEnable = VK_FALSE,
+        .maxAnisotropy = 0.0f,
+        .compareEnable = VK_FALSE,
+        .compareOp = VK_COMPARE_OP_NEVER,
+        .minLod = 0.0f,
+        .maxLod = 0.0f,
+        .borderColor = VK_BORDER_COLOR_FLOAT_OPAQUE_BLACK,
+        .unnormalizedCoordinates = VK_FALSE,
+    };
+
+    return device.GetLogical().CreateSampler(ci_nn);
+}
+
 void ClearColorImage(vk::CommandBuffer& cmdbuf, VkImage image) {
     static constexpr std::array<VkImageSubresourceRange, 1> subresources{{{
         .aspectMask = VK_IMAGE_ASPECT_COLOR_BIT,

src/video_core/renderer_vulkan/present/util.h

@@ -54,6 +54,7 @@ VkWriteDescriptorSet CreateWriteDescriptorSet(std::vector<VkDescriptorImageInfo>
                                               VkDescriptorSet set, u32 binding);
 vk::Sampler CreateBilinearSampler(const Device& device);
 vk::Sampler CreateNearestNeighborSampler(const Device& device);
+vk::Sampler CreateCubicSampler(const Device& device);
 
 void BeginRenderPass(vk::CommandBuffer& cmdbuf, VkRenderPass render_pass, VkFramebuffer framebuffer,
                      VkExtent2D extent);

src/video_core/vulkan_common/vulkan_device.h

@@ -85,7 +85,8 @@ VK_DEFINE_HANDLE(VmaAllocator)
     EXTENSION(NV, GEOMETRY_SHADER_PASSTHROUGH, geometry_shader_passthrough)                        \
     EXTENSION(NV, VIEWPORT_ARRAY2, viewport_array2)                                                \
     EXTENSION(NV, VIEWPORT_SWIZZLE, viewport_swizzle)                                              \
-    EXTENSION(EXT, DESCRIPTOR_INDEXING, descriptor_indexing)
+    EXTENSION(EXT, DESCRIPTOR_INDEXING, descriptor_indexing)                                       \
+    EXTENSION(EXT, FILTER_CUBIC, filter_cubic)
 
 // Define extensions which must be supported.
 #define FOR_EACH_VK_MANDATORY_EXTENSION(EXTENSION_NAME)                                            \
@@ -549,6 +550,11 @@ public:
         return dynamic_state3_enables;
     }
 
+    /// Returns true if the device supports VK_EXT_filter_cubic
+    bool IsExtFilterCubicSupported() const {
+        return extensions.filter_cubic;
+    }
+
     /// Returns true if the device supports VK_EXT_line_rasterization.
     bool IsExtLineRasterizationSupported() const {
         return extensions.line_rasterization;