texture_cache: Implement depth stencil texture swizzles

Stop ignoring image swizzles on depth and stencil images.

This doesn't fix a known issue on Xenoblade Chronicles 2 where an OpenGL
texture changes swizzles twice before being used. A proper fix would be
having a small texture view cache for this like we do on Vulkan.

2 files changed, 29 insertions, 20 deletions

diff --git a/src/video_core/renderer_opengl/gl_texture_cache.cpp b/src/video_core/renderer_opengl/gl_texture_cache.cpp
index 94fbd2a22..7e0ffe3cd 100644
--- a/src/video_core/renderer_opengl/gl_texture_cache.cpp
+++ b/src/video_core/renderer_opengl/gl_texture_cache.cpp
@@ -238,6 +238,12 @@ OGLTexture CreateTexture(const SurfaceParams& params, GLenum target, GLenum inte
     return texture;
 }
 
+constexpr u32 EncodeSwizzle(SwizzleSource x_source, SwizzleSource y_source, SwizzleSource z_source,
+                            SwizzleSource w_source) {
+    return (static_cast<u32>(x_source) << 24) | (static_cast<u32>(y_source) << 16) |
+           (static_cast<u32>(z_source) << 8) | static_cast<u32>(w_source);
+}
+
 } // Anonymous namespace
 
 CachedSurface::CachedSurface(const GPUVAddr gpu_addr, const SurfaceParams& params,
@@ -404,7 +410,8 @@ CachedSurfaceView::CachedSurfaceView(CachedSurface& surface, const ViewParams& p
     if (!is_proxy) {
         texture_view = CreateTextureView();
     }
-    swizzle = EncodeSwizzle(SwizzleSource::R, SwizzleSource::G, SwizzleSource::B, SwizzleSource::A);
+    current_swizzle =
+        EncodeSwizzle(SwizzleSource::R, SwizzleSource::G, SwizzleSource::B, SwizzleSource::A);
 }
 
 CachedSurfaceView::~CachedSurfaceView() = default;
@@ -449,25 +456,35 @@ void CachedSurfaceView::Attach(GLenum attachment, GLenum target) const {
 
 void CachedSurfaceView::ApplySwizzle(SwizzleSource x_source, SwizzleSource y_source,
                                      SwizzleSource z_source, SwizzleSource w_source) {
-    u32 new_swizzle = EncodeSwizzle(x_source, y_source, z_source, w_source);
-    if (new_swizzle == swizzle)
+    const u32 new_swizzle = EncodeSwizzle(x_source, y_source, z_source, w_source);
+    if (current_swizzle == new_swizzle) {
         return;
-    swizzle = new_swizzle;
-    const std::array gl_swizzle = {GetSwizzleSource(x_source), GetSwizzleSource(y_source),
-                                   GetSwizzleSource(z_source), GetSwizzleSource(w_source)};
+    }
+    current_swizzle = new_swizzle;
+
+    std::array swizzle{x_source, y_source, z_source, w_source};
+
     const GLuint handle = GetTexture();
-    const PixelFormat format = surface.GetSurfaceParams().pixel_format;
-    switch (format) {
+    switch (const PixelFormat format = surface.GetSurfaceParams().pixel_format) {
+    case PixelFormat::S8Z24:
     case PixelFormat::Z24S8:
     case PixelFormat::Z32FS8:
-    case PixelFormat::S8Z24:
+        UNIMPLEMENTED_IF(x_source != SwizzleSource::R && x_source != SwizzleSource::G);
         glTextureParameteri(handle, GL_DEPTH_STENCIL_TEXTURE_MODE,
                             GetComponent(format, x_source == SwizzleSource::R));
-        break;
-    default:
+
+        // Make sure we sample the first component
+        std::transform(swizzle.begin(), swizzle.end(), swizzle.begin(), [](SwizzleSource value) {
+            return value == SwizzleSource::G ? SwizzleSource::R : value;
+        });
+        [[fallthrough]];
+    default: {
+        const std::array gl_swizzle = {GetSwizzleSource(swizzle[0]), GetSwizzleSource(swizzle[1]),
+                                       GetSwizzleSource(swizzle[2]), GetSwizzleSource(swizzle[3])};
         glTextureParameteriv(handle, GL_TEXTURE_SWIZZLE_RGBA, gl_swizzle.data());
         break;
     }
+    }
 }
 
 OGLTextureView CachedSurfaceView::CreateTextureView() const {
diff --git a/src/video_core/renderer_opengl/gl_texture_cache.h b/src/video_core/renderer_opengl/gl_texture_cache.h
index 02d9981a1..0d88d738f 100644
--- a/src/video_core/renderer_opengl/gl_texture_cache.h
+++ b/src/video_core/renderer_opengl/gl_texture_cache.h
@@ -110,14 +110,6 @@ public:
     }
 
 private:
-    u32 EncodeSwizzle(Tegra::Texture::SwizzleSource x_source,
-                      Tegra::Texture::SwizzleSource y_source,
-                      Tegra::Texture::SwizzleSource z_source,
-                      Tegra::Texture::SwizzleSource w_source) const {
-        return (static_cast<u32>(x_source) << 24) | (static_cast<u32>(y_source) << 16) |
-               (static_cast<u32>(z_source) << 8) | static_cast<u32>(w_source);
-    }
-
     OGLTextureView CreateTextureView() const;
 
     CachedSurface& surface;
@@ -125,7 +117,7 @@ private:
     GLenum format{};
 
     OGLTextureView texture_view;
-    u32 swizzle{};
+    u32 current_swizzle{};
     bool is_proxy{};
 };