Henri Verbeet : vkd3d-shader/spirv: Allow the origin of fragment coordinates to be specified.

[Alexandre Julliard]

Module: vkd3d
Branch: master
Commit: e7eec3e023bf669fc9a632d4390db549a2de2718
URL:    https://gitlab.winehq.org/wine/vkd3d/-/commit/e7eec3e023bf669fc9a632d4390db5...

Author: Henri Verbeet <hverbeet(a)codeweavers.com>
Date:   Sat Oct 14 18:07:38 2023 +0200

vkd3d-shader/spirv: Allow the origin of fragment coordinates to be specified.

We typically want to use lower-left in OpenGL environments when rendering to
FBOs.

---

 include/vkd3d_shader.h    | 25 +++++++++++++++++++++++++
 libs/vkd3d-shader/spirv.c | 13 ++++++++++++-
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/include/vkd3d_shader.h b/include/vkd3d_shader.h
index 94f79c7c..1d6cbbf8 100644
--- a/include/vkd3d_shader.h
+++ b/include/vkd3d_shader.h
@@ -173,6 +173,21 @@ enum vkd3d_shader_compile_option_backward_compatibility
     VKD3D_FORCE_32_BIT_ENUM(VKD3D_SHADER_COMPILE_OPTION_BACKWARD_COMPATIBILITY),
 };
 
+/**
+ * Determines the origin of fragment coordinates.
+ *
+ * \since 1.10
+ */
+enum vkd3d_shader_compile_option_fragment_coordinate_origin
+{
+    /** Fragment coordinates originate from the upper-left. This is the
+     * default; it's also the only value supported by Vulkan environments. */
+    VKD3D_SHADER_COMPILE_OPTION_FRAGMENT_COORDINATE_ORIGIN_UPPER_LEFT = 0x00000000,
+    /** Fragment coordinates originate from the lower-left. This matches the
+     * traditional behaviour of OpenGL environments. */
+    VKD3D_SHADER_COMPILE_OPTION_FRAGMENT_COORDINATE_ORIGIN_LOWER_LEFT = 0x00000001,
+};
+
 enum vkd3d_shader_compile_option_name
 {
     /**
@@ -220,6 +235,16 @@ enum vkd3d_shader_compile_option_name
      * \since 1.10
      */
     VKD3D_SHADER_COMPILE_OPTION_BACKWARD_COMPATIBILITY = 0x00000008,
+    /**
+     * This option specifies the origin of fragment coordinates for SPIR-V
+     * targets.
+     *
+     * \a value is a member of enum
+     * vkd3d_shader_compile_option_fragment_coordinate_origin.
+     *
+     * \since 1.10
+     */
+    VKD3D_SHADER_COMPILE_OPTION_FRAGMENT_COORDINATE_ORIGIN = 0x00000009,
 
     VKD3D_FORCE_32_BIT_ENUM(VKD3D_SHADER_COMPILE_OPTION_NAME),
 };
diff --git a/libs/vkd3d-shader/spirv.c b/libs/vkd3d-shader/spirv.c
index 61d75757..c681b9f8 100644
--- a/libs/vkd3d-shader/spirv.c
+++ b/libs/vkd3d-shader/spirv.c
@@ -2288,6 +2288,7 @@ struct spirv_compiler
     bool strip_debug;
     bool ssbo_uavs;
     bool uav_read_without_format;
+    SpvExecutionMode fragment_coordinate_origin;
 
     struct rb_tree symbol_table;
     uint32_t temp_id;
@@ -2453,6 +2454,7 @@ static struct spirv_compiler *spirv_compiler_create(const struct vkd3d_shader_ve
     compiler->formatting = VKD3D_SHADER_COMPILE_OPTION_FORMATTING_INDENT
             | VKD3D_SHADER_COMPILE_OPTION_FORMATTING_HEADER;
     compiler->write_tess_geom_point_size = true;
+    compiler->fragment_coordinate_origin = SpvExecutionModeOriginUpperLeft;
 
     for (i = 0; i < compile_info->option_count; ++i)
     {
@@ -2493,6 +2495,15 @@ static struct spirv_compiler *spirv_compiler_create(const struct vkd3d_shader_ve
                 compiler->write_tess_geom_point_size = option->value;
                 break;
 
+            case VKD3D_SHADER_COMPILE_OPTION_FRAGMENT_COORDINATE_ORIGIN:
+                if (option->value == VKD3D_SHADER_COMPILE_OPTION_FRAGMENT_COORDINATE_ORIGIN_UPPER_LEFT)
+                    compiler->fragment_coordinate_origin = SpvExecutionModeOriginUpperLeft;
+                else if (option->value == VKD3D_SHADER_COMPILE_OPTION_FRAGMENT_COORDINATE_ORIGIN_LOWER_LEFT)
+                    compiler->fragment_coordinate_origin = SpvExecutionModeOriginLowerLeft;
+                else
+                    WARN("Ignoring unrecognised value %#x for option %#x.\n", option->value, option->name);
+                break;
+
             default:
                 WARN("Ignoring unrecognised option %#x with value %#x.\n", option->name, option->value);
                 break;
@@ -5358,7 +5369,7 @@ static void spirv_compiler_emit_initial_declarations(struct spirv_compiler *comp
             break;
         case VKD3D_SHADER_TYPE_PIXEL:
             vkd3d_spirv_set_execution_model(builder, SpvExecutionModelFragment);
-            spirv_compiler_emit_execution_mode(compiler, SpvExecutionModeOriginUpperLeft, NULL, 0);
+            spirv_compiler_emit_execution_mode(compiler, compiler->fragment_coordinate_origin, NULL, 0);
             break;
         case VKD3D_SHADER_TYPE_COMPUTE:
             vkd3d_spirv_set_execution_model(builder, SpvExecutionModelGLCompute);