Metal: Make GLSL shader source MSL compliant also

Metal shading language follows the C++ 14 standard and in some cases requires a greater level of explicitness than GLSL. There are also some small language differences:

- Explicit type-casts (C++ requirements)
- Explicit constant values (C++ requirements, e.g. floating point values using 0.0 instead of 0).
- Metal/OpenGL compatibility paths
- GLSL Function prototypes
- Explicit accessors for vector types when sampling textures.

Authored by Apple: Michael Parkin-White

Ref T96261

Reviewed By: fclem

Maniphest Tasks: T96261

Differential Revision: https://developer.blender.org/D14378

4 files changed, 8 insertions, 8 deletions

diff --git a/source/blender/draw/intern/shaders/common_hair_lib.glsl b/source/blender/draw/intern/shaders/common_hair_lib.glsl
index ed8b8aeb849..7f94b7ea1c1 100644
--- a/source/blender/draw/intern/shaders/common_hair_lib.glsl
+++ b/source/blender/draw/intern/shaders/common_hair_lib.glsl
@@ -158,7 +158,7 @@ float hair_shaperadius(float shape, float root, float tip, float time)
   return (radius * (root - tip)) + tip;
 }
 
-#  ifdef OS_MAC
+#  if defined(OS_MAC) && defined(GPU_OPENGL)
 in float dummy;
 #  endif
 
@@ -178,7 +178,7 @@ void hair_get_pos_tan_binor_time(bool is_persp,
   wpos = data.point_position;
   time = data.point_time;
 
-#  ifdef OS_MAC
+#  if defined(OS_MAC) && defined(GPU_OPENGL)
   /* Generate a dummy read to avoid the driver bug with shaders having no
    * vertex reads on macOS (T60171) */
   wpos.y += dummy * 0.0;
diff --git a/source/blender/draw/intern/shaders/common_math_geom_lib.glsl b/source/blender/draw/intern/shaders/common_math_geom_lib.glsl
index 7b701d1d81b..6d4452c18c8 100644
--- a/source/blender/draw/intern/shaders/common_math_geom_lib.glsl
+++ b/source/blender/draw/intern/shaders/common_math_geom_lib.glsl
@@ -86,7 +86,7 @@ float line_unit_box_intersect_dist(vec3 lineorigin, vec3 linedirection)
 float line_unit_box_intersect_dist_safe(vec3 lineorigin, vec3 linedirection)
 {
   vec3 safe_linedirection = max(vec3(1e-8), abs(linedirection)) *
-                            mix(vec3(1.0), -vec3(1.0), lessThan(linedirection, vec3(0.0)));
+                            select(vec3(1.0), -vec3(1.0), lessThan(linedirection, vec3(0.0)));
   return line_unit_box_intersect_dist(lineorigin, safe_linedirection);
 }
 
diff --git a/source/blender/draw/intern/shaders/common_math_lib.glsl b/source/blender/draw/intern/shaders/common_math_lib.glsl
index 1701056cbb7..4d0ffaeb40f 100644
--- a/source/blender/draw/intern/shaders/common_math_lib.glsl
+++ b/source/blender/draw/intern/shaders/common_math_lib.glsl
@@ -84,9 +84,9 @@ float avg(vec3 v) { return dot(vec3(1.0 / 3.0), v); }
 float avg(vec4 v) { return dot(vec4(1.0 / 4.0), v); }
 
 float safe_rcp(float a) { return (a != 0.0) ? (1.0 / a) : 0.0; }
-vec2 safe_rcp(vec2 a) { return mix(vec2(0.0), (1.0 / a), notEqual(a, vec2(0.0))); }
-vec3 safe_rcp(vec3 a) { return mix(vec3(0.0), (1.0 / a), notEqual(a, vec3(0.0))); }
-vec4 safe_rcp(vec4 a) { return mix(vec4(0.0), (1.0 / a), notEqual(a, vec4(0.0))); }
+vec2 safe_rcp(vec2 a) { return select(vec2(0.0), (1.0 / a), notEqual(a, vec2(0.0))); }
+vec3 safe_rcp(vec3 a) { return select(vec3(0.0), (1.0 / a), notEqual(a, vec3(0.0))); }
+vec4 safe_rcp(vec4 a) { return select(vec4(0.0), (1.0 / a), notEqual(a, vec4(0.0))); }
 
 float safe_sqrt(float a) { return sqrt(max(a, 0.0)); }
 
diff --git a/source/blender/draw/intern/shaders/common_view_lib.glsl b/source/blender/draw/intern/shaders/common_view_lib.glsl
index 2ac157ad208..6c58752c8bb 100644
--- a/source/blender/draw/intern/shaders/common_view_lib.glsl
+++ b/source/blender/draw/intern/shaders/common_view_lib.glsl
@@ -174,7 +174,7 @@ flat in int resourceIDFrag;
 
 /* Breaking this across multiple lines causes issues for some older GLSL compilers. */
 /* clang-format off */
-#if !defined(GPU_INTEL) && !defined(GPU_DEPRECATED_AMD_DRIVER) && !defined(OS_MAC) && !defined(INSTANCED_ATTR) && !defined(DRW_LEGACY_MODEL_MATRIX)
+#if !defined(GPU_INTEL) && !defined(GPU_DEPRECATED_AMD_DRIVER) && (!defined(OS_MAC) || defined(GPU_METAL)) && !defined(INSTANCED_ATTR) && !defined(DRW_LEGACY_MODEL_MATRIX)
 /* clang-format on */
 
 /* Temporary until we fully make the switch. */
@@ -251,7 +251,7 @@ uniform mat4 ModelMatrixInverse;
 
 /* Due to some shader compiler bug, we somewhat need to access gl_VertexID
  * to make vertex shaders work. even if it's actually dead code. */
-#ifdef GPU_INTEL
+#if defined(GPU_INTEL) && defined(GPU_OPENGL)
 #  define GPU_INTEL_VERTEX_SHADER_WORKAROUND gl_Position.x = float(gl_VertexID);
 #else
 #  define GPU_INTEL_VERTEX_SHADER_WORKAROUND