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

9 files changed, 57 insertions, 13 deletions

diff --git a/source/blender/gpu/shaders/gpu_shader_2D_image_multi_rect_vert.glsl b/source/blender/gpu/shaders/gpu_shader_2D_image_multi_rect_vert.glsl
index 9851e08fe2e..353bf1481da 100644
--- a/source/blender/gpu/shaders/gpu_shader_2D_image_multi_rect_vert.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_2D_image_multi_rect_vert.glsl
@@ -23,15 +23,15 @@ void main()
 
   /* Use pos to select the right swizzle (instead of gl_VertexID)
    * in order to workaround an OSX driver bug. */
-  if (pos == vec2(0.0, 0.0)) {
+  if (all(equal(pos, vec2(0.0, 0.0)))) {
     rect.xy = rect.xz;
     tex.xy = tex.xz;
   }
-  else if (pos == vec2(0.0, 1.0)) {
+  else if (all(equal(pos, vec2(0.0, 1.0)))) {
     rect.xy = rect.xw;
     tex.xy = tex.xw;
   }
-  else if (pos == vec2(1.0, 1.0)) {
+  else if (all(equal(pos, vec2(1.0, 1.0)))) {
     rect.xy = rect.yw;
     tex.xy = tex.yw;
   }
diff --git a/source/blender/gpu/shaders/gpu_shader_2D_image_rect_vert.glsl b/source/blender/gpu/shaders/gpu_shader_2D_image_rect_vert.glsl
index d9a5aeeef46..903c602c5d6 100644
--- a/source/blender/gpu/shaders/gpu_shader_2D_image_rect_vert.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_2D_image_rect_vert.glsl
@@ -15,6 +15,32 @@ void main()
 {
   vec2 uv;
   vec2 co;
+
+#ifdef GPU_METAL
+/* Metal API does not support Triangle fan primitive topology.
+ * When this shader is called using Triangle-Strip, vertex ID's
+ * are in a different order. */
+#  define GPU_PRIM_TRI_STRIP
+#endif
+
+#ifdef GPU_PRIM_TRI_STRIP
+  if (gl_VertexID == 0) {
+    co = rect_geom.xw;
+    uv = rect_icon.xw;
+  }
+  else if (gl_VertexID == 1) {
+    co = rect_geom.xy;
+    uv = rect_icon.xy;
+  }
+  else if (gl_VertexID == 2) {
+    co = rect_geom.zw;
+    uv = rect_icon.zw;
+  }
+  else {
+    co = rect_geom.zy;
+    uv = rect_icon.zy;
+  }
+#else
   if (gl_VertexID == 0) {
     co = rect_geom.xy;
     uv = rect_icon.xy;
@@ -31,6 +57,7 @@ void main()
     co = rect_geom.zy;
     uv = rect_icon.zy;
   }
+#endif
 
   gl_Position = ModelViewProjectionMatrix * vec4(co, 0.0f, 1.0f);
   texCoord_interp = uv;
diff --git a/source/blender/gpu/shaders/gpu_shader_2D_widget_base_vert.glsl b/source/blender/gpu/shaders/gpu_shader_2D_widget_base_vert.glsl
index 80b93baf20a..3a39cd8b847 100644
--- a/source/blender/gpu/shaders/gpu_shader_2D_widget_base_vert.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_2D_widget_base_vert.glsl
@@ -53,7 +53,7 @@ flat out float lineWidth;
 noperspective out float butCo;
 flat out float discardFac;
 
-#  ifdef OS_MAC
+#  if defined(OS_MAC) && defined(GPU_OPENGL)
 in float dummy;
 #  endif
 #endif
diff --git a/source/blender/gpu/shaders/gpu_shader_image_overlays_merge_frag.glsl b/source/blender/gpu/shaders/gpu_shader_image_overlays_merge_frag.glsl
index 2314dbbc5d5..aa182eb52be 100644
--- a/source/blender/gpu/shaders/gpu_shader_image_overlays_merge_frag.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_image_overlays_merge_frag.glsl
@@ -32,9 +32,9 @@ void linearrgb_to_srgb(vec4 col_from, out vec4 col_to)
 
 void main()
 {
-  fragColor = texture(image_texture, texCoord_interp.st);
-  vec4 overlay_col = texture(overlays_texture, texCoord_interp.st);
-
+  fragColor = texture(image_texture, texCoord_interp.xy);
+  vec4 overlay_col = texture(overlays_texture, texCoord_interp.xy);
+  
   if (overlay) {
     fragColor = clamp(fragColor, 0.0, 1.0);
     fragColor *= 1.0 - overlay_col.a;
diff --git a/source/blender/gpu/shaders/gpu_shader_keyframe_shape_vert.glsl b/source/blender/gpu/shaders/gpu_shader_keyframe_shape_vert.glsl
index 4ef3ff1a8d0..617c02ac079 100644
--- a/source/blender/gpu/shaders/gpu_shader_keyframe_shape_vert.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_keyframe_shape_vert.glsl
@@ -43,7 +43,7 @@ bool test(int bit)
 
 vec2 line_thresholds(float width)
 {
-  return vec2(max(0, width - line_falloff), width);
+  return vec2(max(0.0, width - line_falloff), width);
 }
 
 void main()
diff --git a/source/blender/gpu/shaders/gpu_shader_text_frag.glsl b/source/blender/gpu/shaders/gpu_shader_text_frag.glsl
index c339d3cbabb..f958a81b1eb 100644
--- a/source/blender/gpu/shaders/gpu_shader_text_frag.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_text_frag.glsl
@@ -52,7 +52,7 @@ bool is_inside_box(ivec2 v)
 
 float texture_1D_custom_bilinear_filter(vec2 uv)
 {
-  vec2 texel_2d = uv * glyph_dim + 0.5;
+  vec2 texel_2d = uv * vec2(glyph_dim) + vec2(0.5);
   ivec2 texel_2d_near = ivec2(texel_2d) - 1;
   int frag_offset = glyph_offset + texel_2d_near.y * glyph_dim.x + texel_2d_near.x;
 
@@ -100,7 +100,7 @@ void main()
     fragColor.a = texture_1D_custom_bilinear_filter(texCoord_interp);
   }
   else {
-    vec2 texel = 1.0 / glyph_dim;
+    vec2 texel = 1.0 / vec2(glyph_dim);
     fragColor.a = 0.0;
 
     if (interp_size == 1) {
diff --git a/source/blender/gpu/shaders/gpu_shader_text_vert.glsl b/source/blender/gpu/shaders/gpu_shader_text_vert.glsl
index 5b01fea5266..4221e426a3e 100644
--- a/source/blender/gpu/shaders/gpu_shader_text_vert.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_text_vert.glsl
@@ -29,7 +29,7 @@ void main()
   texCoord_interp = mix(-interp_offset, 1.0 + interp_offset, quad);
 
   vec2 final_pos = mix(
-      pos.xy + ivec2(-interp_size, interp_size), pos.zw + ivec2(interp_size, -interp_size), quad);
+      vec2(ivec2(pos.xy) + ivec2(-interp_size, interp_size)), vec2(ivec2(pos.zw) + ivec2(interp_size, -interp_size)), quad);
 
   gl_Position = ModelViewProjectionMatrix * vec4(final_pos, 0.0, 1.0);
 }
diff --git a/source/blender/gpu/shaders/material/gpu_shader_material_light_falloff.glsl b/source/blender/gpu/shaders/material/gpu_shader_material_light_falloff.glsl
index f3eae653f95..e1c7a00646f 100644
--- a/source/blender/gpu/shaders/material/gpu_shader_material_light_falloff.glsl
+++ b/source/blender/gpu/shaders/material/gpu_shader_material_light_falloff.glsl
@@ -1,7 +1,7 @@
 void node_light_falloff(
-    float strength, float tsmooth, out float quadratic, out float linear, out float constant)
+    float strength, float tsmooth, out float quadratic, out float linear, out float falloff_constant)
 {
   quadratic = strength;
   linear = strength;
-  constant = strength;
+  falloff_constant = strength;
 }
diff --git a/source/blender/gpu/shaders/opengl/glsl_shader_defines.glsl b/source/blender/gpu/shaders/opengl/glsl_shader_defines.glsl
new file mode 100644
index 00000000000..a5fce2e71c3
--- /dev/null
+++ b/source/blender/gpu/shaders/opengl/glsl_shader_defines.glsl
@@ -0,0 +1,17 @@
+/* Backend Functions. */
+#define select(A, B, mask) mix(A, B, mask)
+
+bool is_zero(vec2 A)
+{
+  return all(equal(A, vec2(0.0)));
+}
+
+bool is_zero(vec3 A)
+{
+  return all(equal(A, vec3(0.0)));
+}
+
+bool is_zero(vec4 A)
+{
+  return all(equal(A, vec4(0.0)));
+}