GPUShader: Improve builtins support in GPUShaderCreateInfo

- Scan all static shaders for builtins on startup.
- Add possibility to manually add builtins.
- `ShaderCreateInfo.builtins_` contain builtins from all stages.

source/blender/gpu/intern/gpu_shader.cc

@@ -314,9 +314,8 @@ GPUShader *GPU_shader_create_from_info(const GPUShaderCreateInfo *_info)
   }
 
   if (!info.vertex_source_.is_empty()) {
-    uint32_t builtins = 0;
+    char *code = gpu_shader_dependency_get_resolved_source(info.vertex_source_.c_str());
     std::string interface = shader->vertex_interface_declare(info);
-    char *code = gpu_shader_dependency_get_resolved_source(info.vertex_source_.c_str(), &builtins);
 
     Vector<const char *> sources;
     standard_defines(sources);
@@ -341,10 +340,8 @@ GPUShader *GPU_shader_create_from_info(const GPUShaderCreateInfo *_info)
   }
 
   if (!info.fragment_source_.is_empty()) {
-    uint32_t builtins = 0;
+    char *code = gpu_shader_dependency_get_resolved_source(info.fragment_source_.c_str());
     std::string interface = shader->fragment_interface_declare(info);
-    char *code = gpu_shader_dependency_get_resolved_source(info.fragment_source_.c_str(),
-                                                           &builtins);
 
     Vector<const char *> sources;
     standard_defines(sources);
@@ -369,11 +366,9 @@ GPUShader *GPU_shader_create_from_info(const GPUShaderCreateInfo *_info)
   }
 
   if (!info.geometry_source_.is_empty()) {
-    uint32_t builtins = 0;
-    std::string interface = shader->geometry_interface_declare(info);
+    char *code = gpu_shader_dependency_get_resolved_source(info.geometry_source_.c_str());
     std::string layout = shader->geometry_layout_declare(info);
-    char *code = gpu_shader_dependency_get_resolved_source(info.geometry_source_.c_str(),
-                                                           &builtins);
+    std::string interface = shader->geometry_interface_declare(info);
 
     Vector<const char *> sources;
     standard_defines(sources);
@@ -396,9 +391,7 @@ GPUShader *GPU_shader_create_from_info(const GPUShaderCreateInfo *_info)
   }
 
   if (!info.compute_source_.is_empty()) {
-    uint32_t builtins = 0;
-    char *code = gpu_shader_dependency_get_resolved_source(info.compute_source_.c_str(),
-                                                           &builtins);
+    char *code = gpu_shader_dependency_get_resolved_source(info.compute_source_.c_str());
     std::string layout = shader->compute_layout_declare(info);
 
     Vector<const char *> sources;

source/blender/gpu/intern/gpu_shader_create_info.cc

@@ -34,6 +34,7 @@
 
 #include "gpu_shader_create_info.hh"
 #include "gpu_shader_create_info_private.hh"
+#include "gpu_shader_dependency_private.h"
 #include "gpu_shader_private.hh"
 
 #undef GPU_SHADER_INTERFACE_INFO
@@ -209,6 +210,19 @@ void gpu_shader_create_info_init()
     draw_modelmat = draw_modelmat_legacy;
   }
 
+  for (ShaderCreateInfo *info : g_create_infos->values()) {
+    if (info->do_static_compilation_) {
+      info->builtins_ |= static_cast<BuiltinBits>(
+          gpu_shader_dependency_get_builtins(info->vertex_source_.c_str()));
+      info->builtins_ |= static_cast<BuiltinBits>(
+          gpu_shader_dependency_get_builtins(info->fragment_source_.c_str()));
+      info->builtins_ |= static_cast<BuiltinBits>(
+          gpu_shader_dependency_get_builtins(info->geometry_source_.c_str()));
+      info->builtins_ |= static_cast<BuiltinBits>(
+          gpu_shader_dependency_get_builtins(info->compute_source_.c_str()));
+    }
+  }
+
   /* TEST */
   // gpu_shader_create_info_compile_all();
 }

source/blender/gpu/intern/gpu_shader_create_info.hh

@@ -63,6 +63,7 @@ enum class Type {
 };
 
 enum class BuiltinBits {
+  NONE = 0,
   /**
    * Allow getting barycentric coordinates inside the fragment shader.
    * \note Emulated on OpenGL.
@@ -72,6 +73,10 @@ enum class BuiltinBits {
   FRONT_FACING = (1 << 4),
   GLOBAL_INVOCATION_ID = (1 << 5),
   INSTANCE_ID = (1 << 6),
+  /**
+   * Allow setting the target layer when the output is a layered framebuffer.
+   * \note Emulated through geometry shader on older hardware.
+   */
   LAYER = (1 << 7),
   LOCAL_INVOCATION_ID = (1 << 8),
   LOCAL_INVOCATION_INDEX = (1 << 9),
@@ -226,6 +231,8 @@ struct ShaderCreateInfo {
    * Only for names used by gpu::ShaderInterface.
    */
   size_t interface_names_size_ = 0;
+  /** Manually set builtins. */
+  BuiltinBits builtins_ = BuiltinBits::NONE;
 
   struct VertIn {
     int index;
@@ -538,6 +545,12 @@ struct ShaderCreateInfo {
     return *(Self *)this;
   }
 
+  Self &builtins(BuiltinBits builtin)
+  {
+    builtins_ |= builtin;
+    return *(Self *)this;
+  }
+
   /** \} */
 
   /* -------------------------------------------------------------------- */

source/blender/gpu/intern/gpu_shader_dependency.cc

@@ -59,7 +59,6 @@ struct GPUSource {
     /* Scan for builtins. */
     /* FIXME: This can trigger false positive caused by disabled #if blocks. */
     /* TODO(fclem): Could be made faster by scanning once. */
-    /* TODO(fclem): BARYCENTRIC_COORD. */
     if (source.find("gl_FragCoord", 0)) {
       builtins |= shader::BuiltinBits::FRAG_COORD;
     }
@@ -72,9 +71,6 @@ struct GPUSource {
     if (source.find("gl_InstanceID", 0)) {
       builtins |= shader::BuiltinBits::INSTANCE_ID;
     }
-    if (source.find("gl_Layer", 0)) {
-      builtins |= shader::BuiltinBits::LAYER;
-    }
     if (source.find("gl_LocalInvocationID", 0)) {
       builtins |= shader::BuiltinBits::LOCAL_INVOCATION_ID;
     }
@@ -336,13 +332,23 @@ struct GPUSource {
   }
 
   /* Returns the final string with all includes done. */
-  void build(std::string &str, shader::BuiltinBits &out_builtins)
+  std::string build() const
   {
+    std::string str;
     for (auto *dep : dependencies) {
-      out_builtins |= builtins;
       str += dep->source;
     }
     str += source;
+    return str;
+  }
+
+  shader::BuiltinBits builtins_get() const
+  {
+    shader::BuiltinBits out_builtins = shader::BuiltinBits::NONE;
+    for (auto *dep : dependencies) {
+      out_builtins |= dep->builtins;
+    }
+    return out_builtins;
   }
 };
 
@@ -377,14 +383,19 @@ void gpu_shader_dependency_exit()
   delete g_sources;
 }
 
-char *gpu_shader_dependency_get_resolved_source(const char *shader_source_name, uint32_t *builtins)
+uint32_t gpu_shader_dependency_get_builtins(const char *shader_source_name)
+{
+  if (shader_source_name[0] == '\0') {
+    return 0;
+  }
+  GPUSource *source = g_sources->lookup(shader_source_name);
+  return static_cast<uint32_t>(source->builtins_get());
+}
+
+char *gpu_shader_dependency_get_resolved_source(const char *shader_source_name)
 {
   GPUSource *source = g_sources->lookup(shader_source_name);
-  std::string str;
-  shader::BuiltinBits out_builtins;
-  source->build(str, out_builtins);
-  *builtins |= (uint32_t)out_builtins;
-  return strdup(str.c_str());
+  return strdup(source->build().c_str());
 }
 
 char *gpu_shader_dependency_get_source(const char *shader_source_name)

source/blender/gpu/intern/gpu_shader_dependency_private.h

@@ -35,10 +35,11 @@ void gpu_shader_dependency_init(void);
 void gpu_shader_dependency_exit(void);
 
 /* User must free the resulting string using free. */
-char *gpu_shader_dependency_get_resolved_source(const char *shader_source_name,
-                                                uint32_t *builtins);
+char *gpu_shader_dependency_get_resolved_source(const char *shader_source_name);
 char *gpu_shader_dependency_get_source(const char *shader_source_name);
 
+uint32_t gpu_shader_dependency_get_builtins(const char *shader_source_name);
+
 #ifdef __cplusplus
 }
 #endif