pyGPU: Port 'StageInterfaceInfo' and 'ShaderCreateInfo' types

In order to allow GLSL Cross Compilation across platforms, expose in
Python the `GPUShaderCreateInfo` strategy as detailed in
https://wiki.blender.org/wiki/EEVEE_%26_Viewport/GPU_Module/GLSL_Cross_Compilation

The new features can be listed as follows:
```
>>> gpu.types.GPUShaderCreateInfo.
                                  define(
                                  fragment_out(
                                  fragment_source(
                                  push_constant(
                                  sampler(
                                  typedef_source(
                                  uniform_buf(
                                  vertex_in(
                                  vertex_out(
                                  vertex_source(

>>> gpu.types.GPUStageInterfaceInfo.
                                    flat(
                                    name
                                    no_perspective(
                                    smooth(

>>> gpu.shader.create_from_info(
```

Reviewed By: fclem, campbellbarton

Differential Revision: https://developer.blender.org/D14497

4 files changed, 48 insertions, 22 deletions

diff --git a/source/blender/gpu/GPU_shader.h b/source/blender/gpu/GPU_shader.h
index c0c25022836..eed7685bf01 100644
--- a/source/blender/gpu/GPU_shader.h
+++ b/source/blender/gpu/GPU_shader.h
@@ -56,6 +56,7 @@ GPUShader *GPU_shader_create_from_info(const GPUShaderCreateInfo *_info);
 GPUShader *GPU_shader_create_from_info_name(const char *info_name);
 
 const GPUShaderCreateInfo *GPU_shader_create_info_get(const char *info_name);
+bool GPU_shader_create_info_check_error(const GPUShaderCreateInfo *_info, char r_error[128]);
 
 struct GPU_ShaderCreateFromArray_Params {
   const char **vert, **geom, **frag, **defs;
diff --git a/source/blender/gpu/intern/gpu_shader.cc b/source/blender/gpu/intern/gpu_shader.cc
index b434cfbbb0e..227525bd5d3 100644
--- a/source/blender/gpu/intern/gpu_shader.cc
+++ b/source/blender/gpu/intern/gpu_shader.cc
@@ -249,6 +249,19 @@ const GPUShaderCreateInfo *GPU_shader_create_info_get(const char *info_name)
   return gpu_shader_create_info_get(info_name);
 }
 
+bool GPU_shader_create_info_check_error(const GPUShaderCreateInfo *_info, char r_error[128])
+{
+  using namespace blender::gpu::shader;
+  const ShaderCreateInfo &info = *reinterpret_cast<const ShaderCreateInfo *>(_info);
+  std::string error = info.check_error();
+  if (error.length() == 0) {
+    return true;
+  }
+
+  BLI_strncpy(r_error, error.c_str(), 128);
+  return false;
+}
+
 GPUShader *GPU_shader_create_from_info_name(const char *info_name)
 {
   using namespace blender::gpu::shader;
@@ -270,28 +283,10 @@ GPUShader *GPU_shader_create_from_info(const GPUShaderCreateInfo *_info)
 
   GPU_debug_group_begin(GPU_DEBUG_SHADER_COMPILATION_GROUP);
 
-  /* At least a vertex shader and a fragment shader are required, or only a compute shader. */
-  if (info.compute_source_.is_empty()) {
-    if (info.vertex_source_.is_empty()) {
-      printf("Missing vertex shader in %s.\n", info.name_.c_str());
-    }
-    if (info.fragment_source_.is_empty()) {
-      printf("Missing fragment shader in %s.\n", info.name_.c_str());
-    }
-    BLI_assert(!info.vertex_source_.is_empty() && !info.fragment_source_.is_empty());
-  }
-  else {
-    if (!info.vertex_source_.is_empty()) {
-      printf("Compute shader has vertex_source_ shader attached in %s.\n", info.name_.c_str());
-    }
-    if (!info.geometry_source_.is_empty()) {
-      printf("Compute shader has geometry_source_ shader attached in %s.\n", info.name_.c_str());
-    }
-    if (!info.fragment_source_.is_empty()) {
-      printf("Compute shader has fragment_source_ shader attached in %s.\n", info.name_.c_str());
-    }
-    BLI_assert(info.vertex_source_.is_empty() && info.geometry_source_.is_empty() &&
-               info.fragment_source_.is_empty());
+  std::string error = info.check_error();
+  if (error.length()) {
+    printf(error.c_str());
+    BLI_assert(true);
   }
 
   Shader *shader = GPUBackend::get()->shader_alloc(info.name_.c_str());
diff --git a/source/blender/gpu/intern/gpu_shader_create_info.cc b/source/blender/gpu/intern/gpu_shader_create_info.cc
index 0dd82d4ea44..6e82201b424 100644
--- a/source/blender/gpu/intern/gpu_shader_create_info.cc
+++ b/source/blender/gpu/intern/gpu_shader_create_info.cc
@@ -136,6 +136,34 @@ void ShaderCreateInfo::finalize()
   }
 }
 
+std::string ShaderCreateInfo::check_error() const
+{
+  std::string error;
+
+  /* At least a vertex shader and a fragment shader are required, or only a compute shader. */
+  if (this->compute_source_.is_empty()) {
+    if (this->vertex_source_.is_empty()) {
+      error += "Missing vertex shader in " + this->name_ + ".\n";
+    }
+    if (this->fragment_source_.is_empty()) {
+      error += "Missing fragment shader in " + this->name_ + ".\n";
+    }
+  }
+  else {
+    if (!this->vertex_source_.is_empty()) {
+      error += "Compute shader has vertex_source_ shader attached in" + this->name_ + ".\n";
+    }
+    if (!this->geometry_source_.is_empty()) {
+      error += "Compute shader has geometry_source_ shader attached in" + this->name_ + ".\n";
+    }
+    if (!this->fragment_source_.is_empty()) {
+      error += "Compute shader has fragment_source_ shader attached in" + this->name_ + ".\n";
+    }
+  }
+
+  return error;
+}
+
 void ShaderCreateInfo::validate(const ShaderCreateInfo &other_info)
 {
   if (!auto_resource_location_) {
diff --git a/source/blender/gpu/intern/gpu_shader_create_info.hh b/source/blender/gpu/intern/gpu_shader_create_info.hh
index 51008993353..dfd73219d1b 100644
--- a/source/blender/gpu/intern/gpu_shader_create_info.hh
+++ b/source/blender/gpu/intern/gpu_shader_create_info.hh
@@ -787,6 +787,8 @@ struct ShaderCreateInfo {
   /* WARNING: Recursive. */
   void finalize();
 
+  std::string check_error() const;
+
   /** Error detection that some backend compilers do not complain about. */
   void validate(const ShaderCreateInfo &other_info);