constant buffers

1 files changed, 126 insertions, 1 deletions

diff --git a/sc/sc.cpp b/sc/sc.cpp
index f7acc1a..e806dd4 100644
--- a/sc/sc.cpp
+++ b/sc/sc.cpp
@@ -156,6 +156,27 @@ struct Desc {
 		int type;
 		std::string name;
 		std::string tname;
+
+		std::pair<int, int> size() const {
+			switch (type) {
+				case svariable_type_float:
+					return { 4, 4 };
+				case svariable_type_vec2:
+					return { 8, 8 };
+				case svariable_type_vec3:
+					return { 12, 16 };
+				case svariable_type_vec4:
+					return { 16, 16 };
+			}
+			assert(0);
+			return { 0, 0 };
+		}
+
+		int size(int coff) const {
+			auto [desired, align] = size();
+			int pad = align_size(coff, align) - coff;
+			return desired + pad;
+		}
 	};
 	struct Binding {
 		SBinding_Rate rate;
@@ -171,11 +192,24 @@ struct Desc {
 		int slot;
 		int stage;
 	};
+	struct Struct {
+		std::string name;
+		std::vector<Variable> vars;
+	};
+	struct CBuffer {
+		int size;
+		int stage;
+		int var_count;
+		std::string strct;
+		std::unordered_map<std::string, int> offsets;
+	};
 	int type;
 	std::vector<Binding> bindings;
 	std::vector<Variable> trgts;
 	std::vector<Variable> interp;
+	std::unordered_map<std::string, Struct> structs;
 	std::unordered_map<std::string, Texture> textures;
+	std::unordered_map<std::string, CBuffer> cbuffers;
 	std::vector<Descriptor> descriptors;
 	std::string entrypoints[shader_type_count];
 	void read_var(Variable& d, cfg_Object* desc) {
@@ -243,6 +277,66 @@ struct Desc {
 		t.stage |= 1 << stage_from_string(sstage);
 		t.dimension = find_int_default(desc, "dimension", 2);
 	}
+	cfg_Object* read_struct(cfg_Object* desc) {
+		const char* sname = find_string_default(desc, "name", 0);
+		if (!sname) {
+			print_err("%s must have a name.\n", desc->name);
+			pbreak(901);
+		}
+		std::string n = std::string(sname);
+		if (structs.contains(n)) {
+			print_err("Already a struct with the name %s.\n", sname);
+			pbreak(903);
+		}
+		desc = desc->next;
+		Struct& s = structs[n];
+		while (desc && !strcmp(desc->name, "variable")) {
+			Variable v;
+			read_var(v, desc);
+			s.vars.push_back(v);
+			desc = desc->next;
+		}
+		return desc;
+	}
+	
+	void read_cbuffer(cfg_Object* desc) {
+		const char* sname = find_string_default(desc, "name", 0);
+		if (!sname) {
+			print_err("%s must have a name.\n", desc->name);
+			pbreak(951);
+		}
+		const char* stype = find_string_default(desc, "type", 0);
+		if (!stype) {
+			print_err("%s must define a type.\n", desc->name);
+		}
+		std::string n = std::string(sname);
+		std::string t = std::string(stype);
+		if (n.size() > 23) {
+			print_err("CBuffer name too long (max 23 chars).\n");
+			pbreak(952);
+		}
+		if (!structs.contains(t)) {
+			print_err("No such struct %s\n", stype);
+			pbreak(953);
+		}
+		const char* sstage = find_string_default(desc, "stage", 0);
+		if (!sstage) {
+			print_err("%s must define a stage.\n", sname);
+			pbreak(954);
+		}
+		Struct& strct = structs[t];
+		CBuffer& buf = cbuffers[n];
+		int offset = 0;
+		buf.strct = t;
+		buf.stage |= 1 << stage_from_string(sstage);
+		buf.var_count = strct.vars.size();
+		for (const auto& v : strct.vars) {
+			buf.offsets[v.name] = offset;
+			offset += v.size(offset);
+		}
+		buf.size = offset;
+	}
+
 	void build(cfg_Object* desc) {
 		int i;
 		Binding* cur_binding = 0;
@@ -289,6 +383,11 @@ struct Desc {
 				interp.push_back(v);
 			} else if (!strcmp(desc->name, "texture")) {
 				read_texture(desc);
+			} else if (!strcmp(desc->name, "cbuffer")) {
+				read_cbuffer(desc);
+			} else if (!strcmp(desc->name, "struct")) {
+				desc = read_struct(desc);
+				continue;
 			}
 			desc = desc->next;
 		}
@@ -311,7 +410,7 @@ struct Desc {
 
 	void build_descriptors() {
 		int slot = 0;
-		descriptors.resize(textures.size());
+		descriptors.resize(textures.size() + cbuffers.size());
 		for (auto& i : textures) {
 			Descriptor* d = find_desc(i.first.c_str());
 			d->name = i.first;
@@ -319,6 +418,13 @@ struct Desc {
 			d->stage = i.second.stage;
 			slot++;
 		}
+		for (auto& i : cbuffers) {
+			Descriptor* d = find_desc(i.first.c_str());
+			d->name = i.first;
+			d->slot = slot;
+			d->stage = i.second.stage;
+			slot++;
+		}
 	}
 
 	void add_textures(std::stringstream& ss, Shader_Type stage) {
@@ -334,6 +440,23 @@ struct Desc {
 		}
 	}
 
+	void add_cbuffers(std::stringstream& ss, Shader_Type stage) {
+		for (const auto& it : cbuffers) {
+			const auto& cbuffer = it.second;
+			if (cbuffer.stage & (1 << stage)) {
+				const Struct& s = structs[cbuffer.strct];
+				Descriptor* d = find_desc(it.first.c_str());
+				assert(d != 0);
+				ss << "layout (std140, binding = " << d->slot << ") ";
+				ss << "uniform " << cbuffer.strct << "{\n";
+				for (const auto& v : s.vars) {
+					ss << v.tname << " " << v.name << ";\n";
+				}
+				ss << "} " << it.first << ";\n";
+			}
+		}
+	}
+
 	std::string build_vs() {
 		std::stringstream ss;
 		size_t i, li = bindings.size();
@@ -353,6 +476,7 @@ struct Desc {
 			ss << i.tname << " " << i.name << ";\n";
 		ss << "} interpolator;\n";
 		add_textures(ss, shader_type_vertex);
+		add_cbuffers(ss, shader_type_vertex);
 		return ss.str();
 	}
 
@@ -370,6 +494,7 @@ struct Desc {
 			ss << i.tname << " " << i.name << ";\n";
 		ss << "} interpolator;\n";
 		add_textures(ss, shader_type_fragment);
+		add_cbuffers(ss, shader_type_fragment);
 		return ss.str();
 	}
 };