From d25c392cec57e8c561899bf75668da79c4e67aed Mon Sep 17 00:00:00 2001
From: Chuyan Zhang <chuyan@ucsb.edu>
Date: Wed, 9 Oct 2024 22:11:24 -0700
Subject: add shader compile infra

---
 src/render_pass.h | 23 +++++++++++++++++++
 src/shader.cpp    | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/shader.h      | 33 +++++++++++++++++++++++++++
 xmake.lua         |  3 ++-
 4 files changed, 125 insertions(+), 1 deletion(-)
 create mode 100644 src/render_pass.h
 create mode 100644 src/shader.cpp
 create mode 100644 src/shader.h

diff --git a/src/render_pass.h b/src/render_pass.h
new file mode 100644
index 0000000..b01bcae
--- /dev/null
+++ b/src/render_pass.h
@@ -0,0 +1,23 @@
+#pragma once
+
+enum struct RenderPassType {
+    RayTracing,
+    Compute,
+    Rasterization // Not intended to implement, want to make a pure ray tracer
+};
+
+struct RayTracingPass {
+    
+};
+
+struct ComputePass {
+
+};
+
+struct RenderPass {
+    RenderPassType type;
+    union {
+        RayTracingPass ray_tracing;
+        ComputePass compute;
+    } inner;
+};
diff --git a/src/shader.cpp b/src/shader.cpp
new file mode 100644
index 0000000..95a7904
--- /dev/null
+++ b/src/shader.cpp
@@ -0,0 +1,67 @@
+#include "shader.h"
+#include <spdlog/spdlog.h>
+#include <fstream>
+#include <sstream>
+#include <shaderc/shaderc.hpp>
+
+namespace iris {
+
+ShaderDesc::ShaderDesc(const std::string_view path) {
+    // Load the shader from file
+    std::ifstream file("example.txt");
+    if (!file.is_open()) {
+        spdlog::error("Failed to open shader file: {}", path);
+        abort();
+    }
+    std::ostringstream file_stream;
+    file_stream << file.rdbuf();
+    this->source = file_stream.str();
+    file.close();
+
+    // Determine the shader type
+    size_t last_dot = path.find_last_of('.');
+    if (last_dot == std::string::npos) {
+        spdlog::error("Invalid shader file type: {}", path);
+        abort();
+    }
+    size_t last_slash = path.find_last_of('/');
+    if (last_slash == std::string::npos) {
+        last_slash = 0;
+    }
+    this->name = path.substr(last_slash, last_dot - last_slash - 1);
+    this->type = shader_type_from_string(path.substr(last_dot + 1));
+
+    // Compile the shader to SPIR-V
+    shaderc::Compiler compiler;
+    shaderc::CompileOptions options;
+    options.SetTargetEnvironment(shaderc_target_env_vulkan, shaderc_env_version_vulkan_1_3);
+    
+    shaderc::SpvCompilationResult result = compiler.CompileGlslToSpv(
+        this->source, shaderc_glsl_compute_shader, path.data(), options);
+    if (result.GetCompilationStatus() != shaderc_compilation_status_success) {
+        spdlog::error("Failed to compile shader: {}", result.GetErrorMessage());
+        abort();
+    }
+    this->compiled_binary = std::vector<uint32_t>(result.cbegin(), result.cend());
+}
+
+ShaderDesc::Type ShaderDesc::shader_type_from_string(std::string_view type) {
+    if (type == "rgen") {
+        return ShaderDesc::Type::eRayGen;
+    } else if (type == "rmiss") {
+        return ShaderDesc::Type::eMiss;
+    } else if (type == "rchit") {
+        return ShaderDesc::Type::eClosestHit;
+    } else if (type == "rahit") {
+        return ShaderDesc::Type::eAnyHit;
+    } else if (type == "rint") {
+        return ShaderDesc::Type::eIntersection;
+    } else if (type == "comp") {
+        return ShaderDesc::Type::eCompute;
+    } else {
+        spdlog::error("Unknown shader type: {}", type);
+        abort();
+    }
+}
+
+} // namespace iris
\ No newline at end of file
diff --git a/src/shader.h b/src/shader.h
new file mode 100644
index 0000000..b1be8a8
--- /dev/null
+++ b/src/shader.h
@@ -0,0 +1,33 @@
+#pragma once
+#include <cstdint>
+#include <cstdlib>
+#include <string>
+#include <string_view>
+#include <vector>
+
+namespace iris {
+
+struct ShaderDesc {
+    // Name of the shader, filename if loaded from file
+    std::string name;
+    // Source code of the shader
+    std::string source;
+
+    // Shader type
+    enum struct Type {
+        eRayGen,
+        eMiss,
+        eClosestHit,
+        eAnyHit,
+        eIntersection,
+        eCompute,
+    } type;
+
+    // Compiled binary
+    std::vector<uint32_t> compiled_binary;
+
+    static Type shader_type_from_string(std::string_view type);
+    ShaderDesc(const std::string_view path);
+};
+
+} // namespace iris
\ No newline at end of file
diff --git a/xmake.lua b/xmake.lua
index eb1d750..41b1d0e 100644
--- a/xmake.lua
+++ b/xmake.lua
@@ -1,5 +1,6 @@
 add_rules("mode.debug", "mode.release")
 -- add_requires("vulkansdk", "glfw", "fmt", "vulkan-memory-allocator", "spdlog", "glm")
+add_requires("shaderc")
 
 -- Project settings
 set_project("iris_renderer")
@@ -70,7 +71,7 @@ target("iris_renderer")
     add_deps("argparse", "imgui", "tinygltf", "tinyobjloader", "stb", "glm")
 
     -- Add libraries
-    add_packages("vulkansdk", "glfw", "fmt", "vulkan-memory-allocator", "spdlog", "glm")
+    add_packages("vulkansdk", "glfw", "fmt", "vulkan-memory-allocator", "spdlog", "glm", "shaderc")
 
     -- OS-specific libraries (dl, pthread, X11, etc.)
     if is_plat("linux") then
-- 
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