From d6745226a171ba40e43ddbce63917d088112481c Mon Sep 17 00:00:00 2001
From: Patrick Wuttke <mewin@mewin.de>
Date: Fri, 13 Sep 2024 11:12:59 +0200
Subject: [PATCH] Implemented loading shaders from file.

---
 assets/shaders/glsl/green.frag    |  9 ++++++
 assets/shaders/glsl/triangle.vert | 12 ++++++++
 assets/shaders/hlsl/green.ps      | 12 ++++++++
 assets/shaders/hlsl/triangle.vs   | 19 ++++++++++++
 private/sdl_gpu_test/SModule      |  6 +++-
 private/sdl_gpu_test/main.cpp     | 50 +++++++++++++++++--------------
 6 files changed, 84 insertions(+), 24 deletions(-)
 create mode 100644 assets/shaders/glsl/green.frag
 create mode 100644 assets/shaders/glsl/triangle.vert
 create mode 100644 assets/shaders/hlsl/green.ps
 create mode 100644 assets/shaders/hlsl/triangle.vs

diff --git a/assets/shaders/glsl/green.frag b/assets/shaders/glsl/green.frag
new file mode 100644
index 0000000..44583fc
--- /dev/null
+++ b/assets/shaders/glsl/green.frag
@@ -0,0 +1,9 @@
+#version 460
+
+layout(location = 0)
+out vec4 o_color;
+
+void main()
+{
+    o_color = vec4(0.0, 1.0, 0.0, 1.0);
+}
diff --git a/assets/shaders/glsl/triangle.vert b/assets/shaders/glsl/triangle.vert
new file mode 100644
index 0000000..126fd34
--- /dev/null
+++ b/assets/shaders/glsl/triangle.vert
@@ -0,0 +1,12 @@
+#version 460
+
+const vec2 vertices[3] = vec2[3](
+    vec2(-0.5, 0.5),
+    vec2( 0.5, 0.5),
+    vec2( 0.0, -0.5)
+);
+
+void main()
+{
+    gl_Position = vec4(vertices[gl_VertexIndex], 0.0, 1.0);
+}
diff --git a/assets/shaders/hlsl/green.ps b/assets/shaders/hlsl/green.ps
new file mode 100644
index 0000000..c8e07a7
--- /dev/null
+++ b/assets/shaders/hlsl/green.ps
@@ -0,0 +1,12 @@
+
+struct PS_OUTPUT
+{
+    float4 color : COLOR0;
+};
+
+PS_OUTPUT main() : SV_TARGET
+{
+    PS_OUTPUT output;
+    output.color = float4(0.0, 1.0, 0.0, 1.0);
+    return output;
+}
diff --git a/assets/shaders/hlsl/triangle.vs b/assets/shaders/hlsl/triangle.vs
new file mode 100644
index 0000000..9037b8e
--- /dev/null
+++ b/assets/shaders/hlsl/triangle.vs
@@ -0,0 +1,19 @@
+
+struct VS_OUTPUT
+{
+    float4 vPosition : POSITION;
+};
+
+static const float2 vertices[3] =
+{
+    float2(-0.5, 0.5),
+    float2( 0.5, 0.5),
+    float2( 0.0, -0.5)
+};
+
+VS_OUTPUT main(uint vertexID : SV_VertexID)
+{
+    VS_OUTPUT output;
+    output.vPosition = float4(vertices[vertexID], 0.0, 1.0);
+    return output;
+}
diff --git a/private/sdl_gpu_test/SModule b/private/sdl_gpu_test/SModule
index df916ff..e7b5a2c 100644
--- a/private/sdl_gpu_test/SModule
+++ b/private/sdl_gpu_test/SModule
@@ -18,7 +18,11 @@ prog_app = env.UnityProgram(
             }
         },
         'spdlog': {},
-        'glslang': {}
+        'glslang': {
+            'options': {
+                'enable_hlsl': True
+            }
+        }
     }
 )
 env.Default(prog_app)
diff --git a/private/sdl_gpu_test/main.cpp b/private/sdl_gpu_test/main.cpp
index 185bfae..b979c89 100644
--- a/private/sdl_gpu_test/main.cpp
+++ b/private/sdl_gpu_test/main.cpp
@@ -1,6 +1,9 @@
 
 #include <mijin/util/scope_guard.hpp>
 #include <mijin/util/variant.hpp>
+#include <mijin/virtual_filesystem/filesystem.hpp>
+#include <mijin/virtual_filesystem/relative.hpp>
+#include <mijin/virtual_filesystem/stacked.hpp>
 #include <spdlog/spdlog.h>
 #include <mijin/util/winundef.hpp>
 
@@ -11,38 +14,36 @@
 
 namespace
 {
-const char* const VERTEX_SOURCE = R"(
-#version 460
+mijin::StackedFileSystemAdapter gFileSystem;
 
-const vec2 vertices[3] = vec2[3](
-    vec2(-0.5, 0.5),
-    vec2( 0.5, 0.5),
-    vec2( 0.0, -0.5)
-);
-
-void main()
+void initFileSystem(const fs::path& executablePath) noexcept
 {
-    gl_Position = vec4(vertices[gl_VertexIndex], 0.0, 1.0);
+    gFileSystem.emplaceAdapter<mijin::RelativeFileSystemAdapter<mijin::OSFileSystemAdapter>>(executablePath.parent_path() / "assets");
 }
-)";
 
-const char* const FRAGMENT_SOURCE = R"(
-#version 460
-
-layout(location = 0)
-out vec4 o_color;
-
-void main()
+[[nodiscard]]
+std::string getFileContents(const fs::path& path)
 {
-    o_color = vec4(0.0, 1.0, 0.0, 1.0);
+    std::unique_ptr<mijin::Stream> stream;
+    mijin::throwOnError(gFileSystem.open(path, mijin::FileOpenMode::READ, stream),
+              "Error opening file for reading.");
+    std::string content;
+    mijin::throwOnError(stream->readAsString(content), "Error reading file contents.");
+    return content;
 }
-)";
 }
 
-int main(int, char**)
+int main(int argc, char* argv[])
 {
     using namespace sdl_gpu_test;
 
+    if (argc < 1)
+    {
+        return 1;
+    }
+
+    initFileSystem(fs::absolute(fs::path(argv[0])).parent_path());
+
     // init SDL
     if (SDL_Init(0) != SDL_TRUE)
     {
@@ -61,6 +62,7 @@ int main(int, char**)
 
     sdlpp::Window window;
     window.create({
+        .title = "SDL_gpu Test",
         .flags = {.vulkan = true}
     });
 
@@ -73,7 +75,8 @@ int main(int, char**)
     gpuDevice.claimWindow(window);
 
     // create vertex shader
-    std::vector<std::uint32_t> vertexSpv = compileGLSL(VERTEX_SOURCE, {.stage =  ShaderStage::VERTEX});
+    const std::string vertexSource = getFileContents("shaders/glsl/triangle.vert");
+    std::vector<std::uint32_t> vertexSpv = compileGLSL(vertexSource, {.stage =  ShaderStage::VERTEX});
     sdlpp::GPUShader vertexShader;
     vertexShader.create(gpuDevice, {
         .code = {reinterpret_cast<const Uint8*>(vertexSpv.data()), vertexSpv.size() * sizeof(std::uint32_t)},
@@ -82,7 +85,8 @@ int main(int, char**)
     });
 
     // create fragment shader
-    std::vector<std::uint32_t> fragmentSpv = compileGLSL(FRAGMENT_SOURCE, {.stage =  ShaderStage::FRAGMENT});
+    const std::string fragmentSource = getFileContents("shaders/glsl/green.frag");
+    std::vector<std::uint32_t> fragmentSpv = compileGLSL(fragmentSource, {.stage =  ShaderStage::FRAGMENT});
     sdlpp::GPUShader fragmentShader;
     fragmentShader.create(gpuDevice, {
         .code = {reinterpret_cast<const Uint8*>(fragmentSpv.data()), fragmentSpv.size() * sizeof(std::uint32_t)},