Updated to work with newer version of shaderc

CMakeLists.txt

@@ -34,6 +34,7 @@ include(HandleLLVMOptions)
 
 if(EXISTS "${CMAKE_CURRENT_LIST_DIR}/vendor/shaderc/CMakeLists.txt")
     set(SHADERC_SKIP_TESTS ON)
+    set(SHADERC_ENABLE_WERROR_COMPILE OFF)
     add_subdirectory(vendor/shaderc)
 
 else()

README.md

@@ -6,3 +6,15 @@ echo deb https://apt.llvm.org/bullseye llvm-toolchain-bullseye-14 main >/etc/apt
 apt install llvm-14-tools clang build-essential cmake git \ 
     llvm-14-dev libboost-log-dev spirv-headers spirv-tools
 ```
+
+Clone the source, then in the source dir:
+
+```shell
+git submodule update --init vendor/shaderc
+vendor/shaderc/utils/git-sync-deps
+mkdir build
+cd build
+cmake -DCMAKE_BUILD_PROFILE=Release ..
+# Note: just running `make` will fail with a link error in render_stub.c; ignore this. 
+make bluebell
+```

src/pre-compiler.cpp

@@ -16,7 +16,7 @@ std::shared_ptr<std::vector<uint32_t>> pre_compile_shader(const std::string &src
 //    options.SetOptimizationLevel(shaderc_optimization_level_performance);
     options.SetTargetSpirv(shaderc_spirv_version_1_0);
     options.SetTargetEnvironment(
-            shaderc_target_env_opengl_compat,
+            shaderc_target_env_opengl,
             shaderc_env_version::shaderc_env_version_opengl_4_5);
 
 

src/render_frame/render_stub.c

@@ -18,6 +18,10 @@
 #ifndef FRAME_COUNT
 #define FRAME_COUNT 100
 #endif
+#ifndef MSAA
+// Multisample anti-aliasing count (will actually sample MSAA^2 points)
+#define MSAA 1
+#endif
 
 // render API:
 struct Uniforms {
@@ -56,7 +60,6 @@ const char* PPM_HDR = "P6\n" STRINGIFY(FRAME_DIM) " " STRINGIFY(FRAME_DIM) "\n25
 unsigned char frame_buf[FRAME_DIM][FRAME_DIM][3];
 
 unsigned char linear_to_srgb(float lin) {
-    float srgb;
     if (lin < 0) {
         return 0;
     } else if (lin > 1) {
@@ -64,7 +67,7 @@ unsigned char linear_to_srgb(float lin) {
     } else if (lin < 0.0031308) {
         return (unsigned char)(lin * 12.92);
     } else {
-        float srgb = (powf(lin, 1.0f/2.4f) * 1.055f - 0.055f) * 256;
+        float srgb = (powf(lin, 1.0f/2.4f) * 1.055f - 0.055f) * 256.f;
         if (srgb > 255.f) {
             return 255;
         } else {
@@ -72,6 +75,13 @@ unsigned char linear_to_srgb(float lin) {
         }
     }
 }
+float srgb_to_linear(float srgb) {
+    if (srgb < 0.04045f) {
+        return srgb/12.92f;
+    } else {
+        return powf((srgb+0.055f)/1.055f, 2.4f);
+    }
+}
 
 int main(int argc, char** argv) {
     unsigned header_len = strlen(PPM_HDR);
@@ -87,14 +97,23 @@ int main(int argc, char** argv) {
         for (int y = 0; y < FRAME_DIM; y++) {
             for (int x = 0; x < FRAME_DIM; x++) {
                 float pixel[3];
+                float pixel_accum[3] = {0.f,0.f,0.f};
                 unsigned char *pxl_dst = frame_buf[y][x];
-//                printf("-- pixel %f,%f\n", (x+0.5f), (y+0.5f));
+                for (int ss_x = 0; ss_x < MSAA; ss_x++) {
-                render_pixel(ctx, (x + 0.5f), (y + 0.5f), pixel);
+                    for (int ss_y = 0; ss_y < MSAA; ss_y++) {
+                        float rx = (0.5f + (float)ss_x) / (float)MSAA + (float)x;
+                        float ry = (0.5f + (float)ss_y) / (float)MSAA + (float)y;
+                        render_pixel(ctx, rx, ry, pixel);
+                        for (int i = 0; i < 3; i++) {
+                            pixel_accum[i] += srgb_to_linear(pixel[i]);
+                        }
+                    }
+                }
                 for (int i = 0; i < 3; i++) {
-                    pixel[i] *= 256;
+//                    pixel_accum[i] *= 256;
-                    if (pixel[i] < 0) { pixel[i] = 0; }
+//                    if (pixel_accum[i] < 0) { pixel_accum[i] = 0; }
-                    if (pixel[i] > 255) { pixel[i] = 255; }
+//                    if (pixel_accum[i] > 255) { pixel_accum[i] = 255; }
-                    pxl_dst[i] = (unsigned char) pixel[i];
+                    pxl_dst[i] = linear_to_srgb(pixel_accum[i]/(float)(MSAA*MSAA));
                 }
             }
         }