OpenGL backend on windows

build.bat

@@ -33,6 +33,7 @@ if "%debug%"=="1"   set release=0 && echo [debug mode]
 if "%release%"=="1" set debug=0 && echo [release mode]
 if "%msvc%"=="1"    set clang=0 && echo [msvc compile]
 if "%clang%"=="1"   set msvc=0 && echo [clang compile]
+if "%opengl%"=="1"  echo [opengl backend]
 if "%~1"==""        echo [default mode, assuming `raddbg` build] && set raddbg=1
 
 :: --- Unpack Command Line Build Arguments ------------------------------------
@@ -85,6 +86,9 @@ popd
 :: --- Get Current Git Commit Id ----------------------------------------------
 for /f %%i in ('call git describe --always --dirty') do set compile=%compile% -DBUILD_GIT_HASH=\"%%i\"
 
+:: --- Set rendering backend -----------------------------------------------
+if "%opengl%"=="1" set compile=%compile% -DR_BACKEND=2 -DBUILD_RENDERING_BACKEND=\"OpenGL\"
+
 :: --- Build & Run Metaprogram ------------------------------------------------
 if "%no_meta%"=="1" echo [skipping metagen]
 if not "%no_meta%"=="1" (

src/base/base_context_cracking.h

@@ -173,6 +173,11 @@
 #else
 # define BUILD_GIT_HASH_STRING_LITERAL_APPEND ""
 #endif
+#if defined(BUILD_RENDERING_BACKEND)
+# define BUILD_RENDERING_BACKEND_STRING_LITERAL_APPEND " [" BUILD_RENDERING_BACKEND "]"
+#else
+# define BUILD_RENDERING_BACKEND_STRING_LITERAL_APPEND ""
+#endif
 
 #if !defined(BUILD_TITLE)
 # define BUILD_TITLE "Untitled"
@@ -186,7 +191,7 @@
 # define BUILD_ISSUES_LINK_STRING_LITERAL "https://github.com/EpicGames/raddebugger/issues"
 #endif
 
-#define BUILD_TITLE_STRING_LITERAL BUILD_TITLE " (" BUILD_VERSION_STRING_LITERAL " " BUILD_RELEASE_PHASE_STRING_LITERAL ") - " __DATE__ "" BUILD_GIT_HASH_STRING_LITERAL_APPEND BUILD_MODE_STRING_LITERAL_APPEND
+#define BUILD_TITLE_STRING_LITERAL BUILD_TITLE " (" BUILD_VERSION_STRING_LITERAL " " BUILD_RELEASE_PHASE_STRING_LITERAL ") - " __DATE__ "" BUILD_GIT_HASH_STRING_LITERAL_APPEND BUILD_MODE_STRING_LITERAL_APPEND "" BUILD_RENDERING_BACKEND_STRING_LITERAL_APPEND
 
 ////////////////////////////////
 //~ rjf: Zero All Undefined Options

src/render/d3d11/render_d3d11.cpp

@@ -1230,64 +1230,29 @@ r_window_submit(OS_Handle window, R_Handle window_equip, R_PassList *passes)
           // rjf: set up uniforms
           R_D3D11_Uniforms_Blur uniforms = { 0 };
           {
-            F32 weights[ArrayCount(uniforms.kernel)*2] = {0};
-
-            F32 blur_size = Min(params->blur_size, ArrayCount(weights));
-            U64 blur_count = (U64)round_f32(blur_size);
-
-            F32 stdev = (blur_size-1.f)/2.f;
-            F32 one_over_root_2pi_stdev2 = 1/sqrt_f32(2*pi32*stdev*stdev);
-            F32 euler32 = 2.718281828459045f;
-
-            weights[0] = 1.f;
-            if(stdev > 0.f)
-            {
-              for(U64 idx = 0; idx < blur_count; idx += 1)
-              {
-                F32 kernel_x = (F32)idx;
-                weights[idx] = one_over_root_2pi_stdev2*pow_f32(euler32, -kernel_x*kernel_x/(2.f*stdev*stdev)); 
-              }
-            }
-            if(weights[0] > 1.f)
+            R_Blur_Kernel kernel = {0};
+            r_fill_blur_kernel(params->blur_size, &kernel);
+
+            // each kernel element is float2(weight, offset)
+            // weights & offsets are adjusted for bilinear sampling
+            // zw elements are not used, a bit of waste but it allows for simpler shader code
+            for(U64 i = 0; i < ArrayCount(uniforms.kernel); i++)
             {
-              MemoryZeroArray(weights);
-              weights[0] = 1.f;
+              uniforms.kernel[i] = v4f32(kernel.weights[i].x, kernel.weights[i].y, 0, 0);
             }
-            else
-            {
-              // prepare weights & offsets for bilinear lookup
-              // blur filter wants to calculate w0*pixel[pos] + w1*pixel[pos+1] + ...
-              // with bilinear filter we can do this calulation by doing only w*sample(pos+t) = w*((1-t)*pixel[pos] + t*pixel[pos+1])
-              // we can see w0=w*(1-t) and w1=w*t
-              // thus w=w0+w1 and t=w1/w
-              for (U64 idx = 1; idx < blur_count; idx += 2)
-              {
-                F32 w0 = weights[idx + 0];
-                F32 w1 = weights[idx + 1];
-                F32 w = w0 + w1;
-                F32 t = w1 / w;
-
-                // each kernel element is float2(weight, offset)
-                // weights & offsets are adjusted for bilinear sampling
-                // zw elements are not used, a bit of waste but it allows for simpler shader code
-                uniforms.kernel[(idx+1)/2] = v4f32(w, (F32)idx + t, 0, 0);
-              }
-            }
-            uniforms.kernel[0].x = weights[0];
-
             // technically we need just direction be different
             // but there are 256 bytes of usable space anyway for each constant buffer chunk
 
             uniforms.passes[Axis2_X].viewport_size = v2f32(resolution.x, resolution.y);
             uniforms.passes[Axis2_X].rect          = params->rect;
             uniforms.passes[Axis2_X].direction     = v2f32(1.f / resolution.x, 0);
-            uniforms.passes[Axis2_X].blur_count    = 1 + blur_count / 2; // 2x smaller because of bilinear sampling
+            uniforms.passes[Axis2_X].blur_count    = 1 + kernel.blur_count / 2; // 2x smaller because of bilinear sampling
             MemoryCopyArray(uniforms.passes[Axis2_X].corner_radii.v, params->corner_radii);
 
             uniforms.passes[Axis2_Y].viewport_size = v2f32(resolution.x, resolution.y);
             uniforms.passes[Axis2_Y].rect          = params->rect;
             uniforms.passes[Axis2_Y].direction     = v2f32(0, 1.f / resolution.y);
-            uniforms.passes[Axis2_Y].blur_count    = 1 + blur_count / 2; // 2x smaller because of bilinear sampling
+            uniforms.passes[Axis2_Y].blur_count    = 1 + kernel.blur_count / 2; // 2x smaller because of bilinear sampling
             MemoryCopyArray(uniforms.passes[Axis2_Y].corner_radii.v, params->corner_radii);
 
             D3D11_MAPPED_SUBRESOURCE sub_rsrc = {0};

src/render/d3d11/render_d3d11.h

@@ -46,7 +46,7 @@ StaticAssert(sizeof(R_D3D11_Uniforms_BlurPass) % 256 == 0, NotAligned); // const
 struct R_D3D11_Uniforms_Blur
 {
   R_D3D11_Uniforms_BlurPass passes[Axis2_COUNT];
-  Vec4F32 kernel[32];
+  Vec4F32 kernel[ArrayCount(R_Blur_Kernel::weights)];
 };
 
 struct R_D3D11_Uniforms_Mesh

src/render/opengl/generated/render_opengl.meta.c

@@ -0,0 +1,8 @@
+// Copyright (c) 2024 Epic Games Tools
+// Licensed under the MIT license (https://opensource.org/license/mit/)
+
+//- GENERATED CODE
+
+C_LINKAGE_BEGIN
+C_LINKAGE_END
+