From 111b5c54691f5886a7283fbbe1fe8cfe7ba97bbb Mon Sep 17 00:00:00 2001
From: Magnus Norddahl <dpjudas@users.noreply.github.com>
Date: Thu, 19 Jan 2017 00:12:54 +0100
Subject: [PATCH] Add support for repeating skies in the TC sky drawer

---
 src/swrenderer/drawers/r_draw_rgba.cpp        |  1 +
 src/swrenderer/drawers/r_drawers.h            |  5 ++++
 .../fixedfunction/drawskycodegen.cpp          | 23 +++++++++++++++----
 .../drawergen/fixedfunction/drawskycodegen.h  |  4 +++-
 tools/drawergen/llvmdrawers.cpp               |  2 +-
 5 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/src/swrenderer/drawers/r_draw_rgba.cpp b/src/swrenderer/drawers/r_draw_rgba.cpp
index a520d28ae..fcf94e5da 100644
--- a/src/swrenderer/drawers/r_draw_rgba.cpp
+++ b/src/swrenderer/drawers/r_draw_rgba.cpp
@@ -329,6 +329,7 @@ namespace swrenderer
 		args.textureheight1 = dc_wall_sourceheight[1];
 		args.top_color = solid_top;
 		args.bottom_color = solid_bottom;
+		args.flags = fadeSky ? DrawSkyArgs::fade_sky : 0;
 
 		DetectRangeError(args.dest, args.dest_y, args.count);
 	}
diff --git a/src/swrenderer/drawers/r_drawers.h b/src/swrenderer/drawers/r_drawers.h
index 0492930d9..2d251478c 100644
--- a/src/swrenderer/drawers/r_drawers.h
+++ b/src/swrenderer/drawers/r_drawers.h
@@ -200,6 +200,11 @@ struct DrawSkyArgs
 	uint32_t textureheight1;
 	uint32_t top_color;
 	uint32_t bottom_color;
+	uint32_t flags;
+	enum Flags
+	{
+		fade_sky = 1
+	};
 
 	FString ToString();
 };
diff --git a/tools/drawergen/fixedfunction/drawskycodegen.cpp b/tools/drawergen/fixedfunction/drawskycodegen.cpp
index 3bd23e529..9fdd33a17 100644
--- a/tools/drawergen/fixedfunction/drawskycodegen.cpp
+++ b/tools/drawergen/fixedfunction/drawskycodegen.cpp
@@ -47,12 +47,15 @@ void DrawSkyCodegen::Generate(DrawSkyVariant variant, SSAValue args, SSAValue th
 	maxtextureheight1 = textureheight1 - 1;
 	top_color = SSAVec4i::unpack(args[0][22].load(true));
 	bottom_color = SSAVec4i::unpack(args[0][23].load(true));
+	SSAInt flags = args[0][24].load(true);
 
 	thread.core = thread_data[0][0].load(true);
 	thread.num_cores = thread_data[0][1].load(true);
 	thread.pass_start_y = thread_data[0][2].load(true);
 	thread.pass_end_y = thread_data[0][3].load(true);
 
+	is_fade_sky = (flags & DrawSkyArgs::fade_sky) == SSAInt(DrawSkyArgs::fade_sky);
+
 	count = count_for_thread(dest_y, count, thread);
 	dest = dest_for_thread(dest_y, pitch, dest, thread);
 
@@ -61,10 +64,15 @@ void DrawSkyCodegen::Generate(DrawSkyVariant variant, SSAValue args, SSAValue th
 	stack_frac.store(texturefrac + iscale * skipped_by_thread(dest_y, thread));
 	fracstep = iscale * thread.num_cores;
 
-	Loop(variant);
+	SSAIfBlock branch;
+	branch.if_block(is_fade_sky);
+	Loop(variant, true);
+	branch.else_block();
+	Loop(variant, false);
+	branch.end_block();
 }
 
-void DrawSkyCodegen::Loop(DrawSkyVariant variant)
+void DrawSkyCodegen::Loop(DrawSkyVariant variant, bool fade_sky)
 {
 	stack_index.store(SSAInt(0));
 	{
@@ -76,8 +84,15 @@ void DrawSkyCodegen::Loop(DrawSkyVariant variant)
 
 		SSAInt offset = index * pitch * 4;
 
-		SSAVec4i color = FadeOut(frac, Sample(frac, variant));
-		dest[offset].store_vec4ub(color);
+		if (fade_sky)
+		{
+			SSAVec4i color = FadeOut(frac, Sample(frac, variant));
+			dest[offset].store_vec4ub(color);
+		}
+		else
+		{
+			dest[offset].store_vec4ub(Sample(frac, variant));
+		}
 
 		stack_index.store(index.add(SSAInt(1), true, true));
 		stack_frac.store(frac + fracstep);
diff --git a/tools/drawergen/fixedfunction/drawskycodegen.h b/tools/drawergen/fixedfunction/drawskycodegen.h
index 6cd700203..463c8ca23 100644
--- a/tools/drawergen/fixedfunction/drawskycodegen.h
+++ b/tools/drawergen/fixedfunction/drawskycodegen.h
@@ -36,7 +36,7 @@ public:
 	void Generate(DrawSkyVariant variant, SSAValue args, SSAValue thread_data);
 
 private:
-	void Loop(DrawSkyVariant variant);
+	void Loop(DrawSkyVariant variant, bool fade_sky);
 	SSAVec4i Sample(SSAInt frac, DrawSkyVariant variant);
 	SSAVec4i FadeOut(SSAInt frac, SSAVec4i color);
 
@@ -57,4 +57,6 @@ private:
 	SSAWorkerThread thread;
 
 	SSAInt fracstep;
+
+	SSABool is_fade_sky;
 };
diff --git a/tools/drawergen/llvmdrawers.cpp b/tools/drawergen/llvmdrawers.cpp
index 995b5b849..782259702 100644
--- a/tools/drawergen/llvmdrawers.cpp
+++ b/tools/drawergen/llvmdrawers.cpp
@@ -280,7 +280,7 @@ llvm::Type *LLVMDrawers::GetDrawSkyArgsStruct(llvm::LLVMContext &context)
 	elements.push_back(llvm::Type::getInt8PtrTy(context));
 	for (int i = 0; i < 8; i++)
 		elements.push_back(llvm::Type::getInt8PtrTy(context));
-	for (int i = 0; i < 15; i++)
+	for (int i = 0; i < 16; i++)
 		elements.push_back(llvm::Type::getInt32Ty(context));
 	DrawSkyArgsStruct = llvm::StructType::create(context, elements, "DrawSkyArgs", false)->getPointerTo();
 	return DrawSkyArgsStruct;