rsx: Minor bug fixes

- vk: Do not select first available format when choosing a swapchain format
- gl/vk: Ignore rendering zero sized framebuffers/scissors
- fp: Re-enable range clamp on fp16 registers; fix fx12 clamping [-2, 2]

rpcs3/Emu/RSX/Common/FragmentProgramDecompiler.cpp

@@ -37,13 +37,12 @@ void FragmentProgramDecompiler::SetDst(std::string code, bool append_mask)
 		break;
 	}
 
-	if (dst.saturate)
-	{
-		code = saturate(code);
-	}
-	else if (!dst.no_dest)
+	if (!dst.no_dest)
 	{
 		code = NoOverflow(code);
+
+		if (dst.saturate)
+			code = saturate(code);
 	}
 
 	code += (append_mask ? "$m" : "");
@@ -64,13 +63,6 @@ void FragmentProgramDecompiler::SetDst(std::string code, bool append_mask)
 
 	std::string dest = AddReg(dst.dest_reg, dst.fp16) + "$m";
 
-	if (dst.exp_tex)
-	{
-		//TODO
-		//If exp_tex really sets _bx2 flag, we may need to perform extra modifications to the src
-		AddCode("//TODO: exp tex flag is set");
-	}
-
 	AddCodeCond(Format(dest), code);
 	//AddCode("$ifcond " + dest + code + (append_mask ? "$m;" : ";"));
 
@@ -206,6 +198,7 @@ std::string FragmentProgramDecompiler::NoOverflow(const std::string& code)
 	if (dst.exp_tex)
 	{
 		//If dst.exp_tex really is _bx2 postfix, we need to unpack dynamic range
+		AddCode("//exp tex flag is set");
 		return "((" + code + "- 0.5) * 2.)";
 	}
 
@@ -214,11 +207,9 @@ std::string FragmentProgramDecompiler::NoOverflow(const std::string& code)
 	case 0:
 		break;
 	case 1:
-		//Disabled: Causes blue output in some games such as persona V and soul calibur IV
-		//return "clamp(" + code + ", -65504., 65504.)";
-		break;
+		return "clamp(" + code + ", -65504., 65504.)";
 	case 2:
-		return "clamp(" + code + ", -1., 1.)";
+		return "clamp(" + code + ", -2., 2.)";
 	}
 
 	return code;

rpcs3/Emu/RSX/GL/GLGSRender.cpp

@@ -191,7 +191,7 @@ void GLGSRender::begin()
 
 	init_buffers();
 
-	if (!draw_fbo.check())
+	if (!framebuffer_status_valid)
 		return;
 
 	std::chrono::time_point<steady_clock> then = steady_clock::now();
@@ -322,7 +322,7 @@ namespace
 
 void GLGSRender::end()
 {
-	if (skip_frame || !draw_fbo || !draw_fbo.check())
+	if (skip_frame || !framebuffer_status_valid)
 	{
 		rsx::thread::end();
 		return;
@@ -523,13 +523,26 @@ void GLGSRender::end()
 void GLGSRender::set_viewport()
 {
 	//NOTE: scale offset matrix already contains the viewport transformation
-	glViewport(0, 0, rsx::method_registers.surface_clip_width(), rsx::method_registers.surface_clip_height());
+	const auto clip_width = rsx::method_registers.surface_clip_width();
+	const auto clip_height = rsx::method_registers.surface_clip_height();
+	glViewport(0, 0, clip_width, clip_height);
 
 	u16 scissor_x = rsx::method_registers.scissor_origin_x();
 	u16 scissor_w = rsx::method_registers.scissor_width();
 	u16 scissor_y = rsx::method_registers.scissor_origin_y();
 	u16 scissor_h = rsx::method_registers.scissor_height();
 
+	//Do not bother drawing anything if output is zero sized
+	//TODO: Clip scissor region
+	if (scissor_x >= clip_width || scissor_y >= clip_height || scissor_w == 0 || scissor_h == 0)
+	{
+		if (!g_cfg.video.strict_rendering_mode)
+		{
+			framebuffer_status_valid = false;
+			return;
+		}
+	}
+
 	//NOTE: window origin does not affect scissor region (probably only affects viewport matrix; already applied)
 	//See LIMBO [NPUB-30373] which uses shader window origin = top
 	__glcheck glScissor(scissor_x, scissor_y, scissor_w, scissor_h);
@@ -726,7 +739,7 @@ void GLGSRender::on_exit()
 
 void GLGSRender::clear_surface(u32 arg)
 {
-	if (skip_frame) return;
+	if (skip_frame || !framebuffer_status_valid) return;
 	if (rsx::method_registers.surface_color_target() == rsx::surface_target::none) return;
 	if ((arg & 0xf3) == 0) return;
 

rpcs3/Emu/RSX/GL/GLGSRender.h

@@ -70,6 +70,8 @@ private:
 	std::mutex queue_guard;
 	std::list<work_item> work_queue;
 
+	bool framebuffer_status_valid = false;
+
 	rsx::gcm_framebuffer_info surface_info[rsx::limits::color_buffers_count];
 	rsx::gcm_framebuffer_info depth_surface_info;
 

rpcs3/Emu/RSX/GL/GLRenderTargets.cpp

@@ -165,6 +165,12 @@ void GLGSRender::init_buffers(bool skip_reading)
 	const u16 clip_horizontal = rsx::method_registers.surface_clip_width();
 	const u16 clip_vertical = rsx::method_registers.surface_clip_height();
 
+	if (clip_horizontal == 0 || clip_vertical == 0)
+	{
+		LOG_ERROR(RSX, "Invalid framebuffer setup, w=%d, h=%d", clip_horizontal, clip_vertical);
+		framebuffer_status_valid = false;
+	}
+
 	const auto pitchs = get_pitchs();
 	const auto surface_format = rsx::method_registers.surface_color();
 	const auto depth_format = rsx::method_registers.surface_depth_fmt();
@@ -235,8 +241,8 @@ void GLGSRender::init_buffers(bool skip_reading)
 	else
 		depth_surface_info = {};
 
-	if (!draw_fbo.check())
-		return;
+	framebuffer_status_valid = draw_fbo.check();
+	if (!framebuffer_status_valid) return;
 
 	draw_fbo.bind();
 	set_viewport();

rpcs3/Emu/RSX/VK/VKGSRender.cpp

@@ -838,6 +838,9 @@ void VKGSRender::begin()
 
 	init_buffers();
 
+	if (!framebuffer_status_valid)
+		return;
+
 	float actual_line_width = rsx::method_registers.line_width();
 
 	vkCmdSetLineWidth(*m_current_command_buffer, actual_line_width);
@@ -898,7 +901,7 @@ void VKGSRender::close_render_pass()
 
 void VKGSRender::end()
 {
-	if (skip_frame)
+	if (skip_frame || !framebuffer_status_valid)
 	{
 		rsx::thread::end();
 		return;
@@ -1200,6 +1203,15 @@ void VKGSRender::set_viewport()
 	scissor.offset.y = scissor_y;
 
 	vkCmdSetScissor(*m_current_command_buffer, 0, 1, &scissor);
+
+	if (scissor_x >= viewport.width || scissor_y >= viewport.height || scissor_w == 0 || scissor_h == 0)
+	{
+		if (!g_cfg.video.strict_rendering_mode)
+		{
+			framebuffer_status_valid = false;
+			return;
+		}
+	}
 }
 
 void VKGSRender::on_init_thread()
@@ -1229,6 +1241,9 @@ void VKGSRender::clear_surface(u32 mask)
 	if (m_current_present_image == 0xFFFF) return;
 
 	init_buffers();
+
+	if (!framebuffer_status_valid) return;
+
 	copy_render_targets_to_dma_location();
 
 	float depth_clear = 1.f;
@@ -1834,6 +1849,14 @@ void VKGSRender::prepare_rtts()
 	u32 clip_x = rsx::method_registers.surface_clip_origin_x();
 	u32 clip_y = rsx::method_registers.surface_clip_origin_y();
 
+	if (clip_width == 0 || clip_height == 0)
+	{
+		LOG_ERROR(RSX, "Invalid framebuffer setup, w=%d, h=%d", clip_width, clip_height);
+		framebuffer_status_valid = false;
+	}
+
+	framebuffer_status_valid = true;
+
 	auto surface_addresses = get_color_surface_addresses();
 	auto zeta_address = get_zeta_surface_address();
 	

rpcs3/Emu/RSX/VK/VKGSRender.h

@@ -167,6 +167,8 @@ private:
 	u32 m_used_descriptors = 0;
 	u8 m_draw_buffers_count = 0;
 
+	bool framebuffer_status_valid = false;
+
 	rsx::gcm_framebuffer_info m_surface_info[rsx::limits::color_buffers_count];
 	rsx::gcm_framebuffer_info m_depth_surface_info;
 

rpcs3/Emu/RSX/VK/VKHelpers.h

@@ -1293,6 +1293,16 @@ namespace vk
 			{
 				if (!formatCount) fmt::throw_exception("Format count is zero!" HERE);
 				format = surfFormats[0].format;
+
+				//Prefer BGRA8_UNORM to avoid sRGB compression (RADV)
+				for (auto& surface_format: surfFormats)
+				{
+					if (surface_format.format == VK_FORMAT_B8G8R8A8_UNORM)
+					{
+						format = VK_FORMAT_B8G8R8A8_UNORM;
+						break;
+					}
+				}
 			}
 
 			color_space = surfFormats[0].colorSpace;