From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 12 Dec 2021 21:44:04 +0000 (+0200)
Subject: Refactor handling of viewport Y axis
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=b0db98d71aeb32d9e57315b8a06ff4068aeccbca;p=libs%2Fgl.git

Refactor handling of viewport Y axis

Only invert it for the swapchain render target.  This makes it easier to
sample render target textures consistently.
---

diff --git a/source/backends/vulkan/camera_backend.cpp b/source/backends/vulkan/camera_backend.cpp
index 9eba4289..10e294f7 100644
--- a/source/backends/vulkan/camera_backend.cpp
+++ b/source/backends/vulkan/camera_backend.cpp
@@ -7,7 +7,6 @@ namespace GL {
 void VulkanCamera::adjust_projection_matrix(Matrix &proj_matrix)
 {
 	Matrix adjust;
-	adjust(1, 1) = -1.0f;
 	adjust(2, 2) = 0.5f;
 	adjust(2, 3) = 0.5f;
 	proj_matrix = adjust*proj_matrix;
diff --git a/source/backends/vulkan/commands_backend.cpp b/source/backends/vulkan/commands_backend.cpp
index 643710d5..9c074c87 100644
--- a/source/backends/vulkan/commands_backend.cpp
+++ b/source/backends/vulkan/commands_backend.cpp
@@ -81,14 +81,14 @@ void VulkanCommands::begin_render_pass(bool clear, const ClearValue *clear_value
 	Synchronizer &sync = device.get_synchronizer();
 	sync.reset();
 
-	bool to_present = false;
+	fb_is_swapchain = false;
 	unsigned n_attachments = framebuffer->get_format().size();
-	for(unsigned i=0; i<n_attachments; ++i)
+	for(unsigned i=0; (!fb_is_swapchain && i<n_attachments); ++i)
 		if(dynamic_cast<const SwapChainTexture *>(framebuffer->get_attachment(i)))
-			to_present = true;
-	if(!to_present)
+			fb_is_swapchain = true;
+	if(!fb_is_swapchain)
 		framebuffer->prepare_image_layouts(clear && !viewport);
-	VkRenderPass render_pass = device.get_pipeline_cache().get_render_pass(framebuffer->get_format(), clear, (!clear_values && !viewport), to_present);
+	VkRenderPass render_pass = device.get_pipeline_cache().get_render_pass(framebuffer->get_format(), clear, (!clear_values && !viewport), fb_is_swapchain);
 
 	framebuffer->refresh();
 
@@ -102,7 +102,7 @@ void VulkanCommands::begin_render_pass(bool clear, const ClearValue *clear_value
 	if(viewport)
 	{
 		begin_info.renderArea.offset.x = viewport->left;
-		begin_info.renderArea.offset.y = framebuffer->get_height()-(viewport->bottom+viewport->height);
+		begin_info.renderArea.offset.y = viewport->bottom;
 		begin_info.renderArea.extent.width = viewport->width;
 		begin_info.renderArea.extent.height = viewport->height;
 	}
@@ -233,7 +233,7 @@ void VulkanCommands::draw_instanced(const Batch &batch, unsigned count)
 		 begin_render_pass(false, 0);
 
 	pipeline_state->refresh();
-	pipeline_state->apply(current_buffer);
+	pipeline_state->apply(current_buffer, fb_is_swapchain);
 	unsigned first_index = batch.get_offset()/batch.get_index_size();
 	vk.CmdDrawIndexed(current_buffer, batch.size(), count, first_index, 0, 0);
 }
diff --git a/source/backends/vulkan/commands_backend.h b/source/backends/vulkan/commands_backend.h
index a89225a6..994acca2 100644
--- a/source/backends/vulkan/commands_backend.h
+++ b/source/backends/vulkan/commands_backend.h
@@ -42,6 +42,7 @@ protected:
 	const PipelineState *pipeline_state = 0;
 	const Framebuffer *framebuffer = 0;
 	const Rect *viewport = 0;
+	bool fb_is_swapchain = false;
 
 	VulkanCommands();
 	~VulkanCommands();
diff --git a/source/backends/vulkan/pipelinestate_backend.cpp b/source/backends/vulkan/pipelinestate_backend.cpp
index 419a7e4c..a1a03d3d 100644
--- a/source/backends/vulkan/pipelinestate_backend.cpp
+++ b/source/backends/vulkan/pipelinestate_backend.cpp
@@ -356,7 +356,7 @@ unsigned VulkanPipelineState::fill_descriptor_writes(unsigned index, vector<char
 	return n_writes;
 }
 
-void VulkanPipelineState::apply(VkCommandBuffer command_buffer) const
+void VulkanPipelineState::apply(VkCommandBuffer command_buffer, bool negative_viewport) const
 {
 	const PipelineState &self = *static_cast<const PipelineState *>(this);
 	const VulkanFunctions &vk = device.get_functions();
@@ -387,7 +387,7 @@ void VulkanPipelineState::apply(VkCommandBuffer command_buffer) const
 	if(self.viewport)
 	{
 		viewport.x = self.viewport->left;
-		viewport.y = self.framebuffer->get_height()-(self.viewport->bottom+self.viewport->height);
+		viewport.y = self.viewport->bottom;
 		viewport.width = self.viewport->width;
 		viewport.height = self.viewport->height;
 	}
@@ -398,6 +398,11 @@ void VulkanPipelineState::apply(VkCommandBuffer command_buffer) const
 		viewport.width = self.framebuffer->get_width();
 		viewport.height = self.framebuffer->get_height();
 	}
+	if(negative_viewport)
+	{
+		viewport.y += viewport.height;
+		viewport.height = -viewport.height;
+	}
 	viewport.minDepth = 0.0f;
 	viewport.maxDepth = 1.0f;
 	vk.CmdSetViewport(command_buffer, 0, 1, &viewport);
@@ -406,7 +411,7 @@ void VulkanPipelineState::apply(VkCommandBuffer command_buffer) const
 	if(self.scissor)
 	{
 		scissor.offset.x = self.scissor->left;
-		scissor.offset.y = self.framebuffer->get_height()-(self.scissor->bottom+self.scissor->height);
+		scissor.offset.y = self.scissor->bottom;
 		scissor.extent.width = self.scissor->width;
 		scissor.extent.height = self.scissor->height;
 	}
diff --git a/source/backends/vulkan/pipelinestate_backend.h b/source/backends/vulkan/pipelinestate_backend.h
index e675ff33..19f7f902 100644
--- a/source/backends/vulkan/pipelinestate_backend.h
+++ b/source/backends/vulkan/pipelinestate_backend.h
@@ -33,7 +33,7 @@ protected:
 	VkDescriptorSetLayout get_descriptor_set_layout(unsigned) const;
 	unsigned fill_descriptor_writes(unsigned, std::vector<char> &) const;
 
-	void apply(VkCommandBuffer) const;
+	void apply(VkCommandBuffer, bool) const;
 };
 
 using PipelineStateBackend = VulkanPipelineState;