Merge the functionality of the bloom upscale shader into the final post processing shader.

Increases performance by ~300 µs per frame.
Fixes #97

assets/cubyz/shaders/bloom/upscale.fs

@@ -1,11 +0,0 @@
-#version 430
-
-layout(location=0) out vec4 fragColor;
-
-in vec2 texCoords;
-
-layout(binding = 3) uniform sampler2D color;
-
-void main() {
-	fragColor = vec4(texture(color, texCoords).rgb, 0);
-}

assets/cubyz/shaders/bloom/upscale.vs

@@ -1,10 +0,0 @@
-#version 430
-
-layout (location=0)  in vec2 inTexCoords;
-
-out vec2 texCoords;
-
-void main() {
-	texCoords = inTexCoords;
-	gl_Position = vec4(inTexCoords*2 - vec2(1, 1), 0, 1);
-}

assets/cubyz/shaders/deferred_render_pass.fs

@@ -10,6 +10,8 @@ uniform float zNear;
 uniform float zFar;
 uniform vec2 tanXY;
 
+layout(binding = 5) uniform sampler2D bloomColor;
+
 struct Fog {
 	vec3 color;
 	float density;
@@ -51,6 +53,7 @@ vec3 applyFrontfaceFog(float fogDistance, vec3 fogColor, vec3 inColor) {
 
 void main() {
 	fragColor = texture(color, texCoords);
+	fragColor += texture(bloomColor, texCoords);
 	float densityAdjustment = sqrt(dot(tanXY*(texCoords*2 - 1), tanXY*(texCoords*2 - 1)) + 1);
 	float fogDistance = calculateFogDistance(texelFetch(depthTexture, ivec2(gl_FragCoord.xy), 0).r, fog.density*densityAdjustment);
 	fragColor.rgb = applyFrontfaceFog(fogDistance, fog.color, fragColor.rgb);

src/graphics.zig

@@ -1533,7 +1533,7 @@ pub const Texture = struct {
 		const self = Texture.init();
 		const image = try Image.readFromFile(main.threadAllocator, path);
 		defer image.deinit(main.threadAllocator);
-		try self.generate(image);
+		self.generate(image);
 		return self;
 	}
 
@@ -1551,7 +1551,7 @@ pub const Texture = struct {
 	}
 
 	/// (Re-)Generates the GPU buffer.
-	pub fn generate(self: Texture, image: Image) !void {
+	pub fn generate(self: Texture, image: Image) void {
 		self.bind();
 
 		c.glTexImage2D(c.GL_TEXTURE_2D, 0, c.GL_RGBA8, image.width, image.height, 0, c.GL_RGBA, c.GL_UNSIGNED_BYTE, image.imageData.ptr);
@@ -1669,6 +1669,14 @@ pub const Image = struct {
 		.height = 2,
 		.imageData = &defaultImageData,
 	};
+	var emptyImageData = [1]Color {
+		Color{.r=0, .g=0, .b=0, .a=0},
+	};
+	pub const emptyImage = Image {
+		.width = 1,
+		.height = 1,
+		.imageData = &emptyImageData,
+	};
 	width: u31,
 	height: u31,
 	imageData: []Color,

src/gui/windows/gpu_performance_measuring.zig

@@ -23,7 +23,6 @@ pub const Samples = enum(u8) {
 	bloom_extract_downsample,
 	bloom_first_pass,
 	bloom_second_pass,
-	bloom_upscale,
 	final_copy,
 	gui,
 };
@@ -39,7 +38,6 @@ const names = [_][]const u8 {
 	"Bloom - Extract color and downsample",
 	"Bloom - First Pass",
 	"Bloom - Second Pass",
-	"Bloom - Upscale",
 	"Copy to screen",
 	"GUI Rendering",
 };

src/items.zig

@@ -121,7 +121,7 @@ pub const BaseItem = struct {
 				self.texture = try graphics.generateBlockTexture(blockType);
 			} else {
 				self.texture = graphics.Texture.init();
-				try self.texture.?.generate(self.image);
+				self.texture.?.generate(self.image);
 			}
 		}
 		return self.texture.?;
@@ -998,7 +998,7 @@ pub const Tool = struct {
 	fn getTexture(self: *Tool) !graphics.Texture {
 		if(self.texture == null) {
 			self.texture = graphics.Texture.init();
-			try self.texture.?.generate(self.image);
+			self.texture.?.generate(self.image);
 		}
 		return self.texture.?;
 	}

src/renderer.zig

@@ -271,6 +271,8 @@ pub fn renderWorld(world: *World, ambientLight: Vec3f, skyColor: Vec3f, playerPo
 	
 	if(settings.bloom) {
 		Bloom.render(lastWidth, lastHeight, playerBlock);
+	} else {
+		Bloom.bindReplacementImage();
 	}
 	gpu_performance_measuring.startQuery(.final_copy);
 	worldFrameBuffer.bindTexture(c.GL_TEXTURE3);
@@ -314,12 +316,12 @@ pub fn renderWorld(world: *World, ambientLight: Vec3f, skyColor: Vec3f, playerPo
 const Bloom = struct {
 	var buffer1: graphics.FrameBuffer = undefined;
 	var buffer2: graphics.FrameBuffer = undefined;
+	var emptyBuffer: graphics.Texture = undefined;
 	var width: u31 = std.math.maxInt(u31);
 	var height: u31 = std.math.maxInt(u31);
 	var firstPassShader: graphics.Shader = undefined;
 	var secondPassShader: graphics.Shader = undefined;
 	var colorExtractAndDownsampleShader: graphics.Shader = undefined;
-	var upscaleShader: graphics.Shader = undefined;
 	var colorExtractUniforms: struct {
 		depthTexture: c_int,
 		zNear: c_int,
@@ -332,10 +334,11 @@ const Bloom = struct {
 	pub fn init() !void {
 		buffer1.init(false, c.GL_LINEAR, c.GL_CLAMP_TO_EDGE);
 		buffer2.init(false, c.GL_LINEAR, c.GL_CLAMP_TO_EDGE);
+		emptyBuffer = graphics.Texture.init();
+		emptyBuffer.generate(graphics.Image.emptyImage);
 		firstPassShader = try graphics.Shader.init("assets/cubyz/shaders/bloom/first_pass.vs", "assets/cubyz/shaders/bloom/first_pass.fs");
 		secondPassShader = try graphics.Shader.init("assets/cubyz/shaders/bloom/second_pass.vs", "assets/cubyz/shaders/bloom/second_pass.fs");
 		colorExtractAndDownsampleShader = try graphics.Shader.initAndGetUniforms("assets/cubyz/shaders/bloom/color_extractor_downsample.vs", "assets/cubyz/shaders/bloom/color_extractor_downsample.fs", &colorExtractUniforms);
-		upscaleShader = try graphics.Shader.init("assets/cubyz/shaders/bloom/upscale.vs", "assets/cubyz/shaders/bloom/upscale.fs");
 	}
 
 	pub fn deinit() void {
@@ -343,7 +346,6 @@ const Bloom = struct {
 		buffer2.deinit();
 		firstPassShader.deinit();
 		secondPassShader.deinit();
-		upscaleShader.deinit();
 	}
 
 	fn extractImageDataAndDownsample(playerBlock: blocks.Block) void {
@@ -383,15 +385,7 @@ const Bloom = struct {
 		c.glDrawArrays(c.GL_TRIANGLE_STRIP, 0, 4);
 	}
 
-	fn upscale() void {
+	fn render(currentWidth: u31, currentHeight: u31, playerBlock: blocks.Block) void {
-		upscaleShader.bind();
-		buffer1.bindTexture(c.GL_TEXTURE3);
-		worldFrameBuffer.bind();
-		c.glBindVertexArray(graphics.draw.rectVAO);
-		c.glDrawArrays(c.GL_TRIANGLE_STRIP, 0, 4);
-	}
-
-	pub fn render(currentWidth: u31, currentHeight: u31, playerBlock: blocks.Block) void {
 		if(width != currentWidth or height != currentHeight) {
 			width = currentWidth;
 			height = currentHeight;
@@ -413,11 +407,9 @@ const Bloom = struct {
 		gpu_performance_measuring.stopQuery();
 		gpu_performance_measuring.startQuery(.bloom_second_pass);
 		secondPass();
-		gpu_performance_measuring.stopQuery();
+
-		gpu_performance_measuring.startQuery(.bloom_upscale);
 		c.glViewport(0, 0, width, height);
-		c.glBlendFunc(c.GL_ONE, c.GL_ONE);
+		buffer1.bindTexture(c.GL_TEXTURE5);
-		upscale();
 
 		c.glDepthMask(c.GL_TRUE);
 		c.glEnable(c.GL_DEPTH_TEST);
@@ -425,6 +417,10 @@ const Bloom = struct {
 		c.glBlendFunc(c.GL_SRC_ALPHA, c.GL_ONE_MINUS_SRC_ALPHA);
 		gpu_performance_measuring.stopQuery();
 	}
+
+	fn bindReplacementImage() void {
+		emptyBuffer.bindTo(5);
+	}
 };
 
 pub const MenuBackGround = struct {