Allow downscaling the resolution of the framebuffer.

fixes #99

assets/cubyz/shaders/deferred_render_pass.fs

@@ -54,7 +54,7 @@ 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);
+	float fogDistance = calculateFogDistance(texture(depthTexture, texCoords).r, fog.density*densityAdjustment);
 	fragColor.rgb = applyFrontfaceFog(fogDistance, fog.color, fragColor.rgb);
 	float maxColor = max(1.0, max(fragColor.r, max(fragColor.g, fragColor.b)));
 	fragColor.rgb = fragColor.rgb/maxColor;

src/gui/windows/graphics.zig

@@ -19,6 +19,8 @@ pub var window = GuiWindow {
 const padding: f32 = 8;
 const renderDistances = [_]u16{4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24};
 
+const resolutions = [_]u16{25, 50, 100};
+
 fn renderDistanceCallback(newValue: u16) void {
 	settings.renderDistance = newValue + renderDistances[0];
 }
@@ -41,12 +43,18 @@ fn anisotropicFilteringCallback(newValue: bool) void {
 	// TODO: Reload the textures.
 }
 
+fn resolutionScaleCallback(newValue: u16) void {
+	settings.resolutionScale = @as(i32, newValue) - 2;
+	main.Window.GLFWCallbacks.framebufferSize(null, main.Window.width, main.Window.height);
+}
+
 pub fn onOpen() void {
 	const list = VerticalList.init(.{padding, 16 + padding}, 300, 16);
 	list.add(DiscreteSlider.init(.{0, 0}, 128, "#ffffffRender Distance: ", "{}", &renderDistances, settings.renderDistance - renderDistances[0], &renderDistanceCallback));
 	list.add(CheckBox.init(.{0, 0}, 128, "Bloom", settings.bloom, &bloomCallback));
 	list.add(CheckBox.init(.{0, 0}, 128, "Vertical Synchronization", settings.vsync, &vsyncCallback));
 	list.add(CheckBox.init(.{0, 0}, 128, "Anisotropic Filtering", settings.anisotropicFiltering, &anisotropicFilteringCallback));
+	list.add(DiscreteSlider.init(.{0, 0}, 128, "#ffffffResolution Scale: ", "{}", &resolutions, @intCast(settings.resolutionScale + 2), &resolutionScaleCallback));
 	list.finish(.center);
 	window.rootComponent = list.toComponent();
 	window.contentSize = window.rootComponent.?.pos() + window.rootComponent.?.size() + @as(Vec2f, @splat(padding));

src/renderer.zig

@@ -113,12 +113,17 @@ var lastWidth: u31 = 0;
 var lastHeight: u31 = 0;
 var lastFov: f32 = 0;
 pub fn updateViewport(width: u31, height: u31, fov: f32) void {
-	lastWidth = width;
+	if(main.settings.resolutionScale < 0) {
-	lastHeight = height;
+		lastWidth = width >> @intCast(-main.settings.resolutionScale);
+		lastHeight = height >> @intCast(-main.settings.resolutionScale);
+	} else {
+		lastWidth = width;
+		lastHeight = height;
+	}
 	lastFov = fov;
-	c.glViewport(0, 0, width, height);
+	c.glViewport(0, 0, lastWidth, lastHeight);
-	game.projectionMatrix = Mat4f.perspective(std.math.degreesToRadians(fov), @as(f32, @floatFromInt(width))/@as(f32, @floatFromInt(height)), zNear, zFar);
+	game.projectionMatrix = Mat4f.perspective(std.math.degreesToRadians(fov), @as(f32, @floatFromInt(lastWidth))/@as(f32, @floatFromInt(lastHeight)), zNear, zFar);
-	worldFrameBuffer.updateSize(width, height, c.GL_RGB16F);
+	worldFrameBuffer.updateSize(lastWidth, lastHeight, c.GL_RGB16F);
 	worldFrameBuffer.unbind();
 }
 
@@ -137,6 +142,7 @@ pub fn render(playerPosition: Vec3d) void {
 		const startTime = std.time.milliTimestamp();
 		mesh_storage.updateMeshes(startTime + maximumMeshTime);
 	} else {
+		c.glViewport(0, 0, main.Window.width, main.Window.height);
 		MenuBackGround.render();
 	}
 }
@@ -166,6 +172,7 @@ pub fn crosshairDirection(rotationMatrix: Mat4f, fovY: f32, width: u31, height:
 
 pub fn renderWorld(world: *World, ambientLight: Vec3f, skyColor: Vec3f, playerPos: Vec3d) void {
 	worldFrameBuffer.bind();
+	c.glViewport(0, 0, lastWidth, lastHeight);
 	gpu_performance_measuring.startQuery(.clear);
 	worldFrameBuffer.clear(Vec4f{skyColor[0], skyColor[1], skyColor[2], 1});
 	gpu_performance_measuring.stopQuery();
@@ -262,6 +269,7 @@ pub fn renderWorld(world: *World, ambientLight: Vec3f, skyColor: Vec3f, playerPo
 		Bloom.bindReplacementImage();
 	}
 	gpu_performance_measuring.startQuery(.final_copy);
+	c.glViewport(0, 0, main.Window.width, main.Window.height);
 	worldFrameBuffer.bindTexture(c.GL_TEXTURE3);
 	worldFrameBuffer.bindDepthTexture(c.GL_TEXTURE4);
 	worldFrameBuffer.unbind();

src/settings.zig

@@ -24,6 +24,8 @@ pub var mouseSensitivity: f32 = 1;
 
 pub var renderDistance: u16 = 7;
 
+pub var resolutionScale: i32 = 0;
+
 pub var bloom: bool = true;
 
 pub var vsync: bool = true;