Cleanup

paint/shaders/bloom_downsample_pass.kong

@@ -0,0 +1,74 @@
+
+#[set(everything)]
+const constants: {
+	screen_size_inv: float2;
+	current_mip_level: int;
+};
+
+#[set(everything)]
+const sampler_linear: sampler;
+
+#[set(everything)]
+const tex: tex2d;
+
+struct vert_in {
+	pos: float2;
+}
+
+struct vert_out {
+	pos: float4;
+	tex: float2;
+}
+
+const bloom_knee: float = 0.5;
+const bloom_threshold: float = 0.8;
+const epsilon: float = 0.000062;
+
+fun bloom_downsample_pass_vert(input: vert_in): vert_out {
+	var output: vert_out;
+	output.tex = input.pos.xy * 0.5 + 0.5;
+	output.tex.y = 1.0 - output.tex.y;
+	output.pos = float4(input.pos.xy, 0.0, 1.0);
+	return output;
+}
+
+fun downsample_dual_filter(tex_coord: float2, texel_size: float2): float3 {
+	var delta: float3 = float3(texel_size.xy, texel_size.x) * float3(0.5, 0.5, -0.5);
+
+	var result: float3;
+	result  = sample_lod(tex, sampler_linear, tex_coord,            0.0).rgb * 4.0;
+	result += sample_lod(tex, sampler_linear, tex_coord - delta.xy, 0.0).rgb;
+	result += sample_lod(tex, sampler_linear, tex_coord - delta.zy, 0.0).rgb;
+	result += sample_lod(tex, sampler_linear, tex_coord + delta.zy, 0.0).rgb;
+	result += sample_lod(tex, sampler_linear, tex_coord + delta.xy, 0.0).rgb;
+
+	return result * (1.0 / 8.0);
+}
+
+fun bloom_downsample_pass_frag(input: vert_out): float4 {
+	var color: float4;
+	color.rgb = downsample_dual_filter(input.tex, constants.screen_size_inv);
+
+	if (constants.current_mip_level == 0) {
+		var brightness: float = max(color.r, max(color.g, color.b));
+
+		var softening_curve: float = brightness - bloom_threshold + bloom_knee;
+		softening_curve = clamp(softening_curve, 0.0, 2.0 * bloom_knee);
+		softening_curve = softening_curve * softening_curve / (4.0 * bloom_knee + epsilon);
+
+		var contribution_factor: float = max(softening_curve, brightness - bloom_threshold);
+
+		contribution_factor /= max(epsilon, brightness);
+
+		color.rgb = color.rgb * contribution_factor;
+	}
+
+	color.a = 1.0;
+	return color;
+}
+
+#[pipe]
+struct pipe {
+	vertex = bloom_downsample_pass_vert;
+	fragment = bloom_downsample_pass_frag;
+}