From 08df9973962f6878498c87be20bbf2d56ee8f1f9 Mon Sep 17 00:00:00 2001
From: Phillip Trudeau-Tavara <pmttavara@protonmail.com>
Date: Wed, 23 Aug 2023 11:26:48 -0400
Subject: [PATCH] Film grain, contrast, vignette, cross-processing

---
 main.c        |  2 ++
 threedee.glsl | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/main.c b/main.c
index e99ce8d..742f930 100644
--- a/main.c
+++ b/main.c
@@ -3758,6 +3758,7 @@ void flush_quad_batch()
 	state.bind.fs.samplers[SLOT_threedee_fs_twodee_smp] = state.sampler_linear; // NOTE that this might get FUCKED if a custom pipeline is provided with more/less sampler slots!!!
 	sg_apply_bindings(&state.bind);
 	cur_batch_params.tex_size = img_size(cur_batch_image);
+	cur_batch_params.screen_size = screen_size();
 	sg_apply_uniforms(SG_SHADERSTAGE_FS, SLOT_threedee_twodee_fs_params, &SG_RANGE(cur_batch_params));
 	cur_batch_params.tex_size = V2(0,0); // unsure if setting the tex_size to something nonzero fucks up the batching so I'm just resetting it back here
 	assert(cur_batch_data_index % FLOATS_PER_VERTEX == 0);
@@ -7100,6 +7101,7 @@ ISANERROR("Don't know how to do this stuff on this platform.")
 						Vec2 *points = d.quad.points;
 						threedee_twodee_fs_params_t params = {
 							.tint = d.tint,
+							.time = (float)fmod(elapsed_time, 100),
 						};
 						params.alpha_clip_threshold = d.alpha_clip_threshold;
 						if (d.do_clipping)
diff --git a/threedee.glsl b/threedee.glsl
index 95947f4..b14245d 100644
--- a/threedee.glsl
+++ b/threedee.glsl
@@ -381,8 +381,10 @@ uniform twodee_fs_params {
     vec2 clip_lr;
 
     float alpha_clip_threshold;
+	float time;
 
 		vec2 tex_size;
+		vec2 screen_size;
 };
 
 in vec2 uv;
@@ -414,8 +416,10 @@ uniform twodee_fs_params {
     vec2 clip_lr;
 
     float alpha_clip_threshold;
+	float time;
 
 		vec2 tex_size;
+		vec2 screen_size;
 };
 
 in vec2 uv;
@@ -470,8 +474,10 @@ uniform twodee_fs_params {
     vec2 clip_lr;
 
     float alpha_clip_threshold;
+	float time;
 
 		vec2 tex_size;
+		vec2 screen_size;
 };
 
 in vec2 uv;
@@ -496,6 +502,24 @@ void main() {
 
 		col.rgb = acesFilm(col.rgb);
 
+		// Film grain
+		vec2 uv = gl_FragCoord.xy / screen_size.xy;
+		float x = uv.x * uv.y * time * 24 + 100.0;
+		vec3 noise = vec3(mod((mod(x, 13.0) + 1.0) * (mod(x, 123.0) + 1.0), 0.01)) * 100.0;
+		col.rgb += (noise - 0.5) * 0.05;
+		col.rgb *= 0.95;
+		// Hard-clip contrast levels
+		float min = 11; float max = 204;
+		col.rgb -= min/255;
+		col.rgb *= 255/(max-min);
+		// Vignette
+		col.rgb *= clamp(1.5 - length(gl_FragCoord.xy / screen_size.xy - vec2(0.5)), 0, 1);
+		// Cross-process
+		float cross_process_strength = 0.5;
+		col.rg *= (col.rg * ((-cross_process_strength) * col.rg + (-1.5 * (-cross_process_strength))) + (0.5 * (-cross_process_strength) + 1));
+		col.b  *= (col.b  * ((+cross_process_strength) * col.b  + (-1.5 * (+cross_process_strength))) + (0.5 * (+cross_process_strength) + 1));
+		col.rgb = clamp(col.rgb, 0, 1);
+
 		frag_color = col;
 }
 @end