From 16128826a4e6909dcd4ef7812b066fea8f5f24f0 Mon Sep 17 00:00:00 2001
From: klemek <klemek.dev@proton.me>
Date: Tue, 16 Sep 2025 23:23:53 +0200
Subject: [PATCH] mix stage

---
 shaders/frag0.glsl | 26 +++++++++++++++++++++++++-
 shaders/frag5.glsl |  3 +--
 src/shaders.c      | 16 ++++++++--------
 src/types.h        |  3 +--
 4 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/shaders/frag0.glsl b/shaders/frag0.glsl
index 3aabb93..85d8bfd 100644
--- a/shaders/frag0.glsl
+++ b/shaders/frag0.glsl
@@ -919,4 +919,28 @@ subroutine(fx_stage_sub) vec3 fx_2(vec2 vUV, sampler2D previous, sampler2D feedb
 // 7. mix
 // ----------
 
-// TODO
\ No newline at end of file
+subroutine vec3 mix_stage_sub(vec2 vUV, sampler2D frame_a, sampler2D frame_b);
+
+subroutine uniform mix_stage_sub mix_stage;
+
+subroutine(mix_stage_sub) vec3 mix_0(vec2 vUV, sampler2D fa, sampler2D fb)
+{
+    float v = 0.5;
+
+    vec3 color_a = texture(fa, vUV).xyz;
+    vec3 color_b = texture(fb, vUV).xyz;
+
+    return mix(color_b, color_a, v);
+}
+
+subroutine(mix_stage_sub) vec3 mix_1(vec2 vUV, sampler2D fa, sampler2D fb)
+{
+    float v = 0.5;
+
+    vec3 color_a = texture(fa, vUV).xyz;
+    vec3 color_b = texture(fb, vUV).xyz;
+
+    float k = mean(color_a);
+
+    return mix(color_b, color_a, step(v, k));
+}
\ No newline at end of file
diff --git a/shaders/frag5.glsl b/shaders/frag5.glsl
index 3576ce3..ee1da15 100644
--- a/shaders/frag5.glsl
+++ b/shaders/frag5.glsl
@@ -8,6 +8,5 @@ in vec2 vUV;
 layout(location = 7) out vec3 fragColor;
 
 void main() {
-    // TODO subroutine
-    fragColor = texture(frame5, vUV).xyz + texture(frame6, vUV).xyz;
+    fragColor = mix_stage(vUV, frame5, frame6);
 }
\ No newline at end of file
diff --git a/src/shaders.c b/src/shaders.c
index 3467b6d..3d53509 100644
--- a/src/shaders.c
+++ b/src/shaders.c
@@ -151,19 +151,18 @@ void init_single_program(ShaderProgram *program, int i, bool output) {
     program->ires_locations[i] =
         glGetUniformLocation(program->programs[i], "iResolution");
 
-    program->sub_src_locations[i] = glGetSubroutineUniformLocation(
-        program->programs[i], GL_FRAGMENT_SHADER, "src_stage");
-    program->sub_fx_locations[i] = glGetSubroutineUniformLocation(
-        program->programs[i], GL_FRAGMENT_SHADER, "fx_stage");
-
     for (j = 0; j < SUB_COUNT; j++) {
       sprintf(name, "src_%d", j);
       program->sub_src_indexes[i][j] =
           glGetSubroutineIndex(program->programs[i], GL_FRAGMENT_SHADER, name);
-      log_debug("%s %d", name, program->sub_src_indexes[i][j]);
       sprintf(name, "fx_%d", j);
       program->sub_fx_indexes[i][j] =
           glGetSubroutineIndex(program->programs[i], GL_FRAGMENT_SHADER, name);
+      if (j < 2) {
+        sprintf(name, "mix_%d", j);
+        program->sub_mix_indexes[i][j] = glGetSubroutineIndex(
+            program->programs[i], GL_FRAGMENT_SHADER, name);
+      }
     }
   }
 
@@ -233,7 +232,7 @@ void update_program(ShaderProgram program, File *fragment_shaders, int i) {
 
 void apply_program(ShaderProgram program, Context context) {
   int i, j;
-  GLuint subroutines[2];
+  GLuint subroutines[3];
 
   // viewport changed
   if (context.width != program.last_width ||
@@ -275,8 +274,9 @@ void apply_program(ShaderProgram program, Context context) {
       // TODO tmp
       subroutines[0] = program.sub_src_indexes[i][i == 0 ? 1 : 2];
       subroutines[1] = program.sub_fx_indexes[i][i == 2 ? 1 : 0];
+      subroutines[2] = program.sub_mix_indexes[i][1];
 
-      glUniformSubroutinesuiv(GL_FRAGMENT_SHADER, 2, subroutines);
+      glUniformSubroutinesuiv(GL_FRAGMENT_SHADER, 3, subroutines);
     }
 
     // set GL_TEXTURE(X) to uniform sampler2D frameX
diff --git a/src/types.h b/src/types.h
index d0194f2..a8b21e6 100644
--- a/src/types.h
+++ b/src/types.h
@@ -47,10 +47,9 @@ typedef struct ShaderProgram {
 
   GLuint frames_locations[FRAG_COUNT + 1][TEX_COUNT];
 
-  GLuint sub_src_locations[FRAG_COUNT];
   GLuint sub_src_indexes[FRAG_COUNT][SUB_COUNT];
-  GLuint sub_fx_locations[FRAG_COUNT];
   GLuint sub_fx_indexes[FRAG_COUNT][SUB_COUNT];
+  GLuint sub_mix_indexes[FRAG_COUNT][2];
 
   GLuint vpos_locations[FRAG_COUNT + 1];