From a6de61f475b231bf1bb8ec0cd5a0af10c7c7a896 Mon Sep 17 00:00:00 2001
From: Martijn Braam <martijn@brixit.nl>
Date: Wed, 16 Aug 2023 14:45:57 +0200
Subject: [PATCH] Implement whitebalance

---
 data/debayer.frag      |  1 -
 src/io_pipeline.c      |  3 ++-
 src/main.c             |  6 ++++--
 src/process_pipeline.c | 29 +++++++++++++++++++++++------
 4 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/data/debayer.frag b/data/debayer.frag
index ede66a3..d0900e3 100644
--- a/data/debayer.frag
+++ b/data/debayer.frag
@@ -61,7 +61,6 @@ main()
 #endif
 
         color -= blacklevel;
-        color *= 1.0-(1.0/blacklevel);
         color *= color_matrix;
 
         vec3 gamma_color = pow(color, vec3(inv_gamma));
diff --git a/src/io_pipeline.c b/src/io_pipeline.c
index 6e7445f..5002c67 100644
--- a/src/io_pipeline.c
+++ b/src/io_pipeline.c
@@ -532,7 +532,8 @@ update_state(MPPipeline *pipeline, const mp_state_io *new_state)
                 state_io.flash_enabled = new_state->flash_enabled;
 
                 state_io.stats.exposure = new_state->stats.exposure;
-                state_io.stats.whitebalance = new_state->stats.whitebalance;
+                state_io.stats.temp = new_state->stats.temp;
+                state_io.stats.tint = new_state->stats.tint;
                 state_io.stats.focus = new_state->stats.focus;
         }
 
diff --git a/src/main.c b/src/main.c
index 5c492a2..9353603 100644
--- a/src/main.c
+++ b/src/main.c
@@ -133,7 +133,8 @@ update_io_pipeline()
                 .focus.manual_req = state.focus.manual_req,
 
                 .stats.exposure = state.stats.exposure,
-                .stats.whitebalance = state.stats.whitebalance,
+                .stats.temp = state.stats.temp,
+                .stats.tint = state.stats.tint,
                 .stats.focus = state.stats.focus,
         };
         mp_io_pipeline_update_state(&new_state);
@@ -171,7 +172,8 @@ update_state(const mp_state_main *new_state)
         state.preview_buffer_height = new_state->preview_buffer_height;
 
         state.stats.exposure = new_state->stats.exposure;
-        state.stats.whitebalance = new_state->stats.whitebalance;
+        state.stats.temp = new_state->stats.temp;
+        state.stats.tint = new_state->stats.tint;
         state.stats.focus = new_state->stats.focus;
 
         // Make the right settings available for the camera
diff --git a/src/process_pipeline.c b/src/process_pipeline.c
index b4b3f66..028e5c7 100644
--- a/src/process_pipeline.c
+++ b/src/process_pipeline.c
@@ -388,6 +388,17 @@ mp_process_pipeline_init_gl(GdkSurface *surface)
                            sizeof(GdkSurface *));
 }
 
+float
+clamp_float(float value, float min, float max) {
+        if(value > max)
+                return max;
+
+        if(value < min)
+                return min;
+
+        return value;
+}
+
 static GdkTexture *
 process_image_for_preview(const uint8_t *image)
 {
@@ -461,10 +472,10 @@ process_image_for_preview(const uint8_t *image)
         mp_main_set_preview(output_buffer);
 
         if (!state_proc.exposure.manual && state_proc.exposure.auto_control == 0) {
-                int width = output_buffer_width / 3;
+                int width = output_buffer_width;
                 int height = output_buffer_height / 3;
                 uint32_t *center = g_malloc_n(width * height * sizeof(uint32_t), 1);
-                glReadPixels(width,
+                glReadPixels(0,
                              height,
                              width,
                              height,
@@ -474,9 +485,14 @@ process_image_for_preview(const uint8_t *image)
                 libmegapixels_aaa_software_statistics(
                         center, width, height, &state_proc.stats);
 
-                state_proc.red += (state_proc.stats.whitebalance * -0.02f) + (state_proc.stats.tint * 0.01f);
-                state_proc.blue += (state_proc.stats.whitebalance * +0.02f) + (state_proc.stats.tint * 0.01f);
-                state_proc.blacklevel += state_proc.stats.blacklevel * 0.01f;
+		float w_gain = 0.02f;
+		float t_gain = 0.01f;
+                state_proc.red += (state_proc.stats.temp * +w_gain) + (state_proc.stats.tint * t_gain);
+                state_proc.blue += (state_proc.stats.temp * -w_gain) + (state_proc.stats.tint * t_gain);
+                state_proc.blacklevel -= state_proc.stats.blacklevel * 0.001f;
+		state_proc.blacklevel = clamp_float(state_proc.blacklevel, 0.0f, 0.07f);
+		state_proc.red = clamp_float(state_proc.red, 0.5f, 3.0f);
+		state_proc.blue = clamp_float(state_proc.blue, 0.5f, 3.0f);
                 gles2_debayer_set_shading(gles2_debayer, state_proc.red, state_proc.blue, state_proc.blacklevel);
         }
 
@@ -1052,7 +1068,8 @@ update_state(MPPipeline *pipeline, const mp_state_proc *new_state)
                 .focus.manual = state_proc.focus.manual,
 
                 .stats.exposure = state_proc.stats.exposure,
-                .stats.whitebalance = state_proc.stats.whitebalance,
+                .stats.temp = state_proc.stats.temp,
+                .stats.tint = state_proc.stats.tint,
                 .stats.focus = state_proc.stats.focus,
         };
         mp_main_update_state(&new_main);