From 02d1a3c1c3169784c18a6cd874ef94d099d8f444 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Wernst=C3=A5l?= <m4rw3r@gmail.com>
Date: Mon, 23 Jan 2023 14:12:14 +0100
Subject: [PATCH] feat(srgb): swap textures and framebuffers to SRGB

---
 kitty/gl.c      | 2 +-
 kitty/glfw.c    | 3 +++
 kitty/shaders.c | 8 ++++----
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/kitty/gl.c b/kitty/gl.c
index 21435bd09..2776c121c 100644
--- a/kitty/gl.c
+++ b/kitty/gl.c
@@ -71,7 +71,7 @@ update_surface_size(int w, int h, GLuint offscreen_texture_id) {
     glViewport(0, 0, w, h);
     if (offscreen_texture_id) {
         glBindTexture(GL_TEXTURE_2D, offscreen_texture_id);
-        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB_ALPHA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
     }
 }
 
diff --git a/kitty/glfw.c b/kitty/glfw.c
index 3c490c2b1..5cd6f85b9 100644
--- a/kitty/glfw.c
+++ b/kitty/glfw.c
@@ -11,6 +11,7 @@
 #include "charsets.h"
 #include <structmember.h>
 #include "glfw-wrapper.h"
+#include "gl.h"
 #ifndef __APPLE__
 #include "freetype_render_ui_text.h"
 #endif
@@ -870,6 +871,8 @@ create_os_window(PyObject UNUSED *self, PyObject *args, PyObject *kw) {
     if (is_first_window) {
         gl_init();
     }
+    // Will make the GPU automatically apply SRGB gamma curve on the resulting framebuffer
+    glEnable(GL_FRAMEBUFFER_SRGB);
     bool is_semi_transparent = glfwGetWindowAttrib(glfw_window, GLFW_TRANSPARENT_FRAMEBUFFER);
     // blank the window once so that there is no initial flash of color
     // changing, in case the background color is not black
diff --git a/kitty/shaders.c b/kitty/shaders.c
index 21a391bb1..0158333ef 100644
--- a/kitty/shaders.c
+++ b/kitty/shaders.c
@@ -102,7 +102,7 @@ realloc_sprite_texture(FONTS_DATA_HANDLE fg) {
     znum = z + 1;
     SpriteMap *sprite_map = (SpriteMap*)fg->sprite_map;
     width = xnum * sprite_map->cell_width; height = ynum * sprite_map->cell_height;
-    glTexStorage3D(GL_TEXTURE_2D_ARRAY, 1, GL_RGBA8, width, height, znum);
+    glTexStorage3D(GL_TEXTURE_2D_ARRAY, 1, GL_SRGB8_ALPHA8, width, height, znum);
     if (sprite_map->texture_id) {
         // need to re-alloc
         src_ynum = MAX(1, sprite_map->last_ynum);
@@ -159,7 +159,7 @@ send_image_to_gpu(GLuint *tex_id, const void* data, GLsizei width, GLsizei heigh
     }
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, r);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, r);
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, is_opaque ? GL_RGB : GL_RGBA, GL_UNSIGNED_BYTE, data);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB_ALPHA, width, height, 0, is_opaque ? GL_RGB : GL_RGBA, GL_UNSIGNED_BYTE, data);
 }
 
 // }}}
@@ -612,7 +612,7 @@ render_a_bar(OSWindow *os_window, Screen *screen, const CellRenderData *crd, Win
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, bar_width, bar_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, bar->buf);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB_ALPHA, bar_width, bar_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, bar->buf);
     set_cell_uniforms(1.f, false);
     bind_program(GRAPHICS_PROGRAM);
     send_graphics_data_to_gpu(1, os_window->gvao_idx, &data);
@@ -793,7 +793,7 @@ draw_cells_interleaved_premult(ssize_t vao_idx, ssize_t gvao_idx, Screen *screen
         glGenFramebuffers(1, &os_window->offscreen_framebuffer);
         glGenTextures(1, &os_window->offscreen_texture_id);
         glBindTexture(GL_TEXTURE_2D, os_window->offscreen_texture_id);
-        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, os_window->viewport_width, os_window->viewport_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB_ALPHA, os_window->viewport_width, os_window->viewport_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);