vo_opengl: add manual sRGB companding to not artifact when dithering

Patch by nand. Modified not to use macros in the GLSL, and also remove
the checks for framebuffer presence. (Disabling ICC if no sRGB
framebuffer is available was probably a bug.)

2 files changed, 11 insertions, 14 deletions

diff --git a/libvo/vo_opengl.c b/libvo/vo_opengl.c
index 261e1b102f..04a3559be5 100644
--- a/libvo/vo_opengl.c
+++ b/libvo/vo_opengl.c
@@ -698,6 +698,7 @@ static void compile_shaders(struct gl_priv *p)
     shader_def_opt(&header_final, "USE_LINEAR_CONV_INV", p->use_lut_3d);
     shader_def_opt(&header_final, "USE_GAMMA_POW", p->use_gamma);
     shader_def_opt(&header_final, "USE_3DLUT", p->use_lut_3d);
+    shader_def_opt(&header_final, "USE_SRGB", p->use_srgb);
     shader_def_opt(&header_final, "USE_DITHER", p->dither_texture != 0);
 
     if (p->use_scale_sep && p->scalers[0].kernel) {
@@ -1122,11 +1123,6 @@ static void do_render(struct gl_priv *p)
     float final_texw = p->image_width * source->tex_w / (float)source->vp_w;
     float final_texh = p->image_height * source->tex_h / (float)source->vp_h;
 
-    bool use_srgb_fb = p->use_srgb && !p->use_lut_3d;
-
-    if (use_srgb_fb)
-        gl->Enable(GL_FRAMEBUFFER_SRGB);
-
     if (p->stereo_mode) {
         int w = p->src_rect.x1 - p->src_rect.x0;
         int imgw = p->image_width;
@@ -1165,9 +1161,6 @@ static void do_render(struct gl_priv *p)
         draw_triangles(p, vb, VERTICES_PER_QUAD);
     }
 
-    if (use_srgb_fb)
-        gl->Disable(GL_FRAMEBUFFER_SRGB);
-
     gl->UseProgram(0);
 
     debug_check_gl(p, "after video rendering");
@@ -1457,8 +1450,7 @@ static void check_gl_features(struct gl_priv *p)
     GL *gl = p->gl;
     bool have_float_tex = gl->mpgl_caps & MPGL_CAP_FLOAT_TEX;
     bool have_fbo = gl->mpgl_caps & MPGL_CAP_FB;
-    bool have_srgb = (gl->mpgl_caps & MPGL_CAP_SRGB_TEX) &&
-                     (gl->mpgl_caps & MPGL_CAP_SRGB_FB);
+    bool have_srgb = gl->mpgl_caps & MPGL_CAP_SRGB_TEX;
 
     char *disabled[10];
     int n_disabled = 0;
@@ -1493,10 +1485,6 @@ static void check_gl_features(struct gl_priv *p)
         p->use_lut_3d = false;
         disabled[n_disabled++] = "color management (FBO)";
     }
-    if (!have_srgb && p->use_lut_3d) {
-        p->use_lut_3d = false;
-        disabled[n_disabled++] = "color management (sRGB)";
-    }
 
     if (!have_fbo) {
         p->use_scale_sep = false;
diff --git a/libvo/vo_opengl_shaders.glsl b/libvo/vo_opengl_shaders.glsl
index 01e1433f7f..32804b99ff 100644
--- a/libvo/vo_opengl_shaders.glsl
+++ b/libvo/vo_opengl_shaders.glsl
@@ -292,6 +292,12 @@ vec4 sample_sharpen5(sampler2D tex, vec2 texsize, vec2 texcoord) {
     return p + t * filter_param1;
 }
 
+vec3 srgb_compand(vec3 v)
+{
+    return mix(1.055 * pow(v, vec3(1.0/2.4)) - vec3(0.055), v * 12.92,
+               lessThanEqual(v, vec3(0.0031308)));
+}
+
 void main() {
 #ifdef USE_PLANAR
     vec3 color = vec3(SAMPLE_L(textures[0], textures_size[0], texcoord).r,
@@ -325,6 +331,9 @@ void main() {
 #ifdef USE_3DLUT
     color = texture3D(lut_3d, color).rgb;
 #endif
+#ifdef USE_SRGB
+    color.rgb = srgb_compand(color.rgb);
+#endif
 #ifdef USE_DITHER
     float dither_value = texture(dither, gl_FragCoord.xy / dither_size).r;
     color = floor(color * dither_multiply + dither_value ) / dither_quantization;