image-source: Support linear SRGB

Both image and color sources have been updated.

Also added alpha support to the color source. Useful for users, and
serves as an easy alpha blending test case.

plugins/image-source/color-source.c

@@ -1,7 +1,8 @@
 #include <obs-module.h>
 
 struct color_source {
-	uint32_t color;
+	struct vec4 color;
+	struct vec4 color_srgb;
 
 	uint32_t width;
 	uint32_t height;
@@ -22,7 +23,8 @@ static void color_source_update(void *data, obs_data_t *settings)
 	uint32_t width = (uint32_t)obs_data_get_int(settings, "width");
 	uint32_t height = (uint32_t)obs_data_get_int(settings, "height");
 
-	context->color = color;
+	vec4_from_rgba(&context->color, color);
+	vec4_from_rgba_srgb(&context->color_srgb, color);
 	context->width = width;
 	context->height = height;
 }
@@ -50,8 +52,8 @@ static obs_properties_t *color_source_properties(void *unused)
 
 	obs_properties_t *props = obs_properties_create();
 
-	obs_properties_add_color(props, "color",
-				 obs_module_text("ColorSource.Color"));
+	obs_properties_add_color_alpha(props, "color",
+				       obs_module_text("ColorSource.Color"));
 
 	obs_properties_add_int(props, "width",
 			       obs_module_text("ColorSource.Width"), 0, 4096,
@@ -64,19 +66,14 @@ static obs_properties_t *color_source_properties(void *unused)
 	return props;
 }
 
-static void color_source_render(void *data, gs_effect_t *effect)
+static void color_source_render_helper(struct color_source *context,
+				       struct vec4 *colorVal)
 {
-	UNUSED_PARAMETER(effect);
-
-	struct color_source *context = data;
-
 	gs_effect_t *solid = obs_get_base_effect(OBS_EFFECT_SOLID);
 	gs_eparam_t *color = gs_effect_get_param_by_name(solid, "color");
 	gs_technique_t *tech = gs_effect_get_technique(solid, "Solid");
 
-	struct vec4 colorVal;
-	vec4_from_rgba(&colorVal, context->color);
-	gs_effect_set_vec4(color, &colorVal);
+	gs_effect_set_vec4(color, colorVal);
 
 	gs_technique_begin(tech);
 	gs_technique_begin_pass(tech, 0);
@@ -87,6 +84,27 @@ static void color_source_render(void *data, gs_effect_t *effect)
 	gs_technique_end(tech);
 }
 
+static void color_source_render(void *data, gs_effect_t *effect)
+{
+	UNUSED_PARAMETER(effect);
+
+	struct color_source *context = data;
+
+	/* need linear path for correct alpha blending */
+	const bool linear_srgb = gs_get_linear_srgb() ||
+				 (context->color.w < 1.0f);
+
+	const bool previous = gs_framebuffer_srgb_enabled();
+	gs_enable_framebuffer_srgb(linear_srgb);
+
+	if (linear_srgb)
+		color_source_render_helper(context, &context->color_srgb);
+	else
+		color_source_render_helper(context, &context->color);
+
+	gs_enable_framebuffer_srgb(previous);
+}
+
 static uint32_t color_source_getwidth(void *data)
 {
 	struct color_source *context = data;

plugins/image-source/image-source.c

@@ -147,10 +147,21 @@ static void image_source_render(void *data, gs_effect_t *effect)
 	if (!context->if2.image.texture)
 		return;
 
-	gs_effect_set_texture(gs_effect_get_param_by_name(effect, "image"),
-			      context->if2.image.texture);
+	const bool linear_srgb = gs_get_linear_srgb();
+
+	const bool previous = gs_framebuffer_srgb_enabled();
+	gs_enable_framebuffer_srgb(linear_srgb);
+
+	gs_eparam_t *const param = gs_effect_get_param_by_name(effect, "image");
+	if (linear_srgb)
+		gs_effect_set_texture_srgb(param, context->if2.image.texture);
+	else
+		gs_effect_set_texture(param, context->if2.image.texture);
+
 	gs_draw_sprite(context->if2.image.texture, 0, context->if2.image.cx,
 		       context->if2.image.cy);
+
+	gs_enable_framebuffer_srgb(previous);
 }
 
 static void image_source_tick(void *data, float seconds)