vulkan: rewrite shaders in terms of eotf and oetf

src/gfx_apis/vulkan/shaders/frag_spec_const.glsl

@@ -3,6 +3,7 @@
 
 layout(constant_id = 0) const bool src_has_alpha = false;
 layout(constant_id = 1) const bool has_alpha_multiplier = false;
-layout(constant_id = 2) const bool color_management = false;
+layout(constant_id = 2) const uint eotf = 0;
+layout(constant_id = 3) const uint oetf = 0;
 
 #endif

src/gfx_apis/vulkan/shaders/out.frag

@@ -10,8 +10,11 @@ layout(location = 0) out vec4 out_color;
 
 void main() {
 	vec4 c = texelFetch(in_color, ivec2(gl_FragCoord.xy), 0);
-	c.rgb /= mix(c.a, 1.0, c.a == 0.0);
-	c.rgb = oetf_srgb(c.rgb);
-	c.rgb *= c.a;
+	if (eotf != oetf) {
+		c.rgb /= mix(c.a, 1.0, c.a == 0.0);
+		c.rgb = apply_eotf(c.rgb);
+		c.rgb = apply_oetf(c.rgb);
+		c.rgb *= c.a;
+	}
 	out_color = c;
 }

src/gfx_apis/vulkan/shaders/tex.frag

@@ -10,11 +10,12 @@ layout(location = 0) out vec4 out_color;
 
 void main() {
 	vec4 c = textureLod(tex, tex_pos, 0);
-	if (color_management) {
+	if (eotf != oetf) {
 		if (src_has_alpha) {
 			c.rgb /= mix(c.a, 1.0, c.a == 0.0);
 		}
-		c.rgb = eotf_srgb(c.rgb);
+		c.rgb = apply_eotf(c.rgb);
+		c.rgb = apply_oetf(c.rgb);
 		if (src_has_alpha) {
 			c.rgb *= c.a;
 		}

src/gfx_apis/vulkan/shaders/transfer_functions.glsl

@@ -1,6 +1,11 @@
 #ifndef TRANSFER_FUNCTIONS_GLSL
 #define TRANSFER_FUNCTIONS_GLSL
 
+#include "frag_spec_const.glsl"
+
+#define SRGB 0
+#define LINEAR 1
+
 vec3 eotf_srgb(vec3 c) {
     return mix(
         c * vec3(1.0 / 12.92),
@@ -18,4 +23,20 @@ vec3 oetf_srgb(vec3 c) {
     );
 }
 
+vec3 apply_eotf(vec3 c) {
+    switch (eotf) {
+        case SRGB: return eotf_srgb(c);
+        case LINEAR: return c;
+        default: return c;
+    }
+}
+
+vec3 apply_oetf(vec3 c) {
+    switch (oetf) {
+        case SRGB: return oetf_srgb(c);
+        case LINEAR: return c;
+        default: return c;
+    }
+}
+
 #endif