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authorSimon Ser <contact@emersion.fr>2023-10-17 12:21:08 +0200
committerSimon Ser <contact@emersion.fr>2023-10-17 17:28:56 +0200
commit5adf325333602d5b1e7ccdeb122633bbc8040ace (patch)
treeafd116e7131bd9827e8b05eb9f2ff1cdd04f8f18 /render/vulkan/shaders
parentb560f362073f7981c15f820488441e50f697d306 (diff)
render/vulkan: undo alpha premult before sRGB encoding/decoding
sRGB encoding/decoding needs to happen with straight alpha, not pre-multiplied alpha.
Diffstat (limited to 'render/vulkan/shaders')
-rw-r--r--render/vulkan/shaders/output.frag24
-rw-r--r--render/vulkan/shaders/texture.frag24
2 files changed, 32 insertions, 16 deletions
diff --git a/render/vulkan/shaders/output.frag b/render/vulkan/shaders/output.frag
index 28a8cdc5..263f3e19 100644
--- a/render/vulkan/shaders/output.frag
+++ b/render/vulkan/shaders/output.frag
@@ -5,17 +5,25 @@ layout (input_attachment_index = 0, binding = 0) uniform subpassInput in_color;
layout(location = 0) in vec2 uv;
layout(location = 0) out vec4 out_color;
-float linear_to_srgb(float x) {
+float linear_channel_to_srgb(float x) {
return max(min(x * 12.92, 0.04045), 1.055 * pow(x, 1. / 2.4) - 0.055);
}
-void main() {
- vec4 val = subpassLoad(in_color).rgba;
- out_color = vec4(
- linear_to_srgb(val.r),
- linear_to_srgb(val.g),
- linear_to_srgb(val.b),
- val.a
+vec4 linear_color_to_srgb(vec4 color) {
+ if (color.a == 0) {
+ return vec4(0);
+ }
+ color.rgb /= color.a;
+ color.rgb = vec3(
+ linear_channel_to_srgb(color.r),
+ linear_channel_to_srgb(color.g),
+ linear_channel_to_srgb(color.b)
);
+ color.rgb *= color.a;
+ return color;
}
+void main() {
+ vec4 val = subpassLoad(in_color).rgba;
+ out_color = linear_color_to_srgb(val);
+}
diff --git a/render/vulkan/shaders/texture.frag b/render/vulkan/shaders/texture.frag
index 8b5a0c8d..eab2c2d1 100644
--- a/render/vulkan/shaders/texture.frag
+++ b/render/vulkan/shaders/texture.frag
@@ -15,23 +15,31 @@ layout (constant_id = 0) const int TEXTURE_TRANSFORM = 0;
#define TEXTURE_TRANSFORM_IDENTITY 0
#define TEXTURE_TRANSFORM_SRGB 1
-float srgb_to_linear(float x) {
+float srgb_channel_to_linear(float x) {
return max(x / 12.92, pow((x + 0.055) / 1.055, 2.4));
}
+vec4 srgb_color_to_linear(vec4 color) {
+ if (color.a == 0) {
+ return vec4(0);
+ }
+ color.rgb /= color.a;
+ color.rgb = vec3(
+ srgb_channel_to_linear(color.r),
+ srgb_channel_to_linear(color.g),
+ srgb_channel_to_linear(color.b)
+ );
+ color.rgb *= color.a;
+ return color;
+}
+
void main() {
vec4 val = textureLod(tex, uv, 0);
if (TEXTURE_TRANSFORM == TEXTURE_TRANSFORM_SRGB) {
- out_color = vec4(
- srgb_to_linear(val.r),
- srgb_to_linear(val.g),
- srgb_to_linear(val.b),
- val.a
- );
+ out_color = srgb_color_to_linear(val);
} else { // TEXTURE_TRANSFORM_IDENTITY
out_color = val;
}
out_color *= data.alpha;
}
-