Brecht Van Lommel
fb03f50e06
Now texture storage of images is defined by the alpha mode of the image. The downside of this is that there can be artifacts near alpha edges where pixels with zero alpha bleed in. It also adds more code complexity since image textures are no longer all stored the same way. This changes allows us to keep using sRGB texture formats, which have edge darkening when stored with premultiplied alpha. Game engines seems to generally do the same thing, and we want to be compatible with them.
73 lines
1.5 KiB
GLSL
73 lines
1.5 KiB
GLSL
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flat in vec4 finalColor;
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#ifndef USE_WIRE
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in vec2 texCoord_interp;
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#endif
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out vec4 fragColor;
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#ifndef USE_WIRE
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uniform sampler2D image;
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uniform bool imagePremultiplied;
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#endif
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uniform int depthMode;
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uniform bool useAlphaTest;
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float linearrgb_to_srgb(float c)
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{
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if (c < 0.0031308) {
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return (c < 0.0) ? 0.0 : c * 12.92;
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}
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else {
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return 1.055 * pow(c, 1.0 / 2.4) - 0.055;
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}
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}
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vec4 texture_read_as_srgb(sampler2D tex, bool premultiplied, vec2 co)
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{
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/* By convention image textures return scene linear colors, but
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* overlays still assume srgb. */
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vec4 color = texture(tex, co);
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/* Unpremultiply if stored multiplied, since straight alpha is expected by shaders. */
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if (premultiplied && !(color.a == 0.0 || color.a == 1.0)) {
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color.rgb = color.rgb / color.a;
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}
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color.r = linearrgb_to_srgb(color.r);
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color.g = linearrgb_to_srgb(color.g);
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color.b = linearrgb_to_srgb(color.b);
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return color;
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}
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void main()
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{
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#ifdef USE_WIRE
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fragColor = finalColor;
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#else
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vec4 tex_col = texture_read_as_srgb(image, imagePremultiplied, texCoord_interp);
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fragColor = finalColor * tex_col;
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if (useAlphaTest) {
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/* Arbitrary discard anything below 5% opacity.
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* Note that this could be exposed to the User. */
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if (tex_col.a < 0.05) {
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discard;
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}
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else {
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fragColor.a = 1.0;
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}
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}
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#endif
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if (depthMode == DEPTH_BACK) {
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gl_FragDepth = 0.999999;
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}
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else if (depthMode == DEPTH_FRONT) {
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gl_FragDepth = 0.000001;
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}
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else if (depthMode == DEPTH_UNCHANGED) {
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gl_FragDepth = gl_FragCoord.z;
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}
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}
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