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vo_opengl: add oversample scaler

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This is like nearest neighbour, but the edges between pixels are
linearly interpolating if needed, as if they had been (naively)
oversampled.
This commit is contained in:
Niklas Haas 2015-03-15 06:27:11 +01:00
parent 44a78a2be2
commit ac1e31957d
2 changed files with 44 additions and 0 deletions
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6
DOCS/man/vo.rst
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@ -356,6 +356,12 @@ Available video output drivers are:
Sharpening strength. Increasing this makes the image sharper but
adds more ringing and aliasing. Defaults to 0.5.
``oversample``
Minimum distance to an edge before interpolation is used. Setting
this to 0 will always interpolate edges, whereas setting it to 0.5
will never interpolate, thus behaving as if the regular nearest
neighbour algorithm was used. Defaults to 0.0.
``scale-radius=<r>``
Set radius for filters listed below, must be a float number between 1.0
and 16.0. Defaults to be 3.0 if not specified.

38
video/out/gl_video.c
View File

@ -59,6 +59,7 @@ static const char *const fixed_scale_filters[] = {
"bicubic_fast",
"sharpen3",
"sharpen5",
"oversample",
NULL
};
@ -1178,6 +1179,41 @@ static void pass_sample_sharpen5(struct gl_video *p, struct scaler *scaler)
GLSLF("}\n");
}
static void pass_sample_oversample(struct gl_video *p, struct scaler *scaler,
int w, int h)
{
GLSL(vec4 color;)
GLSLF("{\n");
GLSL(vec2 pt = 1.0 / sample_size;)
GLSL(vec2 pos = sample_pos + vec2(0.5) * pt;) // round to nearest
GLSL(vec2 fcoord = fract(pos * sample_size - vec2(0.5));)
// We only need to sample from the four corner pixels since we're using
// nearest neighbour and can compute the exact transition point
GLSL(vec2 baseNW = pos - fcoord * pt;)
GLSL(vec2 baseNE = baseNW + vec2(pt.x, 0.0);)
GLSL(vec2 baseSW = baseNW + vec2(0.0, pt.y);)
GLSL(vec2 baseSE = baseNW + pt;)
// Determine the mixing coefficient vector
gl_sc_uniform_vec2(p->sc, "output_size", (float[2]){w, h});
GLSL(vec2 coeff = vec2((baseSE - pos) * output_size);)
GLSL(coeff = clamp(coeff, 0.0, 1.0);)
if (scaler->params[0] > 0) { // also rules out NAN
GLSLF("coeff = mix(coeff, vec2(0.0), "
"lessThanEqual(coeff, vec2(%f)));\n", scaler->params[0]);
GLSLF("coeff = mix(coeff, vec2(1.0), "
"greaterThanEqual(coeff, vec2(%f)));\n", scaler->params[0]);
}
// Compute the right blend of colors
GLSL(vec4 left = mix(texture(sample_tex, baseSW),
texture(sample_tex, baseNW),
coeff.y);)
GLSL(vec4 right = mix(texture(sample_tex, baseSE),
texture(sample_tex, baseNE),
coeff.y);)
GLSL(color = mix(right, left, coeff.x);)
GLSLF("}\n");
}
// Sample. This samples from the texture ID given by src_tex. It's hardcoded to
// use all variables and values associated with it (which includes textureN,
// texcoordN and texture_sizeN).
@ -1212,6 +1248,8 @@ static void pass_sample(struct gl_video *p, int src_tex,
pass_sample_sharpen3(p, scaler);
} else if (strcmp(scaler->name, "sharpen5") == 0) {
pass_sample_sharpen5(p, scaler);
} else if (strcmp(scaler->name, "oversample") == 0) {
pass_sample_oversample(p, scaler, w, h);
} else if (scaler->kernel && scaler->kernel->polar) {
pass_sample_polar(p, scaler);
} else if (scaler->kernel) {