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change halo-width/blur units

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refs mapbox/mapbox-gl-style-spec#66
This commit is contained in:
Konstantin Käfer
2014-07-14 18:25:07 -07:00
parent 9213f8d8e0
commit 471dafc1d1
1 changed files with 27 additions and 15 deletions
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42
src/renderer/painter_text.cpp
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@@ -89,23 +89,37 @@ void Painter::renderText(TextBucket& bucket, std::shared_ptr<StyleLayer> layer_d
textShader->setMaxFadeZoom(std::floor(highZ * 10));
textShader->setFadeZoom((map.getState().getNormalizedZoom() + bump) * 10);
// This defines the gamma around the SDF cutoff value.
const float sdfGamma = 0.75f / 10.0f;
// Our signed distance fields are scaled so that 1 pixel is scaled to 32 pixels.
// Our cutoff between positive and negative values is hard coded to 64 (== 2 pixels).
// This means that our 6/8 of the value range lies outside the glyph outline.
const float sdfOffset = (256.0f - 64.0f) / 32.0f;
// Currently, all of our fonts are rendered with a font size of 24px.
const float sdfFontSize = 24.0f;
// The default gamma value has to be adjust for the current pixelratio so that we're not drawing
// blurry font on retina screens.
const float gamma = sdfGamma * sdfFontSize / fontSize / map.getState().getPixelRatio();
// We're drawing in the translucent pass which is bottom-to-top, so we need
// to draw the halo first.
if (properties.halo_color[3] > 0.0f) {
// TODO: Get rid of the 2.4 magic value. It is currently 24 / 10, with 24 being the font size
// of the SDF glyphs.
// Our signed distance fields are scaled so that 1 pixel is scaled to 32 pixels.
// Our cutoff between positive and negative values is hard coded to 64 (== 2 pixels).
// This means that our 6/8 of the value range lies outside the glyph outline.
const float sdfOffset = (256.0f - 64.0f) / 32.0f;
// Currently, all of our fonts are rendered with a font size of 24px.
const float sdfFontSize = 24.0f;
const float haloWidth = util::clamp((sdfOffset - properties.halo_width / (fontSize / sdfFontSize)) / 8.0f, 0.0f, 1.0f);
textShader->setGamma(properties.halo_blur * 2.4f / fontSize / map.getState().getPixelRatio());
if (properties.halo_blur != 0.0f) {
// We are converting the halo_blur value to current screen pixels.
// Then we're dividing it by two because the gamma value is added/subtracted into both
// directions in the shader, but the halo_blur describes the entire width of the blur.
// Note that this does *not* have to be adjusted for retina screens, because we want the
// same blur width when we explicitly specify one.
textShader->setGamma((properties.halo_blur / (fontSize / sdfFontSize)) / 8.0f / 2.0f);
} else {
textShader->setGamma(sdfGamma);
}
if (properties.opacity < 1.0f) {
Color color = properties.halo_color;
color[0] *= properties.opacity;
@@ -123,9 +137,7 @@ void Painter::renderText(TextBucket& bucket, std::shared_ptr<StyleLayer> layer_d
if (properties.color[3] > 0.0f) {
// Then, we draw the text over the halo
// TODO: Get rid of the 2.4 magic value. It is currently 24 / 10, with 24 being the font size
// of the SDF glyphs.
textShader->setGamma(2.4f / fontSize / map.getState().getPixelRatio());
textShader->setGamma(gamma);
if (properties.opacity < 1.0f) {
Color color = properties.color;
color[0] *= properties.opacity;