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authorEmmanuel Gil Peyrot <emmanuel.peyrot@collabora.com>2015-12-21 21:25:33 +0000
committerToma┼ż Vajngerl <tomaz.vajngerl@collabora.com>2016-01-05 15:05:48 +0100
commit1d411cad5a7d78ead8cffb5da522f1e0fba31187 (patch)
treec0f3134cef987e1e8940ea9db45266f651f683d5 /slideshow/opengl
parent22480b20130d10f4691cdf0a658040be7f36e47b (diff)
slideshow: Improve the Ripple transition to match PowerPoint better
Change-Id: I0b8a78fc6bce5cb737cc7070b1b69184c5f6991c
Diffstat (limited to 'slideshow/opengl')
-rw-r--r--slideshow/opengl/rippleFragmentShader.glsl44
1 files changed, 33 insertions, 11 deletions
diff --git a/slideshow/opengl/rippleFragmentShader.glsl b/slideshow/opengl/rippleFragmentShader.glsl
index ac6b8ac37099..ec641d67a571 100644
--- a/slideshow/opengl/rippleFragmentShader.glsl
+++ b/slideshow/opengl/rippleFragmentShader.glsl
@@ -15,21 +15,43 @@ uniform sampler2D leavingSlideTexture;
uniform sampler2D enteringSlideTexture;
uniform float time;
uniform vec2 center;
+uniform float slideRatio;
+
varying vec2 v_texturePosition;
+// This function returns the distance between two points, taking into account the slide ratio.
+float betterDistance(vec2 p1, vec2 p2)
+{
+ p1.x *= slideRatio;
+ p2.x *= slideRatio;
+ return distance(p1, p2);
+}
+
void main()
{
- float d = length(v_texturePosition - center);
- float w = 0;
- w = max(w, length(center - vec2(0, 0)));
- w = max(w, length(center - vec2(1, 0)));
- w = max(w, length(center - vec2(1, 1)));
- w = max(w, length(center - vec2(0, 1)));
- float v = 0.2;
- float smoothtime = smoothstep(0, 1, time);
- float a = smoothstep(smoothtime*w-v, smoothtime*w+v, d);
- a += (0.5 - abs(a-0.5))*sin(d*M_PI*30);
- gl_FragColor = mix(texture2D(enteringSlideTexture, v_texturePosition), texture2D(leavingSlideTexture, v_texturePosition), a);
+ const float w = 0.5;
+ const float v = 0.1;
+
+ // Distance from this fragment to the center, in slide coordinates.
+ float dist = betterDistance(center, v_texturePosition);
+
+ // We want the ripple to span all of the slide at the end of the transition.
+ float t = time * (sqrt(2.0) * (slideRatio < 1.0 ? 1.0 / slideRatio : slideRatio));
+
+ // Interpolate the distance to the center in fonction of the time.
+ float mixed = smoothstep(t*w-v, t*w+v, dist);
+
+ // Get the displacement offset from the current pixel, for fragments that have been touched by the ripple already.
+ vec2 offset = (v_texturePosition - center) * (sin(dist * 64.0 - time * 16.0) + 0.5) / 32.0;
+ vec2 wavyTexCoord = mix(v_texturePosition + offset, v_texturePosition, time);
+
+ // Get the final position we will sample from.
+ vec2 pos = mix(wavyTexCoord, v_texturePosition, mixed);
+
+ // Sample from the textures and mix that together.
+ vec4 leaving = texture2D(leavingSlideTexture, pos);
+ vec4 entering = texture2D(enteringSlideTexture, pos);
+ gl_FragColor = mix(entering, leaving, mixed);
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */