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/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#version 150
uniform sampler2D slideTexture;
uniform sampler2D leavingShadowTexture;
uniform sampler2D enteringShadowTexture;
in vec2 v_texturePosition;
in vec3 v_normal;
in vec4 shadowCoordinate;
void main() {
const vec2 samplingPoints[9] = vec2[](
vec2(0, 0),
vec2(-1, -1),
vec2(-1, 0),
vec2(-1, 1),
vec2(0, 1),
vec2(1, 1),
vec2(1, 0),
vec2(1, -1),
vec2(0, -1)
);
// Compute the shadow...
float visibility = 1.0;
const float epsilon = 0.0001;
// for the leaving slide,
{
float depthShadow = texture(leavingShadowTexture, shadowCoordinate.xy).r;
float shadowRadius = (1.0 / (shadowCoordinate.z - depthShadow)) * 1000.0;
for (int i = 0; i < 9; ++i) {
vec2 coordinate = shadowCoordinate.xy + samplingPoints[i] / shadowRadius;
if (texture(leavingShadowTexture, coordinate).r < shadowCoordinate.z - epsilon) {
visibility -= 0.05;
}
}
}
// and for entering slide.
{
float depthShadow = texture(enteringShadowTexture, shadowCoordinate.xy).r;
float shadowRadius = (1.0 / (shadowCoordinate.z - depthShadow)) * 1000.0;
for (int i = 0; i < 9; ++i) {
vec2 coordinate = shadowCoordinate.xy + samplingPoints[i] / shadowRadius;
if (texture(enteringShadowTexture, coordinate).r < shadowCoordinate.z - epsilon) {
visibility -= 0.05;
}
}
}
vec3 lightVector = vec3(0.0, 0.0, 1.0);
float light = max(dot(lightVector, v_normal), 0.0);
vec4 fragment = texture(slideTexture, v_texturePosition);
vec4 black = vec4(0.0, 0.0, 0.0, fragment.a);
gl_FragColor = mix(black, fragment, visibility * light);
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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