1 files changed, 68 insertions, 0 deletions
diff --git a/slideshow/opengl/vortexFragmentShader.glsl b/slideshow/opengl/vortexFragmentShader.glsl
new file mode 100644
index 000000000..6bcdfc5da
--- /dev/null
+++ b/slideshow/opengl/vortexFragmentShader.glsl
@@ -0,0 +1,68 @@
+/* -*- 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: */