began external shader files that can be compiled into the program

Helps write shaders rather than embedding them into the C++ code.

app/shaders/CMakeLists.txt

@@ -0,0 +1,21 @@
+# Olive - Non-Linear Video Editor
+# Copyright (C) 2019 Olive Team
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+set(OLIVE_RESOURCES
+  ${OLIVE_RESOURCES}
+  shaders/shaders.qrc
+  PARENT_SCOPE
+)

app/shaders/shaders.qrc

@@ -0,0 +1,6 @@
+<RCC>
+    <qresource prefix="/shaders">
+        <file>videoinput.frag</file>
+        <file>videoinput.vert</file>
+    </qresource>
+</RCC>

app/shaders/videoinput.frag

@@ -0,0 +1,8 @@
+#version 110
+
+varying vec2 ove_texcoord;
+uniform sampler2D footage_in;
+
+void main(void) {
+  gl_FragColor = texture2D(footage_in, ove_texcoord);
+}

app/shaders/videoinput.vert

@@ -0,0 +1,37 @@
+#version 110
+
+uniform mat4 matrix_in;
+
+attribute vec4 a_position;
+attribute vec2 a_texcoord;
+
+varying vec2 ove_texcoord;
+
+uniform vec2 footage_in_resolution;
+uniform vec2 ove_resolution;
+
+mat4 scale_mat4(vec3 scale) {
+  return mat4(
+    scale.x, 0.0, 0.0, 0.0,
+    0.0, scale.y, 0.0, 0.0,
+    0.0, 0.0, scale.z, 0.0,
+    0.0, 0.0, 0.0, 1.0
+  );
+}
+
+void main() {
+  // Create identity matrix
+  mat4 transform = mat4(1.0);
+
+  // Scale to square
+  transform *= scale_mat4(vec3(1.0/ove_resolution, 1.0));
+
+  // Multiply by received matrix
+  transform *= matrix_in;
+
+  // Scale back out to footage size
+  transform *= scale_mat4(vec3(footage_in_resolution, 1.0));
+
+  gl_Position = transform * a_position;
+  ove_texcoord = a_texcoord;
+}