Fixed KRDatablock::Append where the data was not expanded correctly to concatenate a std::String. Converted sprite shader. Adjusted Spirv compile logging.

standard_assets/shaders/sprite.frag

@@ -0,0 +1,45 @@
+//  Copyright 2020 Kearwood Gilbert. All rights reserved.
+//
+//  Redistribution and use in source and binary forms, with or without modification, are
+//  permitted provided that the following conditions are met:
+//
+//  1. Redistributions of source code must retain the above copyright notice, this list of
+//  conditions and the following disclaimer.
+//
+//  2. Redistributions in binary form must reproduce the above copyright notice, this list
+//  of conditions and the following disclaimer in the documentation and/or other materials
+//  provided with the distribution.
+//
+//  THIS SOFTWARE IS PROVIDED BY KEARWOOD GILBERT ''AS IS'' AND ANY EXPRESS OR IMPLIED
+//  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+//  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KEARWOOD GILBERT OR
+//  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+//  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+//  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+//  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+//  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+//  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+//  The views and conclusions contained in the software and documentation are those of the
+//  authors and should not be interpreted as representing official policies, either expressed
+//  or implied, of Kearwood Gilbert.
+//
+
+#version 400
+#extension GL_ARB_separate_shader_objects : enable
+#extension GL_ARB_shading_language_420pack : enable
+
+layout (binding = 0) uniform MaterialObject
+{
+    float alpha;
+} material;
+layout (binding = 1) uniform sampler2D diffuseTexture;
+
+layout (location = 0) in vec2 textureCoordinate;
+layout (location = 0) out vec4 colorOut;
+
+in mediump vec2 texCoord;
+
+void main() {
+    colorOut = vec4(vec3(texture(diffuseTexture, texCoord)), 1.0) * material.alpha;
+}