Ensure aggressive dead-code stripping doesn't break tests

util/test/demos/gl/gl_buffer_truncation.cpp

@@ -50,6 +50,9 @@ void main()
   const std::string pixel = R"EOSHADER(
 #version 460 core
 
+layout(location = 0) in vec4 OUTPOSITION;
+layout(location = 1) in vec4 OUTCOLOR;
+
 layout(location = 0, index = 0) out vec4 Color;
 
 layout(binding = 0, std140) uniform constsbuf
@@ -60,7 +63,7 @@ layout(binding = 0, std140) uniform constsbuf
 
 void main()
 {
-	Color = outcol;
+	Color = outcol + 1e-6f * OUTPOSITION + 1e-6f * OUTCOLOR;
 }
 
 )EOSHADER";

util/test/demos/gl/gl_cbuffer_zoo.cpp

@@ -56,7 +56,7 @@ void main()
 	vertOut.pos = vec4(Position.xyz, 1);
 	gl_Position = vertOut.pos;
 	vertOut.col = Color;
-	vertOut.uv = vec4(UV.xy, 0, 1);
+	vertOut.uv = vec4(UV.xy, 1e-12f, 1);
 }
 
 )EOSHADER";
@@ -404,14 +404,12 @@ void main()
 
     while(Running())
     {
-      glBindFramebuffer(GL_FRAMEBUFFER, 0);
+      glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+      glBindVertexArray(vao);
 
       float col[] = {0.2f, 0.2f, 0.2f, 1.0f};
       glClearBufferfv(GL_COLOR, 0, col);
 
-      glBindFramebuffer(GL_FRAMEBUFFER, fbo);
-      glBindVertexArray(vao);
-
       glBindBufferRange(GL_UNIFORM_BUFFER, 0, cb, bindOffset * sizeof(Vec4f), 1024 * sizeof(Vec4f));
 
       glUseProgram(program);