Port over Bitmap 'radial_blur' from old SFML codebase

This implementation is also heaps better than the old
one as it doesn't use a (differently sized) aux texture,
meaning the Bitmap discards its old texture and aquires
one of same size, making reuse through the TexPool a
lot more likely. It also saves on the aux texture blits
and binding switches.

As the setup / resource acquisition far outweighs the
actual rendering cost, operation time is relatively
constant no matter how many divisions are used.

src/shader.cpp

@@ -40,6 +40,7 @@
 #include "../simple.vert.xxd"
 #include "../simpleColor.vert.xxd"
 #include "../sprite.vert.xxd"
+#include "../simpleMatrix.vert.xxd"
 
 
 #define INIT_SHADER(vert, frag) \
@@ -226,6 +227,21 @@ void SimpleSpriteShader::setSpriteMat(const float value[16])
 }
 
 
+SimpleMatrixShader::SimpleMatrixShader()
+{
+	INIT_SHADER(simpleMatrix, simpleAlpha);
+
+	ShaderBase::init();
+
+	GET_U(matrix);
+}
+
+void SimpleMatrixShader::setMatrix(const float value[16])
+{
+	glUniformMatrix4fv(u_matrix, 1, GL_FALSE, value);
+}
+
+
 TransShader::TransShader()
 {
 	INIT_SHADER(simple, trans);