LibAccelGfx: Add cache for programs

Having programs cache shared between painters would allow us to create
more than one painter without worrying about shaders recompilation.

Userland/Libraries/LibAccelGfx/Painter.cpp

@@ -144,10 +144,10 @@ OwnPtr<Painter> Painter::create()
 
 Painter::Painter(Context& context)
     : m_context(context)
-    , m_rectangle_program(Program::create(vertex_shader_source, solid_color_fragment_shader_source))
-    , m_rounded_rectangle_program(Program::create(vertex_shader_source, rect_with_rounded_corners_fragment_shader_source))
-    , m_blit_program(Program::create(blit_vertex_shader_source, blit_fragment_shader_source))
-    , m_linear_gradient_program(Program::create(linear_gradient_vertex_shader_source, linear_gradient_fragment_shader_source))
+    , m_rectangle_program(Program::create(Program::Name::RectangleProgram, vertex_shader_source, solid_color_fragment_shader_source))
+    , m_rounded_rectangle_program(Program::create(Program::Name::RoundedRectangleProgram, vertex_shader_source, rect_with_rounded_corners_fragment_shader_source))
+    , m_blit_program(Program::create(Program::Name::BlitProgram, blit_vertex_shader_source, blit_fragment_shader_source))
+    , m_linear_gradient_program(Program::create(Program::Name::LinearGradientProgram, linear_gradient_vertex_shader_source, linear_gradient_fragment_shader_source))
     , m_glyphs_texture(GL::create_texture())
 {
     m_state_stack.empend(State());

Userland/Libraries/LibAccelGfx/Program.cpp

@@ -11,12 +11,19 @@
 
 namespace AccelGfx {
 
-Program Program::create(char const* vertex_shader_source, char const* fragment_shader_source)
+Optional<GL::Program> programs_cache[to_underlying(Program::Name::ProgramCount)];
+
+Program Program::create(Name name, char const* vertex_shader_source, char const* fragment_shader_source)
 {
+    if (programs_cache[to_underlying(name)].has_value()) {
+        return Program { *programs_cache[to_underlying(name)] };
+    }
+
     auto vertex_shader = GL::create_shader(GL::ShaderType::Vertex, vertex_shader_source);
     auto fragment_shader = GL::create_shader(GL::ShaderType::Fragment, fragment_shader_source);
 
     auto program = GL::create_program(vertex_shader, fragment_shader);
+    programs_cache[to_underlying(name)] = program;
 
     return Program { program };
 }
@@ -36,9 +43,4 @@ GL::Uniform Program::get_uniform_location(char const* name)
     return GL::get_uniform_location(m_program, name);
 }
 
-Program::~Program()
-{
-    GL::delete_program(m_program);
-}
-
 }

Userland/Libraries/LibAccelGfx/Program.h

@@ -15,14 +15,20 @@ class Program {
     AK_MAKE_NONCOPYABLE(Program);
 
 public:
-    static Program create(char const* vertex_shader_source, char const* fragment_shader_source);
+    enum class Name {
+        RectangleProgram,
+        RoundedRectangleProgram,
+        BlitProgram,
+        LinearGradientProgram,
+        ProgramCount,
+    };
+
+    static Program create(Name name, char const* vertex_shader_source, char const* fragment_shader_source);
 
     void use();
     GL::VertexAttribute get_attribute_location(char const* name);
     GL::Uniform get_uniform_location(char const* name);
 
-    ~Program();
-
 private:
     Program(GL::Program program)
         : m_program(program)