More efficient stack management

[libs/gl.git] / source / renderer.h

diff --git a/source/renderer.h b/source/renderer.h
index 866881c7b66aeebb8b913c43af4ee14b357c1885..6115a7feeae33deadf6bb327f2d83703cd6f2d87 100644 (file)
--- a/source/renderer.h
+++ b/source/renderer.h
@@ -24,7 +24,14 @@ particular, Objects and Scenes) can by rendered without a Renderer, using one
 will often be more efficient.  This is especially true for ObjectInstances.
 
 The Renderer works by deferring GL state changes until something is actually
-being drawn.  This avoids many unnecessary GL calls. */
+being drawn.  This avoids many unnecessary GL calls if consecutive renderables
+use the same resources.
+
+A state stack is provided to help with state scoping.  Typically a Renderable
+will push the current state on entry, set whatever state it requires, render
+itself, and pop the state when it's done.  An RAII helper class is provided for
+the push/pop operation.
+*/
 class Renderer
 {
 public:
@@ -45,7 +52,7 @@ private:
                const Texturing *texturing;
                const Material *material;
                const Program *shprog;
-               std::vector<const ProgramData *> shdata;
+               unsigned shdata_count;
                const WindingTest *winding_test;
 
                State();
@@ -65,8 +72,10 @@ private:
        MtxStack mtx_stack;
        bool mtx_changed;
        const Camera *camera;
-       std::list<State> state_stack;
+       std::vector<State> state_stack;
        State *state;
+       std::vector<const ProgramData *> shdata_stack;
+       bool shdata_changed;
        const VertexArray *vertex_array;
        bool vertex_array_changed;
        const Buffer *element_buffer;
@@ -82,16 +91,30 @@ public:
        void set_texture(const Texture *);
        void set_texturing(const Texturing *);
        void set_material(const Material *);
-       void set_shader(const Program *, const ProgramData *);
-       void add_shader_data(const ProgramData *);
+
+       /** Sets the shader program to use.  An initial set of data can be set as
+       well, with the same semantics as add_shader_data. */
+       void set_shader_program(const Program *prog, const ProgramData *data = 0);
+
+       /** Adds another set of data to be use with shader programs.  The data is
+       independent of any shader program changes and remains in effect until the
+       Renderer state is popped. */
+       void add_shader_data(const ProgramData &data);
+
        void set_vertex_array(const VertexArray *);
        void set_element_buffer(const Buffer *);
        void set_winding_test(const WindingTest *);
 
+       /** Saves the current state so it can be restored later. */
        void push_state();
+
+       /** Restores a previously saved state.  Must be matched with an earlier
+       push_state call. */
        void pop_state();
 
-       /** Prepares for temporarily bypassing the Renderer. */
+       /** Prepares for temporarily bypassing the Renderer by synchronizing the
+       current state with GL.  No additional call is necessary to resume using the
+       Renderer. */
        void escape();
 
        void draw(const Batch &);