generalization of deferred commands and any_gl rendering where appropriate

src/rendering/twn_draw.c

@@ -4,6 +4,7 @@
 #include "twn_camera_c.h"
 #include "twn_types.h"
 #include "twn_vec.h"
+#include "twn_deferred_commands.h"
 
 #include <SDL2/SDL.h>
 #include <stb_ds.h>
@@ -18,6 +19,8 @@
 #include <tgmath.h>
 
 
+DeferredCommand *deferred_commands;
+
 /* TODO: have a default initialized one */
 Matrix4 camera_projection_matrix;
 Matrix4 camera_look_at_matrix;
@@ -401,3 +404,125 @@ DrawCameraFromPrincipalAxesResult draw_camera_from_principal_axes(Vec3 position,
         .up = camera.up,
     };
 }
+
+
+void set_depth_range(double low, double high) {
+    DeferredCommand const command = {
+        .type = DEFERRED_COMMAND_TYPE_DEPTH_RANGE,
+        .depth_range = {
+            .low = low,
+            .high = high
+        }
+    };
+
+    arrpush(deferred_commands, command);
+}
+
+
+void clear_draw_buffer(void) {
+    /* TODO: we can optimize a rectangle drawn over whole window to a clear color call*/
+
+    DeferredCommand command = {
+        .type = DEFERRED_COMMAND_TYPE_CLEAR,
+        .clear = (DeferredCommandClear) {
+            .clear_color = true,
+            .clear_depth = true,
+            .clear_stencil = true,
+            .color = (Color) { 230, 230, 230, 1 }
+        }
+    };
+
+    arrpush(deferred_commands, command);
+}
+
+
+void use_texture_mode(TextureMode mode) {
+    DeferredCommand const command = {
+        .type = DEFERRED_COMMAND_TYPE_USE_TEXTURE_MODE,
+        .use_texture_mode = { mode }
+    };
+
+    arrpush(deferred_commands, command);
+}
+
+
+void use_2d_pipeline(void) {
+    DeferredCommand const command = {
+        .type = DEFERRED_COMMAND_TYPE_USE_PIPIELINE,
+        .use_pipeline = { PIPELINE_2D }
+    };
+
+    arrpush(deferred_commands, command);
+}
+
+
+void use_space_pipeline(void) {
+    DeferredCommand const command = {
+        .type = DEFERRED_COMMAND_TYPE_USE_PIPIELINE,
+        .use_pipeline = { PIPELINE_SPACE }
+    };
+
+    arrpush(deferred_commands, command);
+}
+
+
+void issue_deferred_draw_commands(void) {
+    for (size_t i = 0; i < arrlenu(deferred_commands); ++i) {
+        switch (deferred_commands[i].type) {
+            case DEFERRED_COMMAND_TYPE_DEPTH_RANGE: {
+                finally_set_depth_range(deferred_commands[i].depth_range);
+                break;
+            }
+
+            case DEFERRED_COMMAND_TYPE_CLEAR: {
+                finally_clear_draw_buffer(deferred_commands[i].clear);
+                break;
+            }
+
+            case DEFERRED_COMMAND_TYPE_DRAW: {
+                finally_draw_command(deferred_commands[i].draw);
+                break;
+            }
+
+            case DEFERRED_COMMAND_TYPE_DRAW_SKYBOX: {
+                finally_render_skybox(deferred_commands[i].draw_skybox);
+                break;
+            }
+
+            case DEFERRED_COMMAND_TYPE_USE_PIPIELINE: {
+                switch (deferred_commands[i].use_pipeline.pipeline) {
+                    case PIPELINE_2D:
+                        finally_use_2d_pipeline();
+                        break;
+                    case PIPELINE_SPACE:
+                        finally_use_space_pipeline();
+                        break;
+                    case PIPELINE_NO:
+                    default:
+                        SDL_assert(false);
+                }
+
+                break;
+            }
+
+            case DEFERRED_COMMAND_TYPE_USE_TEXTURE_MODE: {
+                finally_use_texture_mode(deferred_commands[i].use_texture_mode.mode);
+                break;
+            }
+
+            case DEFERRED_COMMAND_TYPE_APPLY_FOG: {
+                finally_apply_fog(deferred_commands[i].apply_fog);
+                break;
+            }
+
+            case DEFERRED_COMMAND_TYPE_POP_FOG: {
+                finally_pop_fog();
+                break;
+            }
+
+            default:
+                SDL_assert(false);
+        }
+    }
+}
+