GPUFramebuffer: Refactor (Part 2)

This refactor modernise the use of framebuffers.
It also touches a lot of files so breaking down changes we have:
 - GPUTexture: Allow textures to be attached to more than one GPUFrameBuffer.
   This allows to create and configure more FBO without the need to attach
   and detach texture at drawing time.
 - GPUFrameBuffer: The wrapper starts to mimic opengl a bit closer. This
   allows to configure the framebuffer inside a context other than the one
   that will be rendering the framebuffer. We do the actual configuration
   when binding the FBO. We also Keep track of config validity and save
   drawbuffers state in the FBO. We remove the different bind/unbind
   functions. These make little sense now that we have separate contexts.
 - DRWFrameBuffer: We replace DRW_framebuffer functions by GPU_framebuffer
   ones to avoid another layer of abstraction. We move the DRW convenience
   functions to GPUFramebuffer instead and even add new ones. The MACRO
   GPU_framebuffer_ensure_config is pretty much all you need to create and
   config a GPUFramebuffer.
 - DRWTexture: Due to the removal of DRWFrameBuffer, we needed to create
   functions to create textures for thoses framebuffers. Pool textures are
   now using default texture parameters for the texture type asked.
 - DRWManager: Make sure no framebuffer object is bound when doing cache
   filling.
 - GPUViewport: Add new color_only_fb and depth_only_fb along with FB API
   usage update. This let draw engines render to color/depth only target
   and without the need to attach/detach textures.
 - WM_window: Assert when a framebuffer is bound when changing context.
   This balance the fact we are not track ogl context inside GPUFramebuffer.
 - Eevee, Clay, Mode engines: Update to new API. This comes with a lot of
   code simplification.

This also come with some cleanups in some engine codes.

1 files changed, 33 insertions, 28 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_engine.c b/source/blender/draw/engines/eevee/eevee_engine.c
index 6cfecd0a226..276f23c7cf7 100644
--- a/source/blender/draw/engines/eevee/eevee_engine.c
+++ b/source/blender/draw/engines/eevee/eevee_engine.c
@@ -55,6 +55,7 @@ static void eevee_engine_init(void *ved)
 	EEVEE_FramebufferList *fbl = vedata->fbl;
 	EEVEE_StorageList *stl = ((EEVEE_Data *)vedata)->stl;
 	EEVEE_ViewLayerData *sldata = EEVEE_view_layer_data_ensure();
+	DefaultTextureList *dtxl = DRW_viewport_texture_list_get();
 
 	const DRWContextState *draw_ctx = DRW_context_state_get();
 	View3D *v3d = draw_ctx->v3d;
@@ -68,12 +69,22 @@ static void eevee_engine_init(void *ved)
 	stl->g_data->background_alpha = DRW_state_draw_background() ? 1.0f : 0.0f;
 	stl->g_data->valid_double_buffer = (txl->color_double_buffer != NULL);
 
-	DRWFboTexture tex = {&txl->color, DRW_TEX_RGBA_16, DRW_TEX_FILTER | DRW_TEX_MIPMAP};
+	/* Main Buffer */
+	DRW_texture_ensure_fullscreen_2D(&txl->color, DRW_TEX_RGBA_16, DRW_TEX_FILTER | DRW_TEX_MIPMAP);
+
+	GPU_framebuffer_ensure_config(&fbl->main_fb, {
+		GPU_ATTACHMENT_TEXTURE(dtxl->depth),
+		GPU_ATTACHMENT_TEXTURE(txl->color),
+		GPU_ATTACHMENT_LEAVE,
+		GPU_ATTACHMENT_LEAVE,
+		GPU_ATTACHMENT_LEAVE,
+		GPU_ATTACHMENT_LEAVE
+	});
 
-	const float *viewport_size = DRW_viewport_size_get();
-	DRW_framebuffer_init(&fbl->main, &draw_engine_eevee_type,
-	                    (int)viewport_size[0], (int)viewport_size[1],
-	                    &tex, 1);
+	GPU_framebuffer_ensure_config(&fbl->main_color_fb, {
+		GPU_ATTACHMENT_NONE,
+		GPU_ATTACHMENT_TEXTURE(txl->color)
+	});
 
 	if (sldata->common_ubo == NULL) {
 		sldata->common_ubo = DRW_uniformbuffer_create(sizeof(sldata->common_data), &sldata->common_data);
@@ -170,6 +181,7 @@ static void eevee_draw_background(void *vedata)
 	EEVEE_TextureList *txl = ((EEVEE_Data *)vedata)->txl;
 	EEVEE_StorageList *stl = ((EEVEE_Data *)vedata)->stl;
 	EEVEE_FramebufferList *fbl = ((EEVEE_Data *)vedata)->fbl;
+	EEVEE_EffectsInfo *effects = stl->effects;
 	EEVEE_ViewLayerData *sldata = EEVEE_view_layer_data_ensure();
 
 	/* Default framebuffer and texture */
@@ -185,6 +197,9 @@ static void eevee_draw_background(void *vedata)
 	               (stl->effects->enabled_effects & (EFFECT_VOLUMETRIC | EFFECT_SSR)) != 0) ? 4 : 1;
 
 	while (loop_ct--) {
+		float clear_col[4] = {0.0f, 0.0f, 0.0f, 0.0f};
+		float clear_depth = 1.0f;
+		unsigned int clear_stencil = 0xFF;
 		unsigned int primes[3] = {2, 3, 7};
 		double offset[3] = {0.0, 0.0, 0.0};
 		double r[3];
@@ -228,18 +243,11 @@ static void eevee_draw_background(void *vedata)
 		EEVEE_draw_shadows(sldata, psl);
 		DRW_stats_group_end();
 
-		/* Attach depth to the hdr buffer and bind it */
-		DRW_framebuffer_texture_detach(dtxl->depth);
-		DRW_framebuffer_texture_attach(fbl->main, dtxl->depth, 0, 0);
-		DRW_framebuffer_bind(fbl->main);
-		if (DRW_state_draw_background()) {
-			DRW_framebuffer_clear(false, true, true, NULL, 1.0f);
-		}
-		else {
-			/* We need to clear the alpha chanel in this case. */
-			float clear_col[4] = {0.0f, 0.0f, 0.0f, 0.0f};
-			DRW_framebuffer_clear(true, true, true, clear_col, 1.0f);
-		}
+		GPU_framebuffer_bind(fbl->main_fb);
+		GPUFrameBufferBits clear_bits = GPU_DEPTH_BIT;
+		clear_bits |= (DRW_state_draw_background()) ? 0 : GPU_COLOR_BIT;
+		clear_bits |= ((stl->effects->enabled_effects & EFFECT_SSS) != 0) ? GPU_STENCIL_BIT : 0;
+		GPU_framebuffer_clear(fbl->main_fb, clear_bits, clear_col, clear_depth, clear_stencil);
 
 		/* Depth prepass */
 		DRW_stats_group_start("Prepass");
@@ -295,11 +303,8 @@ static void eevee_draw_background(void *vedata)
 		}
 	}
 
-	/* Restore default framebuffer */
-	DRW_framebuffer_texture_attach(dfbl->default_fb, dtxl->depth, 0, 0);
-	DRW_framebuffer_bind(dfbl->default_fb);
-
-	/* Tonemapping */
+	/* Tonemapping and transfer result to default framebuffer. */
+	GPU_framebuffer_bind(dfbl->default_fb);
 	DRW_transform_to_display(stl->effects->final_tx);
 
 	/* Debug : Ouput buffer to view. */
@@ -308,25 +313,25 @@ static void eevee_draw_background(void *vedata)
 			if (txl->maxzbuffer) DRW_transform_to_display(txl->maxzbuffer);
 			break;
 		case 2:
-			if (stl->g_data->ssr_pdf_output) DRW_transform_to_display(stl->g_data->ssr_pdf_output);
+			if (effects->ssr_pdf_output) DRW_transform_to_display(effects->ssr_pdf_output);
 			break;
 		case 3:
-			if (txl->ssr_normal_input) DRW_transform_to_display(txl->ssr_normal_input);
+			if (effects->ssr_normal_input) DRW_transform_to_display(effects->ssr_normal_input);
 			break;
 		case 4:
-			if (txl->ssr_specrough_input) DRW_transform_to_display(txl->ssr_specrough_input);
+			if (effects->ssr_specrough_input) DRW_transform_to_display(effects->ssr_specrough_input);
 			break;
 		case 5:
 			if (txl->color_double_buffer) DRW_transform_to_display(txl->color_double_buffer);
 			break;
 		case 6:
-			if (stl->g_data->gtao_horizons_debug) DRW_transform_to_display(stl->g_data->gtao_horizons_debug);
+			if (effects->gtao_horizons_debug) DRW_transform_to_display(effects->gtao_horizons_debug);
 			break;
 		case 7:
-			if (txl->gtao_horizons) DRW_transform_to_display(txl->gtao_horizons);
+			if (effects->gtao_horizons) DRW_transform_to_display(effects->gtao_horizons);
 			break;
 		case 8:
-			if (txl->sss_data) DRW_transform_to_display(txl->sss_data);
+			if (effects->sss_data) DRW_transform_to_display(effects->sss_data);
 			break;
 		default:
 			break;