Eevee: Start Implementation of Cascaded Shadow Maps

1 files changed, 117 insertions, 21 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_lights.c b/source/blender/draw/engines/eevee/eevee_lights.c
index 6c694b05e6a..7c4a5523ecd 100644
--- a/source/blender/draw/engines/eevee/eevee_lights.c
+++ b/source/blender/draw/engines/eevee/eevee_lights.c
@@ -90,11 +90,11 @@ void EEVEE_lights_cache_add(EEVEE_StorageList *stl, Object *ob)
 		DRW_lamp_engine_data_free((void *)led);
 
 		if (la->mode & (LA_SHAD_BUF | LA_SHAD_RAY)) {
-			if (la->type == LA_SUN && linfo->num_map < MAX_SHADOW_MAP) {
-				led->sto = MEM_mallocN(sizeof(EEVEE_ShadowMapData), "EEVEE_ShadowMapData");
-				((EEVEE_ShadowMapData *)led->sto)->shadow_id = linfo->num_map;
-				linfo->shadow_map_ref[linfo->num_map] = ob;
-				linfo->num_map++;
+			if (la->type == LA_SUN && linfo->num_cascade < MAX_SHADOW_CASCADE) {
+				led->sto = MEM_mallocN(sizeof(EEVEE_ShadowCascadeData), "EEVEE_ShadowCascadeData");
+				((EEVEE_ShadowCascadeData *)led->sto)->shadow_id = linfo->num_cascade;
+				linfo->shadow_cascade_ref[linfo->num_cascade] = ob;
+				linfo->num_cascade++;
 			}
 			else if ((la->type == LA_SPOT || la->type == LA_LOCAL || la->type == LA_AREA)
 			          && linfo->num_cube < MAX_SHADOW_CUBE) {
@@ -150,7 +150,7 @@ void EEVEE_lights_cache_finish(EEVEE_StorageList *stl, EEVEE_TextureList *txl, E
 			DRW_framebuffer_texture_attach(fbl->shadow_map_fb, txl->shadow_depth_map_pool, 0, 0);
 	}
 	if (!txl->shadow_depth_cascade_pool) {
-		txl->shadow_depth_cascade_pool = DRW_texture_create_2D_array(512, 512, MAX2(1, linfo->num_cascade), DRW_TEX_DEPTH_24, DRW_TEX_FILTER | DRW_TEX_COMPARE, NULL);
+		txl->shadow_depth_cascade_pool = DRW_texture_create_2D_array(512, 512, MAX2(1, linfo->num_cascade * MAX_CASCADE_NUM), DRW_TEX_DEPTH_24, DRW_TEX_FILTER | DRW_TEX_COMPARE, NULL);
 		if (fbl->shadow_cascade_fb)
 			DRW_framebuffer_texture_attach(fbl->shadow_cascade_fb, txl->shadow_depth_map_pool, 0, 0);
 	}
@@ -293,6 +293,83 @@ static void eevee_shadow_map_setup(Object *ob, EEVEE_LampsInfo *linfo, EEVEE_Lam
 	evli->shadowid = (float)(MAX_SHADOW_CUBE + evsmp->shadow_id);
 }
 
+#define LERP(t, a, b) ((a) + (t) * ((b) - (a)))
+
+static void eevee_shadow_cascade_setup(Object *ob, EEVEE_LampsInfo *linfo, EEVEE_LampEngineData *led)
+{
+	/* Camera Matrices */
+	float persmat[4][4], persinv[4][4];
+	/* Lamps Matrices */
+	float viewmat[4][4], projmat[4][4];
+	float minvec[3], maxvec[3];
+	int cascade_ct = MAX_CASCADE_NUM;
+
+	EEVEE_ShadowCascadeData *evscp = (EEVEE_ShadowCascadeData *)led->sto;
+	EEVEE_Light *evli = linfo->light_data + evscp->light_id;
+	EEVEE_ShadowCascade *evsh = linfo->shadow_cascade_data + evscp->shadow_id;
+	Lamp *la = (Lamp *)ob->data;
+
+	/* The technique consists into splitting
+	 * the view frustum into several sub-frustum
+	 * that are individually receiving one shadow map */
+
+	/* For each cascade */
+	for (int c = 0; c < cascade_ct; ++c) {
+		float splitnear = LERP(((float)(c) / cascade_ct), -1.0f, 1.0f);
+		float splitfar = LERP(((float)(c + 1) / cascade_ct), -1.0f, 1.0f);
+
+		/* Given 8 frustrum corners */
+		float corners[8][4] = {
+			/* Far Cap */
+			{-1.0f, -1.0f, splitfar, 1.0f},
+			{ 1.0f, -1.0f, splitfar, 1.0f},
+			{-1.0f,  1.0f, splitfar, 1.0f},
+			{ 1.0f,  1.0f, splitfar, 1.0f},
+			/* Near Cap */
+			{-1.0f, -1.0f, splitnear, 1.0f},
+			{ 1.0f, -1.0f, splitnear, 1.0f},
+			{-1.0f,  1.0f, splitnear, 1.0f},
+			{ 1.0f,  1.0f, splitnear, 1.0f}
+		};
+
+		/* Transform them into world space */
+		DRW_viewport_matrix_get(persmat, DRW_MAT_PERS);
+		invert_m4_m4(persinv, persmat);
+		for (int i = 0; i < 8; ++i)	{
+			mul_m4_v4(persinv, corners[i]);
+			mul_v3_fl(corners[i], 1.0f / corners[i][3]);
+			corners[i][3] = 1.0f;
+		}
+
+		/* Project them into light space */
+		invert_m4_m4(viewmat, ob->obmat);
+		normalize_v3(viewmat[0]);
+		normalize_v3(viewmat[1]);
+		normalize_v3(viewmat[2]);
+
+		for (int i = 0; i < 8; ++i)	{
+			mul_m4_v4(viewmat, corners[i]);
+		}
+
+		/* compute the minimum bounding box */
+		INIT_MINMAX(minvec, maxvec);
+		for (int i = 0; i < 8; ++i)	{
+			minmax_v3v3_v3(minvec, maxvec, corners[i]);
+		}
+
+		/* expand the bounding box to cover light range */
+		orthographic_m4(projmat, minvec[0], maxvec[0], minvec[1], maxvec[1], la->clipsta, la->clipend);
+
+		mul_m4_m4m4(evscp->viewprojmat[c], projmat, viewmat);
+		mul_m4_m4m4(evsh->shadowmat[c], texcomat, evscp->viewprojmat[c]);
+	}
+
+	evsh->bias = 0.005f * la->bias;
+	evsh->count = (float)cascade_ct;
+
+	evli->shadowid = (float)(MAX_SHADOW_CUBE + MAX_SHADOW_MAP + evscp->shadow_id);
+}
+
 void EEVEE_lights_update(EEVEE_StorageList *stl)
 {
 	EEVEE_LampsInfo *linfo = stl->lamps;
@@ -314,10 +391,10 @@ void EEVEE_lights_update(EEVEE_StorageList *stl)
 		eevee_shadow_map_setup(ob, linfo, led);
 	}
 
-	// for (i = 0; (ob = linfo->shadow_cascade_ref[i]) && (i < MAX_SHADOW_CASCADE); i++) {
-	// 	EEVEE_LampEngineData *led = (EEVEE_LampEngineData *)DRW_lamp_engine_data_get(ob, &viewport_eevee_type);
-	// 	eevee_shadow_map_setup(ob, linfo, led);
-	// }
+	for (i = 0; (ob = linfo->shadow_cascade_ref[i]) && (i < MAX_SHADOW_CASCADE); i++) {
+		EEVEE_LampEngineData *led = (EEVEE_LampEngineData *)DRW_lamp_engine_data_get(ob, &viewport_eevee_type);
+		eevee_shadow_cascade_setup(ob, linfo, led);
+	}
 
 	DRW_uniformbuffer_update(stl->light_ubo, &linfo->light_data);
 	DRW_uniformbuffer_update(stl->shadow_ubo, &linfo->shadow_cube_data); /* Update all data at once */
@@ -355,19 +432,38 @@ void EEVEE_draw_shadows(EEVEE_Data *vedata)
 		DRW_draw_pass(psl->shadow_cube_pass);
 	}
 
+#if 0
 	/* Standard Shadow Maps */
-	// DRW_framebuffer_bind(fbl->shadow_map_fb);
-	// DRW_framebuffer_clear(false, true, false, NULL, 1.0);
+	DRW_framebuffer_bind(fbl->shadow_map_fb);
+	DRW_framebuffer_clear(false, true, false, NULL, 1.0);
+
+	/* Render each shadow to one layer of the array */
+	for (i = 0; (ob = linfo->shadow_map_ref[i]) && (i < MAX_SHADOW_MAP); i++) {
+		EEVEE_LampEngineData *led = (EEVEE_LampEngineData *)DRW_lamp_engine_data_get(ob, &viewport_eevee_type);
+		EEVEE_ShadowMapData *evsmd = (EEVEE_ShadowMapData *)led->sto;
 
-	// /* Render each shadow to one layer of the array */
-	// for (i = 0; (ob = linfo->shadow_map_ref[i]) && (i < MAX_SHADOW_MAP); i++) {
-	// 	EEVEE_LampEngineData *led = (EEVEE_LampEngineData *)DRW_lamp_engine_data_get(ob, &viewport_eevee_type);
-	// 	EEVEE_ShadowMapData *evsmd = (EEVEE_ShadowMapData *)led->sto;
+		linfo->layer = i;
+		copy_m4_m4(linfo->shadowmat, evsmd->viewprojmat);
+		DRW_draw_pass(vedata->psl->shadow_pass);
+	}
+#endif
 
-	// 	linfo->layer = i;
-	// 	copy_m4_m4(linfo->shadowmat, evsmd->viewprojmat);
-	// 	DRW_draw_pass(vedata->psl->shadow_pass);
-	// }
+	/* Cascaded Shadow Maps */
+	DRW_framebuffer_bind(fbl->shadow_cascade_fb);
+	DRW_framebuffer_clear(false, true, false, NULL, 1.0);
 
-	// DRW_framebuffer_bind(e_data.shadow_cascade_fb);
+	/* Render each shadow to one layer of the array */
+	for (i = 0; (ob = linfo->shadow_cascade_ref[i]) && (i < MAX_SHADOW_CASCADE); i++) {
+		EEVEE_LampEngineData *led = (EEVEE_LampEngineData *)DRW_lamp_engine_data_get(ob, &viewport_eevee_type);
+		EEVEE_ShadowCascadeData *evscd = (EEVEE_ShadowCascadeData *)led->sto;
+		EEVEE_ShadowRender *srd = &linfo->shadow_render_data;
+
+		srd->layer = i;
+		for (int j = 0; j < MAX_CASCADE_NUM; ++j) {
+			copy_m4_m4(srd->shadowmat[j], evscd->viewprojmat[j]);
+		}
+		DRW_uniformbuffer_update(stl->shadow_render_ubo, &linfo->shadow_render_data);
+
+		DRW_draw_pass(psl->shadow_cascade_pass);
+	}
 }